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Sample records for adjacent nozzle segments

  1. Apparatus and methods for impingement cooling of an undercut region adjacent a side wall of a turbine nozzle segment

    DOEpatents

    Burdgick, Steven Sebastian; Itzel, Gary Michael

    2001-01-01

    A gas turbine nozzle segment has outer and inner bands. Each band includes a side wall, a cover and an impingement plate between the cover and nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through apertures of the impingement plate to cool the nozzle wall. The side wall of the band and inturned flange define with the nozzle wall an undercut region. The inturned flange has a plurality of apertures for directing cooling steam to cool the side wall between adjacent nozzle segments.

  2. Apparatus for impingement cooling a side wall adjacent an undercut region of a turbine nozzle segment

    DOEpatents

    Burdgick, Steven Sebastian

    2002-01-01

    A gas turbine nozzle segment has outer and inner bands and vanes therebetween. Each band includes a side wall, a cover and an impingement plate between the cover and nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through apertures of the impingement plate to cool the nozzle wall. The side wall of the band and inturned flange define with the nozzle wall an undercut region. Slots are formed through the inturned flange along the nozzle side wall. A plate having through-apertures extending between opposite edges thereof is disposed in each slot, the slots and plates being angled such that the cooling medium exiting the apertures in the second cavity lie close to the side wall for focusing and targeting cooling medium onto the side wall.

  3. Adjacent segment disease.

    PubMed

    Virk, Sohrab S; Niedermeier, Steven; Yu, Elizabeth; Khan, Safdar N

    2014-08-01

    EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Understand the forces that predispose adjacent cervical segments to degeneration. 2. Understand the challenges of radiographic evaluation in the diagnosis of cervical and lumbar adjacent segment disease. 3. Describe the changes in biomechanical forces applied to adjacent segments of lumbar vertebrae with fusion. 4. Know the risk factors for adjacent segment disease in spinal fusion. Adjacent segment disease (ASD) is a broad term encompassing many complications of spinal fusion, including listhesis, instability, herniated nucleus pulposus, stenosis, hypertrophic facet arthritis, scoliosis, and vertebral compression fracture. The area of the cervical spine where most fusions occur (C3-C7) is adjacent to a highly mobile upper cervical region, and this contributes to the biomechanical stress put on the adjacent cervical segments postfusion. Studies have shown that after fusion surgery, there is increased load on adjacent segments. Definitive treatment of ASD is a topic of continuing research, but in general, treatment choices are dictated by patient age and degree of debilitation. Investigators have also studied the risk factors associated with spinal fusion that may predispose certain patients to ASD postfusion, and these data are invaluable for properly counseling patients considering spinal fusion surgery. Biomechanical studies have confirmed the added stress on adjacent segments in the cervical and lumbar spine. The diagnosis of cervical ASD is complicated given the imprecise correlation of radiographic and clinical findings. Although radiological and clinical diagnoses do not always correlate, radiographs and clinical examination dictate how a patient with prolonged pain is treated. Options for both cervical and lumbar spine ASD include fusion and/or decompression. Current studies are encouraging regarding the adoption of arthroplasty in spinal surgery, but more long

  4. Adjacent Segment Pathology after Lumbar Spinal Fusion.

    PubMed

    Lee, Jae Chul; Choi, Sung-Woo

    2015-10-01

    One of the major clinical issues encountered after lumbar spinal fusion is the development of adjacent segment pathology (ASP) caused by increased mechanical stress at adjacent segments, and resulting in various radiographic changes and clinical symptoms. This condition may require surgical intervention. The incidence of ASP varies with both the definition and methodology adopted in individual studies; various risk factors for this condition have been identified, although a significant controversy still exists regarding their significance. Motion-preserving devices have been developed, and some studies have shown their efficacy of preventing ASP. Surgeons should be aware of the risk factors of ASP when planning a surgery, and accordingly counsel their patients preoperatively. PMID:26435804

  5. Segmented inlet nozzle for gas turbine, and methods of installation

    DOEpatents

    Klompas, Nicholas

    1985-01-01

    A gas turbine nozzle guide vane assembly is formed of individual arcuate nozzle segments. The arcuate nozzle segments are elastically joined to each other to form a complete ring, with edges abutted to prevent leakage. The resultant nozzle ring is included within the overall gas turbine stationary structure and secured by a mounting arrangement which permits relative radial movement at both the inner and outer mountings. A spline-type outer mounting provides circumferential retention. A complete rigid nozzle ring with freedom to "float" radially results. Specific structures are disclosed for the inner and outer mounting arrangements. A specific tie-rod structure is also disclosed for elastically joining the individual nozzle segments. Also disclosed is a method of assembling the nozzle ring subassembly-by-subassembly into a gas turbine employing temporary jacks.

  6. Support pedestals for interconnecting a cover and nozzle band wall in a gas turbine nozzle segment

    DOEpatents

    Yu, Yufeng Phillip; Itzel, Gary Michael; Webbon, Waylon Willard; Bagepalli, Radhakrishna; Burdgick, Steven Sebastian; Kellock, Iain Robertson

    2002-01-01

    A gas turbine nozzle segment has outer and inner band portions. Each band portion includes a nozzle wall, a cover and an impingement plate between the cover and nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through the apertures of the impingement plate to cool the nozzle wall. Structural pedestals interconnect the cover and nozzle wall and pass through holes in the impingement plate to reduce localized stress otherwise resulting from a difference in pressure within the chamber of the nozzle segment and the hot gas path and the fixed turbine casing surrounding the nozzle stage. The pedestals may be cast or welded to the cover and nozzle wall.

  7. Method of joining a vane cavity insert to a nozzle segment of a gas turbine

    DOEpatents

    Burdgick, Steven Sebastian

    2002-01-01

    An insert containing apertures for impingement cooling a nozzle vane of a nozzle segment in a gas turbine is inserted into one end of the vane. The leading end of the insert is positioned slightly past a rib adjacent the opposite end of the vane through which the insert is inserted. The end of the insert is formed or swaged into conformance with the inner margin of the rib. The insert is then brazed or welded to the rib.

  8. Adjacent Segment Pathology after Anterior Cervical Fusion

    PubMed Central

    Chung, Jae Yoon; Park, Jong-Beom; Seo, Hyoung-Yeon

    2016-01-01

    Anterior cervical fusion has become a standard of care for numerous pathologic conditions of the cervical spine. However, subsequent development of clinically significant disc disease at levels adjacent to fused discs is a serious long-term complication of this procedure. As more patients live longer after surgery, it is foreseeable that adjacent segment pathology (ASP) will develop in increasing numbers of patients. Also, ASP has been studied more intensively with the recent popularity of motion preservation technologies like total disc arthroplasty. The true nature and scope of ASP remains poorly understood. The etiology of ASP is most likely multifactorial. Various factors including altered biomechanical stresses, surgical disruption of soft tissue and the natural history of cervical disc disease contribute to the development of ASP. General factors associated with disc degeneration including gender, age, smoking and sports may play a role in the development of ASP. Postoperative sagittal alignment and type of surgery are also considered potential causes of ASP. Therefore, a spine surgeon must be particularly careful to avoid unnecessary disruption of the musculoligamentous structures, reduced risk of direct injury to the disc during dissection and maintain a safe margin between the plate edge and adjacent vertebrae during anterior cervical fusion. PMID:27340541

  9. Adjacent Segment Pathology after Anterior Cervical Fusion.

    PubMed

    Chung, Jae Yoon; Park, Jong-Beom; Seo, Hyoung-Yeon; Kim, Sung Kyu

    2016-06-01

    Anterior cervical fusion has become a standard of care for numerous pathologic conditions of the cervical spine. However, subsequent development of clinically significant disc disease at levels adjacent to fused discs is a serious long-term complication of this procedure. As more patients live longer after surgery, it is foreseeable that adjacent segment pathology (ASP) will develop in increasing numbers of patients. Also, ASP has been studied more intensively with the recent popularity of motion preservation technologies like total disc arthroplasty. The true nature and scope of ASP remains poorly understood. The etiology of ASP is most likely multifactorial. Various factors including altered biomechanical stresses, surgical disruption of soft tissue and the natural history of cervical disc disease contribute to the development of ASP. General factors associated with disc degeneration including gender, age, smoking and sports may play a role in the development of ASP. Postoperative sagittal alignment and type of surgery are also considered potential causes of ASP. Therefore, a spine surgeon must be particularly careful to avoid unnecessary disruption of the musculoligamentous structures, reduced risk of direct injury to the disc during dissection and maintain a safe margin between the plate edge and adjacent vertebrae during anterior cervical fusion. PMID:27340541

  10. Side wall cooling for nozzle segments for a gas turbine

    DOEpatents

    Burdgick, Steven Sebastian

    2002-01-01

    A nozzle vane segment includes outer and inner band portions with a vane extending therebetween and defining first and second cavities separated by an impingement plate for flowing cooling medium for impingement cooling of nozzle side walls. The side wall of each nozzle segment has an undercut region. The impingement plate has an inturned flange with a plurality of openings. Cooling inserts or receptacles having an open end are received in the openings and the base and side walls of the receptacles have apertures for receiving cooling medium from the first cavity and directing the cooling medium for impingement cooling of the side wall of the nozzle segment and a portion of the nozzle wall.

  11. Adjacent Segment Disease Perspective and Review of the Literature

    PubMed Central

    Saavedra-Pozo, Fanor M.; Deusdara, Renato A. M.; Benzel, Edward C.

    2014-01-01

    Background Adjacent segment disease has become a common topic in spine surgery circles because of the significant increase in fusion surgery in recent years and the development of motion preservation technologies that theoretically should lead to a decrease in this pathology. The purpose of this review is to organize the evidence available in the current literature on this subject. Methods For this literature review, a search was conducted in PubMed with the following keywords: adjacent segment degeneration and disease. Selection, review, and analysis of the literature were completed according to level of evidence. Results The PubMed search identified 850 articles, from which 41 articles were selected and reviewed. The incidence of adjacent segment disease in the cervical spine is close to 3% without a significant statistical difference between surgical techniques (fusion vs arthroplasty). Authors report the incidence of adjacent segment disease in the lumbar spine to range from 2% to 14%. Damage to the posterior ligamentous complex and sagittal imbalances are important risk factors for both degeneration and disease. Conclusion Insufficient evidence exists at this point to support the idea that total disc arthroplasty is superior to fusion procedures in minimizing the incidence of adjacent segment disease. The etiology is most likely multifactorial but it is becoming abundantly clear that adjacent segment disease is not caused by motion segment fusion alone. Fusion plus the presence of abnormal end-fusion alignment appears to be a major factor in creating end-fusion stresses that result in adjacent segment degeneration and subsequent disease. The data presented cast further doubt on previously established rationales for total disc arthroplasty, at least with regard to the effect of total disc arthroplasty on adjacent segment degeneration pathology. PMID:24688337

  12. Vortex nozzle for segmenting and transporting metal chips from turning operations

    DOEpatents

    Bieg, L.F.

    1993-04-20

    Apparatus for collecting, segmenting and conveying metal chips from machining operations utilizes a compressed gas driven vortex nozzle for receiving the chip and twisting it to cause the chip to segment through the application of torsional forces to the chip. The vortex nozzle is open ended and generally tubular in shape with a converging inlet end, a constant diameter throat section and a diverging exhaust end. Compressed gas is discharged through angled vortex ports in the nozzle throat section to create vortex flow in the nozzle and through an annular inlet at the entrance to the converging inlet end to create suction at the nozzle inlet and cause ambient air to enter the nozzle. The vortex flow in the nozzle causes the metal chip to segment and the segments thus formed to pass out of the discharge end of the nozzle where they are collected, cleaned and compacted as needed.

  13. Apparatus and methods for impingement cooling of a side wall of a turbine nozzle segment

    DOEpatents

    Burdgick, Steven Sebastian

    2002-01-01

    A gas turbine nozzle segment has outer and inner bands and a vane therebetween. Each band includes a nozzle wall, a side wall, a cover and an impingement plate between the cover and the nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through apertures of the impingement plate to cool the nozzle wall. The side wall of the band and inturned flange define with the nozzle wall an undercut region. The impingement plate has a turned flange welded to the inturned flange. A backing plate overlies the turned flange and aligned apertures are formed through the backing plate and turned flange to direct and focus cooling flow onto the side wall of the nozzle segment.

  14. Nozzle

    DOEpatents

    Chen, Alexander G.; Cohen, Jeffrey M.

    2009-06-16

    A fuel injector has a number of groups of nozzles. The groups are generally concentric with an injector axis. Each nozzle defines a gas flowpath having an outlet for discharging a fuel/air mixture jet. There are means for introducing the fuel to the air. One or more groups of the nozzles are oriented to direct the associated jets skew to the injector axis.

  15. Method of controlling the side wall thickness of a turbine nozzle segment for improved cooling

    DOEpatents

    Burdgick, Steven Sebastian

    2002-01-01

    A gas turbine nozzle segment has outer and inner bands and a vane extending therebetween. Each band has a side wall, a cover and an impingement plate between the cover and nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through apertures of the impingement plate to cool the nozzle wall. The side wall of the band has an inturned flange defining with the nozzle wall an undercut region. The outer surface of the side wall is provided with a step prior to welding the cover to the side wall. A thermal barrier coating is applied in the step and, after the cover is welded to the side wall, the side wall is finally machined to a controlled thickness removing all, some or none of the coating.

  16. Turbine nozzle/nozzle support structure

    DOEpatents

    Boyd, Gary L.; Shaffer, James E.

    1995-01-01

    An axial flow turbine's nozzle/nozzle support structure having a cantilevered nozzle outer structure including an outer shroud and airfoil vanes extending radially inwardly therefrom, an inner shroud radially adjacent the inner end of the airfoil vanes and cooperatively disposed relative to the outer shroud to provide an annular fluid flow path, an inner and an outer support ring respectively arranged radially inside the inner shroud and axially adjacent a portion of the outer shroud, and pins extending through such portion and into the outer support ring. The inner support ring or inner shroud has a groove therein bounded by end walls for receiving and being axially abuttable with a locating projection from the adjacent airfoil vane, inner shroud, or inner support ring. The nozzle outer structure may comprise segments each of which has a single protrusion which is axially engageable with the outer support ring or, alternatively, a first and second protrusion which are arcuately and axially separated and which include axial openings therein whereby first and second protrusions on respective, arcuately adjacent nozzle segments have axial openings therein which are alignable with connector openings in the outer support ring and within each of such aligned openings a pin is receivable. The inner shroud may, likewise, comprise segments which, when assembled in operating configuration, have a 360 degree expanse.

  17. Turbine nozzle/nozzle support structure

    DOEpatents

    Boyd, Gary L.; Shaffer, James E.

    1996-01-01

    An axial flow turbine's nozzle/nozzle support structure having a cantilevered nozzle outer structure including an outer shroud and airfoil vanes extending radially inwardly therefrom, an inner shroud radially adjacent the inner end of the airfoil vanes and cooperatively disposed relative to the outer shroud to provide an annular fluid flow path, an inner and an outer support ring respectively arranged radially inside the inner shroud and axially adjacent a portion of the outer shroud, and pins extending through such portion and into the outer support ring. The inner support ring or inner shroud has a groove therein bounded by end walls for receiving and being axially abuttable with a locating projection from the adjacent airfoil vane, inner shroud, or inner support ring. The nozzle outer structure may comprise segments each of which has a single protrusion which is axially engageable with the outer support ring or, alternatively, a first and second protrusion which are arcuately and axially separated and which include axial openings therein whereby first and second protrusions on respective, arcuately adjacent nozzle segments have axial openings therein which are alignable with connector openings in the outer support ring and within each of such aligned openings a pin is receivable. The inner shroud may, likewise, comprise segments which, when assembled in operating configuration, have a 360 degree expanse.

  18. Turbine nozzle/nozzle support structure

    DOEpatents

    Boyd, Gary L.; Shaffer, James E.

    1997-01-01

    An axial flow turbine's nozzle/nozzle support structure having a cantilevered nozzle outer structure including an outer shroud and airfoil vanes extending radially inwardly therefrom, an inner shroud radially adjacent the inner end of the airfoil vanes and cooperatively disposed relative to the outer shroud to provide an annular fluid flow path, an inner and an outer support ring respectively arranged radially inside the inner shroud and axially adjacent a portion of the outer shroud, and pins extending through such portion and into the outer support ring. The inner support ring or inner shroud has a groove therein bounded by end walls for receiving and being axially abuttable with a locating projection from the adjacent airfoil vane, inner shroud, or inner support ring. The nozzle outer structure may comprise segments each of which has a single protrusion which is axially engageable with the outer support ring or, alternatively, a first and second protrusion which are arcuately and axially separated and which include axial openings therein whereby first and second protrusions on respective, arcuately adjacent nozzle segments have axial openings therein which are alignable with connector openings in the outer support ring and within each of such aligned openings a pin is receivable. The inner shroud may, likewise, comprise segments which, when assembled in operating configuration, have a 360 degree expanse.

  19. Turbine nozzle/nozzle support structure

    DOEpatents

    Boyd, G.L.; Shaffer, J.E.

    1997-01-07

    An axial flow turbine`s nozzle/nozzle support structure is described having a cantilevered nozzle outer structure including an outer shroud and airfoil vanes extending radially inwardly therefrom, an inner shroud radially adjacent the inner end of the airfoil vanes and cooperatively disposed relative to the outer shroud to provide an annular fluid flow path, an inner and an outer support ring respectively arranged radially inside the inner shroud and axially adjacent a portion of the outer shroud, and pins extending through such portion and into the outer support ring. The inner support ring or inner shroud has a groove therein bounded by end walls for receiving and being axially abuttable with a locating projection from the adjacent airfoil vane, inner shroud, or inner support ring. The nozzle outer structure may comprise segments each of which has a single protrusion which is axially engageable with the outer support ring or, alternatively, a first and second protrusion which are arcuately and axially separated and which include axial openings therein whereby first and second protrusions on respective, arcuately adjacent nozzle segments have axial openings therein which are alignable with connector openings in the outer support ring and within each of such aligned openings a pin is receivable. The inner shroud may, likewise, comprise segments which, when assembled in operating configuration, have a 360 degree expanse. 6 figs.

  20. Turbine nozzle/nozzle support structure

    DOEpatents

    Boyd, G.L.; Shaffer, J.E.

    1995-08-15

    An axial flow turbine`s nozzle/nozzle support structure is described having a cantilevered nozzle outer structure including an outer shroud and airfoil vanes extending radially inwardly therefrom, an inner shroud radially adjacent the inner end of the airfoil vanes and cooperatively disposed relative to the outer shroud to provide an annular fluid flow path, an inner and an outer support ring respectively arranged radially inside the inner shroud and axially adjacent a portion of the outer shroud, and pins extending through such portion and into the outer support ring. The inner support ring or inner shroud has a groove therein bounded by end walls for receiving and being axially abuttable with a locating projection from the adjacent airfoil vane, inner shroud, or inner support ring. The nozzle outer structure may comprise segments each of which has a single protrusion which is axially engageable with the outer support ring or, alternatively, a first and second protrusion which are arcuately and axially separated and which include axial openings therein whereby first and second protrusions on respective, arcuately adjacent nozzle segments have axial openings therein which are alignable with connector openings in the outer support ring and within each of such aligned openings a pin is receivable. The inner shroud may, likewise, comprise segments which, when assembled in operating configuration, have a 360 degree expanse. 6 figs.

  1. Turbine nozzle/nozzle support structure

    DOEpatents

    Boyd, G.L.; Shaffer, J.E.

    1996-09-10

    An axial flow turbine`s nozzle/nozzle support structure is described having a cantilevered nozzle outer structure including an outer shroud and airfoil vanes extending radially inwardly therefrom, an inner shroud radially adjacent the inner end of the airfoil vanes and cooperatively disposed relative to the outer shroud to provide an annular fluid flow path, an inner and an outer support ring respectively arranged radially inside the inner shroud and axially adjacent a portion of the outer shroud, and pins extending through such portion and into the outer support ring. The inner support ring or inner shroud has a groove therein bounded by end walls for receiving and being axially abuttable with a locating projection from the adjacent airfoil vane, inner shroud, or inner support ring. The nozzle outer structure may comprise segments each of which has a single protrusion which is axially engageable with the outer support ring or, alternatively, a first and second protrusion which are arcuately and axially separated and which include axial openings therein whereby first and second protrusions on respective, arcuately adjacent nozzle segments have axial openings therein which are alignable with connector openings in the outer support ring and within each of such aligned openings a pin is receivable. The inner shroud may, likewise, comprise segments which, when assembled in operating configuration, have a 360 degree expanse. 6 figs.

  2. Groups of adjacent contour segments for object detection.

    PubMed

    Ferrari, V; Fevrier, L; Jurie, F; Schmid, C

    2008-01-01

    We present a family of scale-invariant local shape features formed by chains of k connected, roughly straight contour segments (kAS), and their use for object class detection. kAS are able to cleanly encode pure fragments of an object boundary, without including nearby clutter. Moreover, they offer an attractive compromise between information content and repeatability, and encompass a wide variety of local shape structures. We also define a translation and scale invariant descriptor encoding the geometric configuration of the segments within a kAS, making kAS easy to reuse in other frameworks, for example as a replacement or addition to interest points. Software for detecting and describing kAS is released on lear.inrialpes.fr/software. We demonstrate the high performance of kAS within a simple but powerful sliding-window object detection scheme. Through extensive evaluations, involving eight diverse object classes and more than 1400 images, we 1) study the evolution of performance as the degree of feature complexity k varies and determine the best degree; 2) show that kAS substantially outperform interest points for detecting shape-based classes; 3) compare our object detector to the recent, state-of-the-art system by Dalal and Triggs [4]. PMID:18000323

  3. Sacroiliac Joint Fusion Minimally Affects Adjacent Lumbar Segment Motion: A Finite Element Study

    PubMed Central

    Kiapour, Ali; Yerby, Scott A.; Goel, Vijay K.

    2015-01-01

    Background Adjacent segment disease is a recognized consequence of fusion in the spinal column. Fusion of the sacroiliac joint is an effective method of pain reduction. Although effective, the consequences of sacroiliac joint fusion and the potential for adjacent segment disease for the adjacent lumbar spinal levels is unknown. The objective of this study was to quantify the change in range of motion of the sacroiliac joint and the adjacent lumbar spinal motion segments due to sacroiliac joint fusion and compare these changes to previous literature to assess the potential for adjacent segment disease in the lumbar spine. Methods An experimentally validated finite element model of the lumbar spine and pelvis was used to simulate a fusion of the sacroiliac joint using three laterally placed triangular implants (iFuse Implant System, SI-BONE, Inc., San Jose, CA). The range of motion of the sacroiliac joint and the adjacent lumbar spinal motion segments were calculated using a hybrid loading protocol and compared with the intact range of motion in flexion, extension, lateral bending, and axial rotation. Results The range of motions of the treated sacroiliac joints were reduced in flexion, extension, lateral bending, and axial rotation, by 56.6%, 59.5%, 27.8%, and 53.3%, respectively when compared with the intact condition. The stiffening of the sacroiliac joint resulted in increases at the adjacent lumbar motion segment (L5-S1) for flexion, extension, lateral bending, and axial rotation, of 3.0%, 3.7%, 1.1%, and 4.6%, respectively. Conclusions Fusion of the sacroiliac joint resulted in substantial (> 50%) reductions in flexion, extension, and axial rotation of the sacroiliac joint with minimal (< 5%) increases in range of motion in the lumbar spine. Although the predicted increases in lumbar range of motion are minimal after sacroiliac joint fusion, the long-term clinical results remain to be investigated. PMID:26767156

  4. Spondylosis deformans and diffuse idiopathic skeletal hyperostosis (dish) resulting in adjacent segment disease.

    PubMed

    Ortega, Maria; Gonçalves, Rita; Haley, Allison; Wessmann, Annette; Penderis, Jacques

    2012-01-01

    Spondylosis deformans and diffuse idiopathic skeletal hyperostosis (DISH) are usually incidental findings and in most dogs are either asymptomatic or associated with mild clinical signs. Severe spondylosis deformans and DISH can result in complete bony fusion of consecutive vertebral segments. One of the recognised complications following vertebral fusion in human patients is the development of adjacent segment disease, which is defined as degenerative changes, most commonly degenerative intervertebral disc disease, in the mobile vertebral segment neighboring a region of complete vertebral fusion. A similar syndrome following cervical fusion in dogs has been termed the domino effect. The purpose of this retrospective study was to investigate the hypothesis that vertebral fusion occurring secondary to spondylosis deformans or DISH in dogs would protect fused intervertebral disc spaces from undergoing degeneration, but result in adjacent segment disease at neighbouring unfused intervertebral disc spaces. Eight dogs with clinical signs of thoracolumbar myelopathy, magnetic resonance imaging of the thoracolumbar vertebral column, and spondylosis deformans or DISH producing fusion of > or = 2 consecutive intervertebral disc spaces were evaluated. Vertebral fusion of > or = 2 consecutive intervertebral disc spaces was correlated (P = 0.0017) with adjacent segment disease at the neighbouring unfused intervertebral disc space. Vertebral fusion appeared to protect fused intervertebral disc spaces from undergoing degeneration (P < 0.0001). Adjacent segment disease should be considered in dogs with severe spondylosis deformans or DISH occurring in conjunction with a thoracolumbar myelopathy. PMID:22734148

  5. Flight velocity influence on jet noise of conical ejector, annular plug and segmented suppressor nozzles

    NASA Technical Reports Server (NTRS)

    Brausch, J. F.

    1972-01-01

    An F106 aircraft with a J85-13 engine was used for static and flight acoustic and aerodynamic tests of a conical ejector, an unsuppressed annular plug, and three segmented suppressor nozzles. Static 100 ft. arc data, corrected for influences other than jet noise, were extrapolated to a 300 ft. sideline for comparison to 300 ft. altitude flyover data at M = 0.4. Data at engine speeds of 80 to 100% (max dry) static and 88 to 100% flight are presented. Flight velocity influence on noise is shown on peak OASPL and PNL, PNL directivity, EPNL and chosen spectra. Peak OASPL and PNL plus EPNL suppression levels are included showing slightly lower flight than static peak PNL suppression but greater EPNL than peak PNL suppression. Aerodynamic performance was as anticipated and closely matched model work for the 32-spoke nozzle.

  6. Load Rate of Facet Joints at the Adjacent Segment Increased After Fusion

    PubMed Central

    Li, Hui; Pei, Bao-Qing; Yang, Jin-Cai; Hai, Yong; Li, De-Yu; Wu, Shu-Qin

    2015-01-01

    Background: The cause of the adjacent segment degeneration (ASD) after fusion remains unknown. It is reported that adjacent facet joint stresses increase after anterior cervical discectomy and fusion. This increase of stress rate may lead to tissue injury. Thus far, the load rate of the adjacent segment facet joint after fusion remains unclear. Methods: Six C2–C7 cadaveric spine specimens were loaded under four motion modes: Flexion, extension, rotation, and lateral bending, with a pure moment using a 6° robot arm combined with an optical motion analysis system. The Tecscan pressure test system was used for testing facet joint pressure. Results: The contact mode of the facet joints and distributions of the force center during different motions were recorded. The adjacent segment facet joint forces increased faster after fusion, compared with intact conditions. While the magnitude of pressures increased, there was no difference in distribution modes before and after fusion. No pressures were detected during flexion. The average growth velocity during extension was the fastest and was significantly faster than lateral bending. Conclusions: One of the reasons for cartilage injury was the increasing stress rate of loading. This implies that ASD after fusion may be related to habitual movement before and after fusion. More and faster extension is disadvantageous for the facet joints and should be reduced as much as possible. PMID:25881597

  7. Best Merge Region Growing Segmentation with Integrated Non-Adjacent Region Object Aggregation

    NASA Technical Reports Server (NTRS)

    Tilton, James C.; Tarabalka, Yuliya; Montesano, Paul M.; Gofman, Emanuel

    2012-01-01

    Best merge region growing normally produces segmentations with closed connected region objects. Recognizing that spectrally similar objects often appear in spatially separate locations, we present an approach for tightly integrating best merge region growing with non-adjacent region object aggregation, which we call Hierarchical Segmentation or HSeg. However, the original implementation of non-adjacent region object aggregation in HSeg required excessive computing time even for moderately sized images because of the required intercomparison of each region with all other regions. This problem was previously addressed by a recursive approximation of HSeg, called RHSeg. In this paper we introduce a refined implementation of non-adjacent region object aggregation in HSeg that reduces the computational requirements of HSeg without resorting to the recursive approximation. In this refinement, HSeg s region inter-comparisons among non-adjacent regions are limited to regions of a dynamically determined minimum size. We show that this refined version of HSeg can process moderately sized images in about the same amount of time as RHSeg incorporating the original HSeg. Nonetheless, RHSeg is still required for processing very large images due to its lower computer memory requirements and amenability to parallel processing. We then note a limitation of RHSeg with the original HSeg for high spatial resolution images, and show how incorporating the refined HSeg into RHSeg overcomes this limitation. The quality of the image segmentations produced by the refined HSeg is then compared with other available best merge segmentation approaches. Finally, we comment on the unique nature of the hierarchical segmentations produced by HSeg.

  8. Stepped nozzle

    DOEpatents

    Sutton, G.P.

    1998-07-14

    An insert is described which allows a supersonic nozzle of a rocket propulsion system to operate at two or more different nozzle area ratios. This provides an improved vehicle flight performance or increased payload. The insert has significant advantages over existing devices for increasing nozzle area ratios. The insert is temporarily fastened by a simple retaining mechanism to the aft end of the diverging segment of the nozzle and provides for a multi-step variation of nozzle area ratio. When mounted in place, the insert provides the nozzle with a low nozzle area ratio. During flight, the retaining mechanism is released and the insert ejected thereby providing a high nozzle area ratio in the diverging nozzle segment. 5 figs.

  9. Stepped nozzle

    DOEpatents

    Sutton, George P.

    1998-01-01

    An insert which allows a supersonic nozzle of a rocket propulsion system to operate at two or more different nozzle area ratios. This provides an improved vehicle flight performance or increased payload. The insert has significant advantages over existing devices for increasing nozzle area ratios. The insert is temporarily fastened by a simple retaining mechanism to the aft end of the diverging segment of the nozzle and provides for a multi-step variation of nozzle area ratio. When mounted in place, the insert provides the nozzle with a low nozzle area ratio. During flight, the retaining mechanism is released and the insert ejected thereby providing a high nozzle area ratio in the diverging nozzle segment.

  10. Simultaneous segmentation and generalisation of non-adjacent dependencies from continuous speech.

    PubMed

    Frost, Rebecca L A; Monaghan, Padraic

    2016-02-01

    Language learning requires mastering multiple tasks, including segmenting speech to identify words, and learning the syntactic role of these words within sentences. A key question in language acquisition research is the extent to which these tasks are sequential or successive, and consequently whether they may be driven by distinct or similar computations. We explored a classic artificial language learning paradigm, where the language structure is defined in terms of non-adjacent dependencies. We show that participants are able to use the same statistical information at the same time to segment continuous speech to both identify words and to generalise over the structure, when the generalisations were over novel speech that the participants had not previously experienced. We suggest that, in the absence of evidence to the contrary, the most economical explanation for the effects is that speech segmentation and grammatical generalisation are dependent on similar statistical processing mechanisms. PMID:26638049

  11. Repeated adjacent segment diseases and fractures in osteoporotic patients: a case report

    PubMed Central

    Chen, Hsin-Yao; Chen, Chiu-Liang; Chen, Wei-Liang

    2016-01-01

    Background Pedicle screw instrumentation for treating spinal disorder is becoming increasingly widespread. Many studies have advocated its use to facilitate rigid fixation for spine; however, adjacent segmental disease is a known complication. Instrumented fusion for osteoporotic spines remains a significant challenge for spine surgeons. Prophylactic vertebroplasty for adjacent vertebra has been reported to reduce the complications of junctional compression fractures but has raised a new problem of vertebral subluxation. This case report is a rare and an extreme example with many surgical complications caused by repeated instrumented fusion for osteoporotic spine in a single patient. This patient had various complications including adjacent segmental disease, vertebral subluxation, and junctional fractures on radiographs and magnetic resonance images. Case presentation An 81-year-old Taiwanese woman underwent decompression and instrumented fusion of L4-L5 in Taiwan 10 years ago. Due to degenerative spinal stenosis of L3-L4 and L2-L3, she had decompression with instrumented fusion from L5 to L1 at the previous hospital. However, catastrophic vertebral subluxations with severe neurologic compromise occurred, and she underwent salvage surgeries twice with prolonged instrumented fusion from L5 to T2. The surgeries did not resolve her problems of spinal instability and neurologic complications. Eventually, the patient remained with a Frankel Grade C spinal cord injury. Conclusion Adjacent segmental disease, junctional fracture, and vertebral subluxation are familiar complications following instrumented spinal fusion surgeries for osteoporotic spines. Neurologic injuries following long instrumentation are often serious and difficult to address with surgery alone. Conservative treatments should always be contemplated as an alternative method for patients with poor bone stock. PMID:27555778

  12. Adjacent segment disc pressures following two-level cervical disc replacement versus simulated anterior cervical fusion.

    PubMed

    Laxer, Eric B; Darden, Bruce V; Murrey, Daniel B; Milam, R Alden; Rhyne, Alfred L; Claytor, Brian; Nussman, Donna S; Powers, Timothy W; Davies, Matthew A; Bryant, S Chad; Larsen, Scott P; Bhatt, Meghal; Brodziak, John; Polic, Jelena

    2006-01-01

    Anterior cervical fusion (ACF) has been shown to alter the biomechanics of adjacent segments of the cervical spine. The goal of total disc replacement is to address pathology at a given disc with minimal disruption of the operated or adjacent segments. This study compares the pressure within discs adjacent to either a two-level simulated ACDF or a two-level total disc replacement with the ProDisc-C. A special automated motion testing apparatus was constructed. Four fresh cadaveric cervical spine specimens were affixed to the test stand and tested in flexion and extension under specific loads. Intradiscal, miniature strain-gauge-based transducers were placed in the discs above and below the "treated" levels. The specimens were then tested in flexion and extension. Pressure and overall angular displacement were measured. In the most extreme and highest quality specimen the difference at C3/C4 registered 800 kPa and the difference at C6/C7 registered 50 kPa. This same quality specimen treated with the ProDisc reached a flexion angle at much lower moments, 24.3 degrees at 5 N-m, when compared to the the SACF 12.2 degrees at 8.6 N-m. Therefore, the moment needed to achieve 15 degrees of flexion with the SACF treatment was 5.5 N-m and the ProDisc treatment was only 2.9 N-m. This initial data would indicate that adjacent level discs experience substantially lower pressure after two-level disc replacement when compared to two-level SACF. Additional testing to further support these observations is ongoing. PMID:17108473

  13. Clinical Experiences of Non-fusion Dynamic Stabilization Surgery for Adjacent Segmental Pathology after Lumbar Fusion

    PubMed Central

    Lee, Soo Eon; Kim, Hyun-Jib

    2016-01-01

    Background As an alternative to spinal fusion, non-fusion dynamic stabilization surgery has been developed, showing good clinical outcomes. In the present study, we introduce our surgical series, which involves non-fusion dynamic stabilization surgery for adjacent segment pathology (ASP) after lumbar fusion surgery. Methods Fifteen patients (13 female and 2 male, mean age of 62.1 years) who underwent dynamic stabilization surgery for symptomatic ASP were included and medical records, magnetic resonance images (MRI), and plain radiographs were retrospectively evaluated. Results Twelve of the 15 patients had the fusion segment at L4-5, and the most common segment affected by ASP was L3-4. The time interval between prior fusion and later non-fusion surgery was mean 67.0 months. The Visual Analog Scale and Oswestry Disability Index showed values of 7.4 and 58.5% before the non-fusion surgery and these values respectively declined to 4.2 and 41.3% postoperatively at 36 months (p=0.027 and p=0.018, respectively). During the mean 44.8 months of follow-up, medication of analgesics was also significantly reduced. The MRI grade for disc and central stenosis identified significant degeneration at L3-4, and similar disc degeneration from lateral radiographs was determined at L3-4 between before the prior fusion surgery and the later non-fusion surgery. After the non-fusion surgery, the L3-4 segment and the proximal segment of L2-3 were preserved in the disc, stenosis and facet joint whereas L1-2 showed disc degeneration on the last MRI (p=0.032). Five instances of radiologic ASP were identified, showing characteristic disc-space narrowing at the proximal segments of L1-2 and L2-3. However, no patient underwent additional surgery for ASP after non-fusion dynamic stabilization surgery. Conclusion The proposed non-fusion dynamic stabilization system could be an effective surgical treatment for elderly patients with symptomatic ASP after lumbar fusion. PMID:27162710

  14. Reduction in adjacent-segment degeneration after multilevel posterior lumbar interbody fusion with proximal DIAM implantation.

    PubMed

    Lu, Kang; Liliang, Po-Chou; Wang, Hao-Kuang; Liang, Cheng-Loong; Chen, Jui-Sheng; Chen, Tai-Been; Wang, Kuo-Wei; Chen, Han-Jung

    2015-08-01

    OBJECT Multilevel long-segment lumbar fusion poses a high risk for future development of adjacent-segment degeneration (ASD). Creating a dynamic transition zone with an interspinous process device (IPD) proximal to the fusion has recently been applied as a method to reduce the occurrence of ASD. The authors report their experience with the Device for Intervertebral Assisted Motion (DIAM) implanted proximal to multilevel posterior lumbar interbody fusion (PLIF) in reducing the development of proximal ASD. METHODS This retrospective study reviewed 91 cases involving patients who underwent 2-level (L4-S1), 3-level (L3-S1), or 4-level (L2-S1) PLIF. In Group A (42 cases), the patients received PLIF only, while in Group B (49 cases), an interspinous process device, a DIAM implant, was put at the adjacent level proximal to the PLIF construct. Bone resection at the uppermost segment of the PLIF was equally limited in the 2 groups, with preservation of the upper portion of the spinous process/lamina and the attached supraspinous ligament. Outcome measures included a visual analog scale (VAS) for low-back pain and leg pain and the Oswestry Disability Index (ODI) for functional impairment. Anteroposterior and lateral flexion/extension radiographs were used to evaluate the fusion status, presence and patterns of ASD, and mobility of the DIAM-implanted segment. RESULTS Solid interbody fusion without implant failure was observed in all cases. Radiographic ASD occurred in 20 (48%) of Group A cases and 3 (6%) of Group B cases (p < 0.001). Among the patients in whom ASD was identified, 9 in Group A and 3 in Group B were symptomatic; of these patients, 3 in Group A and 1 in Group B underwent a second surgery for severe symptomatic ASD. At 24 months after surgery, Group A patients fared worse than Group B, showing higher mean VAS and ODI scores due to symptoms related to ASD. At the final follow-up evaluations, as reoperations had been performed to treat symptomatic ASD in some

  15. New Classification for Clinically Symptomatic Adjacent Segment Pathology in Cervical Disc Disease

    PubMed Central

    2015-01-01

    Study Design Clinical adjacent segment pathology (CASP) is common after cervical disc surgery. A critical examination of 320 patients operated for cervical disc prolapse revealed that CASP can also occur in patients with congenital and degenerative fusion of cervical spine. This has not been studied in depth and there is a need for a practically applicable classification of CASP. Purpose To develop a new classification scheme of CASP. Overview of Literature A review of the literature did not reveal a practically applicable classification incorporating the occurrence of CASP in congenital and degenerative fusion cases. Methods This was a retrospective analysis of 320 patients operated (509 disc spaces) on for cervical disc prolapse. Cases (n=316) were followed-up for 3-11 years. Random sampling of 220 patients with postoperative magnetic resonance imaging (MRI) in 165 cases was analyzed. Results Six symptomatic CASP cases required resurgery (1.9%), eight cases involved MRI proven CASP with axial neck pain only and 13 patients were asymptomatic with radiological adjacent segment pathology (RASP). The frequency rate was 8.5% (27/316). Four cases of congenital or degenerative fusion of vertebra developed CASP requiring surgery. CASP is classified as primary or secondary follows. Primary A1 was congenital fusion of vertebra and primary A2 was degenerative fusion of the vertebra. Secondary, which was after cervical disc surgery, comprised B1 (RASP in asymptomatic patients), B2 (CASP in patients with axial neck pain), and B3 (CASP with myeloradiculopathy). B3 was subdivided into single-level CASP (B3a) and multiple-level CASP (B3b). Conclusions Symptomatic CASP requiring resurgery is infrequent. CASP can occur in patients with congenital and degenerative fusion of the cervical spine. A new classification for CASP along with treatment strategy is proposed. Patients in Primary CASP and B3 CASP require resurgery while others require only observation. PMID:26712514

  16. Biomechanical Analysis of Fusion Segment Rigidity Upon Stress at Both the Fusion and Adjacent Segments: A Comparison between Unilateral and Bilateral Pedicle Screw Fixation

    PubMed Central

    Kim, Ho-Joong; Kang, Kyoung-Tak; Chang, Bong-Soon; Lee, Choon-Ki; Kim, Jang-Woo

    2014-01-01

    Purpose The purpose of this study was to investigate the effects of unilateral pedicle screw fixation on the fusion segment and the superior adjacent segment after one segment lumbar fusion using validated finite element models. Materials and Methods Four L3-4 fusion models were simulated according to the extent of decompression and the method of pedicle screws fixation in L3-4 lumbar fusion. These models included hemi-laminectomy with bilateral pedicle screw fixation in the L3-4 segment (BF-HL model), total laminectomy with bilateral pedicle screw fixation (BF-TL model), hemi-laminectomy with unilateral pedicle screw fixation (UF-HL model), and total laminectomy with unilateral pedicle screw fixation (UF-TL model). In each scenario, intradiscal pressures, annulus stress, and range of motion at the L2-3 and L3-4 segments were analyzed under flexion, extension, lateral bending, and torsional moments. Results Under four pure moments, the unilateral fixation leads to a reduction in increment of range of motion at the adjacent segment, but larger motions were noted at the fusion segment (L3-4) in the unilateral fixation (UF-HL and UF-TL) models when compared to bilateral fixation. The maximal von Mises stress showed similar patterns to range of motion at both superior adjacent L2-3 segments and fusion segment. Conclusion The current study suggests that unilateral pedicle screw fixation seems to be unable to afford sufficient biomechanical stability in case of bilateral total laminectomy. Conversely, in the case of hemi-laminectomy, unilateral fixation could be an alternative option, which also has potential benefit to reduce the stress of the adjacent segment. PMID:25048501

  17. Older literature review of increased risk of adjacent segment degeneration with instrumented lumbar fusions

    PubMed Central

    Epstein, Nancy E.

    2016-01-01

    Background: Adjacent segment degeneration (ASD) following lumbar spine surgery occurs in up to 30% of cases, and descriptions of such changes are not new. Here, we review some of the older literature concerning the rate of ASD, typically more severe cephalad than caudad, and highly correlated with instrumented fusions. Therefore, for degenerative lumbar disease without frank instability, ASD would be markedly reduced by avoiding instrumented fusions. Methods: In a prior review, the newer literature regarding the frequency of ASD following lumbar instrumented fusions (e.g., transforaminal or posterior lumbar interbody fusions [TLIF/PLIF] fusions or occasionally, posterolateral fusions [PLFs]) was presented. Some studies cited an up to an 18.5% incidence of ASD following instrumented versus noninstrumented fusions/decompressions alone (5.6%). A review of the older literature similarly documents a higher rate of ASD following instrumented fusions performed for degenerative lumbar disease alone. Results: More frequent and more severe ASD follows instrumented lumbar fusions performed for degenerative lumbar disease without instability. Alternatively, this entity should be treated with decompressions alone or with noninstrumented fusions, without the addition of instrumentation. Conclusions: Too many studies assume that TLIF, PLIF, and even PLF instrumented fusions are the “gold standard of care” for dealing with degenerative disease of the lumbar spine without documented instability. It is time to correct that assumption, and reassess the older literature along with the new to confirm that decompression alone and noninstrumented fusion avoid significant morbidity and even potentially mortality attributed to unnecessary instrumentation. PMID:26904370

  18. Turbine nozzle stage having thermocouple guide tube

    DOEpatents

    Schotsch, Margaret Jones; Kirkpatrick, Francis Lawrence; Lapine, Eric Michael

    2002-01-01

    A guide tube is fixed adjacent opposite ends in outer and inner covers of a nozzle stage segment. The guide tube is serpentine in shape between the outer and inner covers and extends through a nozzle vane. An insert is disposed in the nozzle vane and has apertures to accommodate serpentine portions of the guide tube. Cooling steam is also supplied through chambers of the insert on opposite sides of a central insert chamber containing the guide tube. The opposite ends of the guide tube are fixed to sleeves, in turn fixed to the outer and inner covers.

  19. Outcomes of surgery for unstable odontoid fractures combined with instability of adjacent segments

    PubMed Central

    2014-01-01

    Background At present, traumatic atlantoaxial dislocation or C2-3 instability complicating odontoid fractures remains rarely reported. The aim of this study was to further investigate the surgical treatment strategies and curative effects for odontoid fractures combined with instability of adjacent segments. Methods This is a retrospective study of 12 patients (5 females and 7 males; age, 21–65 years) who underwent internal fixation for odontoid fractures (type II and shallow type III) and atlantoaxial instability in 6 cases, C2-3 instability in 4 cases, simultaneous C1-2 and C2-3 instability in 2 cases between January 2005 and June 2012. Accordingly, individualized surgeries were performed. Fracture healing and bone fusion were determined on X-ray scan. Upper limbs, lower limbs and sphincter functions were assessed using the Japanese Orthopaedic Association (JOA) score. Frankel grading system was used for the evaluation of neurological situation. Results Mean follow-up time of all 12 cases was 16.4 months (range, 12 to 48 months). Odontoid fracture healing was obtained in all patients within 9 months, and graft fusion was achieved within 6 months. JOA score was significantly improved from 6.3 ± 3.1 preoperatively to 11.1 ± 4.6 at 12 months after operation (P = 0.007), with 50.5 ± 25.7% recovery rate and 66.7% excellent and good rate. Except one patient still had Frankel grade B neurological injury at 12 months after surgery, the other patients improved their neurological situation (at 1 grade in Frankel scale). One patient developed wound fat liquefaction which resolved by changing the dressing. Cerebrospinal fluid leakage occurred in three patients, which resolved after the continuous drainage for 2 days. Conclusions According to the characteristics of odontoid fractures, the individualized operative procedure should be performed, resulting in high fracture healing rate, function recovery rate, and less, transient complications. PMID:25164238

  20. Segmenting time-lapse phase contrast images of adjacent NIH 3T3 cells.

    PubMed

    Chalfoun, J; Kociolek, M; Dima, A; Halter, M; Cardone, A; Peskin, A; Bajcsy, P; Brady, M

    2013-01-01

    We present a new method for segmenting phase contrast images of NIH 3T3 fibroblast cells that is accurate even when cells are physically in contact with each other. The problem of segmentation, when cells are in contact, poses a challenge to the accurate automation of cell counting, tracking and lineage modelling in cell biology. The segmentation method presented in this paper consists of (1) background reconstruction to obtain noise-free foreground pixels and (2) incorporation of biological insight about dividing and nondividing cells into the segmentation process to achieve reliable separation of foreground pixels defined as pixels associated with individual cells. The segmentation results for a time-lapse image stack were compared against 238 manually segmented images (8219 cells) provided by experts, which we consider as reference data. We chose two metrics to measure the accuracy of segmentation: the 'Adjusted Rand Index' which compares similarities at a pixel level between masks resulting from manual and automated segmentation, and the 'Number of Cells per Field' (NCF) which compares the number of cells identified in the field by manual versus automated analysis. Our results show that the automated segmentation compared to manual segmentation has an average adjusted rand index of 0.96 (1 being a perfect match), with a standard deviation of 0.03, and an average difference of the two numbers of cells per field equal to 5.39% with a standard deviation of 4.6%. PMID:23126432

  1. Long-Term Effects of Segmental Lumbar Spinal Fusion on Adjacent Healthy Discs: A Finite Element Study

    PubMed Central

    Srinivas, Gunti Ranga; Deb, Anindya; Kurnool, Goutham

    2016-01-01

    Study Design Experimental study. Purpose The aim of the study was to develop a finite element (FE) model to study the long-term effects of various types of lumbar spinal interventions on the discs adjacent to the fused segment. Overview of Literature Earlier FE studies have been limited to one particular type of fusion and comparative quantification of the adjacent disc stresses for different types of surgical interventions has not been reported. Methods A computer aided engineering (CAE) based approach using implicit FE analysis assessed the stresses in the lumbar discs adjacent to the fused segment following anterior and posterior lumbar spine fusions at one, two and three levels (with and without instrumentation). Results It was found that instrumentation and length of fusion were the most significant factors in increasing adjacent level stresses in the lumbar discs. Conclusions In the present study, a calibrated FE model that examined spinal interventions under similar loading and boundary conditions was used to provide quantitative data which would be useful for clinicians to understand the probable long-term effect of their choice of surgical intervention. PMID:27114758

  2. Precordial ST segment depression during acute inferior myocardial infarction: early thallium-201 scintigraphic evidence of adjacent posterolateral or inferoseptal involvement

    SciTech Connect

    Lew, A.S.; Weiss, A.T.; Shah, P.K.; Maddahi, J.; Peter, T.; Ganz, W.; Swan, H.J.; Berman, D.S.

    1985-02-01

    To investigate the myocardial perfusion correlates of precordial ST segment depression during acute inferior myocardial infarction, a rest thallium-201 scintigram and a closely timed 12 lead electrocardiogram were obtained within 6 hours of the onset of infarction in 44 patients admitted with their first acute inferior myocardial infarction. Thirty-six patients demonstrated precordial ST segment depression (group 1) and eight did not (group 2). A perfusion defect involving the inferior wall was present in all 44 patients. Additional perfusion defects of the adjacent posterolateral wall (n . 20), the ventricular septum (n . 9) or both (n . 6) were present in 35 of 36 patients from group 1 compared with only 1 of 8 patients from group 2 (p less than 0.001). There was no significant difference in the frequency of multivessel coronary artery disease or disease of the left anterior descending artery between group 1 and group 2 or between patients with and those without a thallium-201 perfusion defect involving the ventricular septum. Thus, precordial ST segment depression during an acute inferior myocardial infarction is associated with thallium-201 scintigraphic evidence of more extensive involvement of the adjacent posterolateral or inferoseptal myocardial segments, which probably reflects the extent and pattern of distribution of the artery of infarction, rather than the presence of coexistent multivessel coronary artery disease or disease of the left anterior descending artery.

  3. Failure of cervical arthroplasty in a patient with adjacent segment disease associated with Klippel-Feil syndrome

    PubMed Central

    Papanastassiou, Ioannis D; Baaj, Ali A; Dakwar, Elias; Eleraky, Mohammad; Vrionis, Frank D

    2011-01-01

    Cervical arthroplasty may be justified in patients with Klippel-Feil syndrome (KFS) in order to preserve cervical motion. The aim of this paper is to report an arthroplasty failure in a patient with KFS. A 36-year-old woman with KFS underwent two-level arthroplasty for adjacent segment disc degeneration. Anterior migration of the cranial prosthesis was encountered 5 months postoperatively and was successfully revised with anterior cervical fusion. Cervical arthroplasty in an extensively stiff and fused neck is challenging and may lead to catastrophic failure. Although motion preservation is desirable in KFS, the special biomechanical features may hinder arthroplasty. Fusion or hybrid constructs may represent more reasonable options, especially when multiple fused segments are present. PMID:21430874

  4. 2010 M=7.0 Haiti Earthquake Calculated to Increase Failure Stress on Adjacent Segments of the Enriquillo Fault and Adjacent Thrust Systems

    NASA Astrophysics Data System (ADS)

    Lin, Jian; Stein, Ross S.; Sevilgen, Volkan; Toda, Shinji

    2010-05-01

    We calculate that the Haiti earthquake increased the failure stress on the adjacent segments of the Enriquillo Fault and other thrust faults. Of particular concern is the segment on the Enriquillo Fault immediately to the east of the 12 January rupture. This fault section, which comes within 5 km of Port-au-Prince, is calculated to have been brought about 2-5 bars closer to failure. The inference of stress increase on this eastern section is relatively robust regardless of the specific source models used from available seismic and geodetic inversions. The next most loaded section on the Enriquillo Fault lies to the west of the 12 January rupture, where stress is calculated to have been brought about 1 bar closer to failure. The calculated stress increases on this western section, however, are more sensitive to the source models used in the calculation. Thus far we have tested several teleseismic and InSAR-based models, all of which assume slip occurred on a single north-dipping planar surface. If significant coseismic slip took place on a reverse fault at the western end of the 12 January rupture, these models will need further revision. Previous GPS measurements have shown tectonic loading of 7 ± 2 mm/yr on the Enriquillo Fault, yielding about 1.7 m of accumulated loading since large quakes last struck this region in 1751 and 1770. One or both of these appear to be coupled events separated by days to months, but it is unclear if these struck on the Enriquillo Fault. Thus, there is at least a possibility of future large quakes on these segments of the Enriquillo Fault. We also calculate stress increase of about 0.1-0.5 bars on some surrounding thrust faults, as well as a small increase of 0.05 bars on the Septentrional Fault between Port-de-Paix and Cap-Haitien, which lie 155 km north of the 12 January rupture. Preliminary models are available at http://pubs.usgs.gov/of/2010/1019/.

  5. Hook nozzle arrangement for supporting airfoil vanes

    DOEpatents

    Shaffer, J.E.; Norton, P.F.

    1996-02-20

    A gas turbine engine`s nozzle structure includes a nozzle support ring, a plurality of shroud segments, and a plurality of airfoil vanes. The plurality of shroud segments are distributed around the nozzle support ring. Each airfoil vane is connected to a corresponding shroud segment so that the airfoil vanes are also distributed around the nozzle support ring. Each shroud segment has a hook engaging the nozzle support ring so that the shroud segments and corresponding airfoil vanes are supported by the nozzle support ring. The nozzle support ring, the shroud segments, and the airfoil vanes may be ceramic. 8 figs.

  6. Hook nozzle arrangement for supporting airfoil vanes

    DOEpatents

    Shaffer, James E.; Norton, Paul F.

    1996-01-01

    A gas turbine engine's nozzle structure includes a nozzle support ring, a plurality of shroud segments, and a plurality of airfoil vanes. The plurality of shroud segments are distributed around the nozzle support ring. Each airfoil vane is connected to a corresponding shroud segment so that the airfoil vanes are also distributed around the nozzle support ring. Each shroud segment has a hook engaging the nozzle support ring so that the shroud segments and corresponding airfoil vanes are supported by the nozzle support ring. The nozzle support ring, the shroud segments, and the airfoil vanes may be ceramic.

  7. Magnetic resonance imaging on disc degeneration changes after implantation of an interspinous spacer and fusion of the adjacent segment

    PubMed Central

    Liu, Xiaokang; Liu, Yingjie; Lian, Xiaofeng; Xu, Jianguang

    2015-01-01

    The aim of the study was to investigate the changes of the lumbar intervertebral disc degeneration by magnetic resonance imaging (MRI) after the implantation of interspinous device and the fusion of the adjacent segment. A total of 62 consecutive patients suffering L5/S1 lumbar disc herniation (LDH) with concomitant disc space narrowing or low-grade instability up to 5 mm translational slip in L5/S1 level were treated with lumbar interbody fusion (LIF) via posterior approach. Thirty-four of these patients (Coflex group) received an additional implantation of the interspinous spacer device (Coflex™) in the level L4/L5, while the rest of 28 patients (fusion group) underwent the fusion surgery alone. Clinical and radiographic examinations were performed at pre- and postoperative visits to compare the clinical outcomes and the changes of the L4/L5 vertebral disc degeneration on MRI in both Coflex and fusion group. Although both Coflex and fusion group showed improvements of the clinical outcomes assessed by the Oswestry Disability Index (ODI) after surgery, patients in Coflex group had more significant amelioration (P < 0.05) compared to fusion group. During follow up, the postoperative disc degeneration changes in Coflex group assessed by the relative signal intensity (RSI) differed from those in fusion group (P < 0.05). The supplemental implantation of Coflex™ after the fusion surgery could delay the disc degeneration of the adjacent segment. PMID:26131210

  8. Biomechanical Analysis of the Proximal Adjacent Segment after Multilevel Instrumentation of the Thoracic Spine: Do Hooks Ease the Transition?

    PubMed

    Metzger, Melodie F; Robinson, Samuel T; Svet, Mark T; Liu, John C; Acosta, Frank L

    2016-06-01

    Study Design Biomechanical cadaveric study. Objective Clinical studies indicate that using less-rigid fixation techniques in place of the standard all-pedicle screw construct when correcting for scoliosis may reduce the incidence of proximal junctional kyphosis and improve patient outcomes. The purpose of this study is to investigate whether there is a biomechanical advantage to using supralaminar hooks in place of pedicle screws at the upper-instrumented vertebrae in a multilevel thoracic construct. Methods T7-T12 spines were biomechanically tested: (1) intact; (2) following a two-level pedicles screw fusion from T9 to T11; and after proximal extension of the fusion to T8-T9 with (3) bilateral supra-laminar hooks, (4) a unilateral hook + unilateral screw hybrid, or (5) bilateral pedicle screws. Specimens were nondestructively loaded while three-dimensional kinematics and intradiscal pressure at the supra-adjacent level were recorded. Results Supra-adjacent hypermobility was reduced when bilateral hooks were used in place of pedicle screws at the upper-instrumented level, with statistically significant differences in lateral bending and torsion (p < 0.05 and p < 0.001, respectively). Disk pressures in the supra-adjacent segment were not statistically different among top-off techniques. Conclusions The use of supralaminar hooks at the top of a multilevel posterior fusion construct reduces the stress at the proximal uninstrumented motion segment. Although further data is needed to provide a definitive link to the clinical occurrence of PJK, this in vitro study demonstrates the potential benefit of "easing" the transition between the stiff instrumented spine and the flexible native spine and is the first to demonstrate these results with laminar hooks. PMID:27190735

  9. Risk of adjacent-segment disease requiring surgery after short lumbar fusion: results of the French Spine Surgery Society Series.

    PubMed

    Scemama, Caroline; Magrino, Baptiste; Gillet, Philippe; Guigui, Pierre

    2016-07-01

    OBJECTIVE Adjacent-segment disease (ASD) is an increasingly problematic complication following lumbar fusion surgery. The purpose of the current study was to determine the risk of ASD requiring surgical treatment after short lumbar or lumbosacral fusion. Primary spinal disease and surgical factors associated with an increased risk of revision were also investigated. METHODS This was a retrospective cohort study using the French Spine Surgery Society clinical data that included 3338 patients, with an average follow-up duration of 7 years (range 4-10 years). Clinical ASD requiring surgery was the principal judgment criterion; the length of follow-up time and initial spinal disease were also recorded. Kaplan-Meier survival analysis was performed. The correlation between primary spinal disease and surgery with an increased risk of revision was investigated. RESULTS During the follow-up period, 186 patients required revision surgery for ASD (5.6%). The predicted risk of ASD requiring revision surgery was 1.7% (95% CI 1.3%-2.2%) at 2 years, 3.8% (95% CI 4.9%-6.7%) at 4 years, 5.7% (95% CI 4.9%-6.7%) at 6 years, and 9% (95% CI 8.7%-10.6%) at 8 years. Initial spinal disease affected the risk of ASD requiring surgery (p = 0.0003). The highest risk was observed for degenerative spondylolisthesis. CONCLUSIONS ASD requiring revision surgery was predicted in 5.6% of patients 7 years after index short lumbar spinal fusion in the French Spine Surgery Society retrospective series. An increased risk of ASD requiring revision surgery associated with initial spinal disease showed the significance of the influence of natural degenerative history on adjacent-segment pathology. PMID:26967992

  10. Ceramic turbine nozzle

    DOEpatents

    Shaffer, James E.; Norton, Paul F.

    1996-01-01

    A turbine nozzle and shroud assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and being attached to conventional metallic components. The metallic components having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine nozzle vane assembly. The turbine nozzle vane assembly includes a plurality of segmented vane defining a first vane segment and a second vane segment. Each of the first and second vane segments having a vertical portion. Each of the first vane segments and the second vane segments being positioned in functional relationship one to another within a recess formed within an outer shroud and an inner shroud. The turbine nozzle and shroud assembly provides an economical, reliable and effective ceramic component having a preestablished rate of thermal expansion being less than the preestablished rate of thermal expansion of the other component.

  11. Ceramic turbine nozzle

    DOEpatents

    Shaffer, J.E.; Norton, P.F.

    1996-12-17

    A turbine nozzle and shroud assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and being attached to conventional metallic components. The metallic components have a preestablished rate of thermal expansion greater than the preestablished rate of thermal expansion of the turbine nozzle vane assembly. The turbine nozzle vane assembly includes a plurality of segmented vane defining a first vane segment and a second vane segment, each of the first and second vane segments having a vertical portion, and each of the first vane segments and the second vane segments being positioned in functional relationship one to another within a recess formed within an outer shroud and an inner shroud. The turbine nozzle and shroud assembly provides an economical, reliable and effective ceramic component having a preestablished rate of thermal expansion being less than the preestablished rate of thermal expansion of the other component. 4 figs.

  12. Nozzle insert for mixed mode fuel injector

    DOEpatents

    Lawrence, Keith E.

    2006-11-21

    A fuel injector includes a homogenous charge nozzle outlet set and a conventional nozzle outlet set controlled respectively, by first and second needle valve members. The homogeneous charged nozzle outlet set is defined by a nozzle insert that is attached to an injector body, which defines the conventional nozzle outlet set. The nozzle insert is a one piece metallic component with a large diameter segment separated from a small diameter segment by an annular engagement surface. One of the needle valve members is guided on an outer surface of the nozzle insert, and the nozzle insert has an interference fit attachment to the injector body.

  13. Causes of long-term landscape evolution of "passive" margins and adjacent continental segments at the South Atlantic Ocean.

    NASA Astrophysics Data System (ADS)

    Glasmacher, Ulrich Anton; Hackspacher, Peter C.

    2013-04-01

    During the last 10 years research efforts have been devoted to understand the coupling between tectonic and surface processes in the formation of recent topography. Quantification of the rate at which landforms adapt to a changing tectonic, heat flow, and climate environment in the long term has become an important research object and uses intensively data revealed by low-temperature thermochronology, terrigenous cosmogenic nuclides, and geomorphological analyses. The influence of endogenic forces such as mantle processes as one of the causes for "Dynamic Topography Evolution" have been explored in a few studies, recently. In addition, the increased understanding how change in surface topography, and change in the amount of downward moving cold surface water caused by climate change affects warping isotherms in the uppermost crust allows further interpretation of low-temperature thermochronological data. "Passive" continental margins and adjacent continental segments especially at the South Atlantic ocean are perfect locations to quantify exhumation and uplift rates, model the long-term landscape evolution, and provide information on the influence of mantle processes on a longer time scale. This climate-continental margin-mantle process-response system is caused by the interaction between endogenic and exogenic forces that are related to the mantle-process driven rift - drift - "passive" continental margin evolution of the South Atlantic, and the climate change since the Early/Late Cretaceous climate maximum. Furthermore, the influence of major transform faults (also called: transfer zones, Fracture Zones (FZ)) on the long-term evolution of "passive" continental margins is still very much in debate. The presentation will provide insight in possible causes for the differentiated long-term landscape evolution along the South Atlantic Ocean.

  14. Decisive factor in increase of loading at adjacent segments after lumbar fusion: operative technique, pedicle screws, or fusion itself: biomechanical analysis using finite element

    NASA Astrophysics Data System (ADS)

    Park, Joon-Hee; Kim, Ho-Joong; Kang, Kyoung-Tak; Kim, Ka-yeon; Chun, Heoung-Jae; Moon, Seong-Hwan; Lee, Hwan-Mo

    2010-03-01

    The aim of this study is to investigate the change in biomechanical milieu following removal of pedicle screws or removal of spinous process with posterior ligament complex in instrumented single level lumbar arthrodesis. We developed and validated a finite element model (FEM) of the intact lumbar spine (L2-4). Four scenarios of L3-4 lumbar fusion were simulated: posterolateral fusion (PLF) at L3-4 using pedicle screw system with preservation of PLC (Pp WiP), L3-4 lumbar posterolateral fusion state after removal of pedicle screw system with preservation of PLC (Pp WoP), L3-4 using pedicle screw system without preservation PLC (Sp WiP), L3-4 lumbar posterolateral fusion state after removal of pedicle screw system without preservation of PLC (Sp WoP). For these models, we investigated the range of motion and maximal Von mises stress of disc in all segments under various moments. All fusion models demonstrated increase in range of motion at adjacent segments compared to the intact model.For the four fusion models, the WiP model s P had the largest increase in range of motion at each adjacent segment. This study demonstrated that removal of pedicle screw system and preservation of PLC after complete lumbar spinal fusion could reduce the stress of adjacent segments synergistically and might have beneficial effects in preventing ASD.

  15. Decisive factor in increase of loading at adjacent segments after lumbar fusion: operative technique, pedicle screws, or fusion itself: biomechanical analysis using finite element

    NASA Astrophysics Data System (ADS)

    Park, Joon-Hee; Kim, Ho-Joong; Kang, Kyoung-Tak; Kim, Ka-Yeon; Chun, Heoung-Jae; Moon, Seong-Hwan; Lee, Hwan-Mo

    2009-12-01

    The aim of this study is to investigate the change in biomechanical milieu following removal of pedicle screws or removal of spinous process with posterior ligament complex in instrumented single level lumbar arthrodesis. We developed and validated a finite element model (FEM) of the intact lumbar spine (L2-4). Four scenarios of L3-4 lumbar fusion were simulated: posterolateral fusion (PLF) at L3-4 using pedicle screw system with preservation of PLC (Pp WiP), L3-4 lumbar posterolateral fusion state after removal of pedicle screw system with preservation of PLC (Pp WoP), L3-4 using pedicle screw system without preservation PLC (Sp WiP), L3-4 lumbar posterolateral fusion state after removal of pedicle screw system without preservation of PLC (Sp WoP). For these models, we investigated the range of motion and maximal Von mises stress of disc in all segments under various moments. All fusion models demonstrated increase in range of motion at adjacent segments compared to the intact model.For the four fusion models, the WiP model s P had the largest increase in range of motion at each adjacent segment. This study demonstrated that removal of pedicle screw system and preservation of PLC after complete lumbar spinal fusion could reduce the stress of adjacent segments synergistically and might have beneficial effects in preventing ASD.

  16. Radiologic Findings and Risk Factors of Adjacent Segment Degeneration after Anterior Cervical Discectomy and Fusion : A Retrospective Matched Cohort Study with 3-Year Follow-Up Using MRI

    PubMed Central

    So, Wan-Soo; Ku, Min-Geun; Kim, Sang-Hyeon; Kim, Dong-Won; Lee, Byung-Hun

    2016-01-01

    Objective The purpose of this study was to figure out the radiologic findings and risk factors related to adjacent segment degeneration (ASD) after anterior cervical discectomy and fusion (ACDF) using 3-year follow-up radiography, computed tomography (CT), and magnetic resonance image (MRI). Methods A retrospective matched comparative study was performed for 64 patients who underwent single-level ACDF with a cage and plate. Radiologic parameters, including upper segment range of motion (USROM), lower segment range of motion (LSROM), upper segment disc height (UDH), and lower segment disc height (LDH), clinical outcomes assessed with neck and arm visual analogue scale (VAS), and risk factors were analyzed. Results Patients were categorized into the ASD (32 patients) and non-ASD (32 patients) group. The decrease of UDH was significantly greater in the ASD group at each follow-up visit. At 36 months postoperatively, the difference for USROM value from the preoperative one significantly increased in the ASD group than non-ASD group. Preoperative other segment degeneration was significantly associated with the increased incidence of ASD at 36 months. However, pain intensity for the neck and arm was not significantly different between groups at any post-operative follow-up visit. Conclusion The main factor affecting ASD is preoperative other segment degeneration out of the adjacent segment. In addition, patients over the age of 50 are at higher risk of developing ASD. Although there was definite radiologic degeneration in the ASD group, no significant difference was observed between the ASD and non-ASD groups in terms of the incidence of symptomatic disease. PMID:26962418

  17. REACTOR NOZZLE ASSEMBLY

    DOEpatents

    Capuder, F.C.; Dearwater, J.R.

    1959-02-10

    An improved nozzle assembly useful in a process for the direct reduction of uranium hexafluoride to uranium tetrafluoride by means of dissociated ammonia in a heated reaction vessel is descrlbed. The nozzle design provides for intimate mixing of the two reactants and at the same time furnishes a layer of dissociated ammonia adjacent to the interior wall of the reaction vessel, thus preventing build-up of the reaction product on the vessel wall.

  18. Ceramic Cerami Turbine Nozzle

    DOEpatents

    Boyd, Gary L.

    1997-04-01

    A turbine nozzle vane assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and being attached to conventional metallic components. The metallic components having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine nozzle vane assembly. The turbine nozzle vane assembly includes an outer shroud and an inner shroud having a plurality of horizontally segmented vanes therebetween being positioned by a connecting member positioning segmented vanes in functional relationship one to another. The turbine nozzle vane assembly provides an economical, reliable and effective ceramic component having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the other component.

  19. Atomizing nozzle and process

    DOEpatents

    Anderson, Iver E.; Figliola, Richard S.; Molnar, Holly M.

    1993-07-20

    High pressure atomizing nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt atomization. The atomizing nozzle is especially useful in atomizing rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum magnetic properties.

  20. Atomizing nozzle and process

    DOEpatents

    Anderson, Iver E.; Figliola, Richard S.; Molnar, Holly M.

    1992-06-30

    High pressure atomizing nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt atomization. The atomizing nozzle is especially useful in atomizing rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum magnetic properties.

  1. Improvement in chronic low back pain in an aviation crash survivor with adjacent segment disease following flexion distraction therapy: a case study

    PubMed Central

    Greenwood, Dean M.

    2012-01-01

    Objective The purpose of this case study is to describe the chiropractic management of chronic low back pain in a patient with adjacent segment disease. Clinical Features The patient was a 30-year-old man with a 3-year history of chronic nonspecific low back pain following a lumbar disk herniation. Two years before this incident, he had severe lumbar fractures and cauda equina injury due to an aviation accident that required multilevel lumbar fusion surgery, vertebrectomy, and cage reconstruction. Intervention and Outcome The patient received chiropractic management using Cox Flexion Distraction over a 4-week period. A complete reduction of symptoms to 0/10 on a verbal numerical rating scale was achieved within 4 weeks. At 3 months, the patient was able to work 8 to 9 hours per day in his dental practice with no pain. At 9 months, the patient continued to report a complete reduction of symptoms. Conclusions This report describes the successful management of a patient with chronic low back pain associated with adjacent segment disease using Cox Flexion Distraction protocols. PMID:23843764

  2. High mass throughput particle generation using multiple nozzle spraying

    DOEpatents

    Pui, David Y. H.; Chen, Da-Ren

    2015-06-09

    Spraying apparatus and methods that employ multiple nozzle structures for producing multiple sprays of particles, e.g., nanoparticles, for various applications, e.g., pharmaceuticals, are provided. For example, an electrospray dispensing device may include a plurality of nozzle structures, wherein each nozzle structure is separated from adjacent nozzle structures by an internozzle distance. Sprays of particles are established from the nozzle structures by creating a nonuniform electrical field between the nozzle structures and an electrode electrically isolated therefrom.

  3. High mass throughput particle generation using multiple nozzle spraying

    DOEpatents

    Pui, David Y.H.; Chen, Da-Ren

    2004-07-20

    Spraying apparatus and methods that employ multiple nozzle structures for producing multiple sprays of particles, e.g., nanoparticles, for various applications, e.g., pharmaceuticals, are provided. For example, an electrospray dispensing device may include a plurality of nozzle structures, wherein each nozzle structure is separated from adjacent nozzle structures by an internozzle distance. Sprays of particles are established from the nozzle structures by creating a nonuniform electrical field between the nozzle structures and an electrode electrically isolated therefrom.

  4. High mass throughput particle generation using multiple nozzle spraying

    DOEpatents

    Pui, David Y. H.; Chen, Da-Ren

    2009-03-03

    Spraying apparatus and methods that employ multiple nozzle structures for producing multiple sprays of particles, e.g., nanoparticles, for various applications, e.g., pharmaceuticals, are provided. For example, an electrospray dispensing device may include a plurality of nozzle structures, wherein each nozzle structure is separated from adjacent nozzle structures by an internozzle distance. Sprays of particles are established from the nozzle structures by creating a nonuniform electrical field between the nozzle structures and an electrode electrically isolated therefrom.

  5. Cervical anterior hybrid technique with bi-level Bryan artificial disc replacement and adjacent segment fusion for cervical myelopathy over three consecutive segments.

    PubMed

    Chen, Jiang; Xu, Lin; Jia, Yu-Song; Sun, Qi; Li, Jin-Yu; Zheng, Chen-Ying; Bai, Chun-Xiao; Yu, Qin-Sheng

    2016-05-01

    This study aimed to assess the preliminary clinical efficacy and feasibility of the hybrid technique for multilevel cervical myelopathy. Considering the many shortcomings of traditional treatment methods for multilevel cervical degenerative myelopathy, hybrid surgery (bi-level Bryan artificial disc [Medtronic Sofamor Danek, Memphis, TN, USA] replacement and anterior cervical discectomy and fusion) should be considered. Between March 2006 and November 2012, 108 patients (68 men and 40 women, average age 45years) underwent hybrid surgery. Based on the Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI), and Odom's criteria, the clinical symptoms and neurological function before and after surgery were evaluated. Mean surgery duration was 90minutes, with average blood loss of 30mL. Mean follow-up duration was 36months. At the final follow-up, the mean JOA (± standard deviation) scores were significantly higher compared with preoperative values (15.08±1.47 versus 9.18±1.22; P<0.01); meanwhile, NDI values were markedly decreased (12.32±1.03 versus 42.68±1.83; P<0.01). Using Odom's criteria, the clinical outcomes were rated as excellent (76 patients), good (22 patients), fair (six patients), and poor (four patients). These findings indicate that the hybrid method provides an effective treatment for cervical myelopathy over three consecutive segments, ensuring a good clinical outcome. PMID:26758702

  6. Airfoil nozzle and shroud assembly

    DOEpatents

    Shaffer, James E.; Norton, Paul F.

    1997-01-01

    An airfoil and nozzle assembly including an outer shroud having a plurality of vane members attached to an inner surface and having a cantilevered end. The assembly further includes a inner shroud being formed by a plurality of segments. Each of the segments having a first end and a second end and having a recess positioned in each of the ends. The cantilevered end of the vane member being positioned in the recess. The airfoil and nozzle assembly being made from a material having a lower rate of thermal expansion than that of the components to which the airfoil and nozzle assembly is attached.

  7. Airfoil nozzle and shroud assembly

    DOEpatents

    Shaffer, J.E.; Norton, P.F.

    1997-06-03

    An airfoil and nozzle assembly are disclosed including an outer shroud having a plurality of vane members attached to an inner surface and having a cantilevered end. The assembly further includes a inner shroud being formed by a plurality of segments. Each of the segments having a first end and a second end and having a recess positioned in each of the ends. The cantilevered end of the vane member being positioned in the recess. The airfoil and nozzle assembly being made from a material having a lower rate of thermal expansion than that of the components to which the airfoil and nozzle assembly is attached. 5 figs.

  8. [TREATMENT OF POST-SPONDYLODESIS, ADJACENT-SEGMENT DISEASE WITH MINIMALLY INVASIVE, ANTEROLATERAL SURGERY ON THE LUMBAR SPINE: IS THERE IS NO NEED FOR DORSAL OPERATION?].

    PubMed

    Schwarcz, Attila; Szakály, Péter; Büki, András; Dóczi, Tamás

    2015-07-30

    Adjacent segment disease (ASD) occurs with a probability of 30% in the lumbar spine following spinal fusion surgery. Usually advanced degenerative changes happen cranially to the fused lumbar segment. Thus, secondary spinal instability, stenosis, spodylolisthesis, foraminal stenosis can lead to the recurrence of the pain not always amenable to conservative measures. A typical surgical solution to treat ASD consists of posterior revision surgery including decompression, change or extension of the instrumentation and fusion to the rostral level. It results in a larger operation with considerable risk of complications. We present a typical case of ASD treated surgically with a new minimally invasive method not yet performed in Hungary. We use anterolateral abdominal muscle splitting approach to reach the lumbar spine through the retroperitoneum. A discectomy is performed by retracting the psoas muscle dorsally. The intervertebral bony fusion is achieved by implanting a cage with large volume that is stuffed with autologous bone or tricalcium phosphate. A cage with large volume results in excellent annulus fibrosus tension, immediate stability and provides large surface for bony fusion. A stand-alone cage construct can be supplemented with lateral screw/rod/plate fixation. The advantage of the new technique for the treatment of ASD includes minimal blood loss, short operation time, significantly less postoperative pain and much lower complication rate. PMID:26380422

  9. Variable area exhaust nozzle

    NASA Technical Reports Server (NTRS)

    Johnston, E. A. (Inventor)

    1979-01-01

    An exhaust nozzle for a gas turbine engine comprises a number of arcuate flaps pivotally connected to the trailing edge of a cylindrical casing which houses the engine. Seals disposed within the flaps are spring biased and extensible beyond the side edges of the flaps. The seals of adjacent flaps are maintained in sealing engagement with each other when the flaps are adjusted between positions defining minimum nozzle flow area and the cruise position. Extensible, spring biased seals are also disposed within the flaps adjacent to a supporting pylon to thereby engage the pylon in a sealing arrangement. The flaps are hinged to the casing at the central portion of the flaps' leading edges and are connected to actuators at opposed outer portions of the leading edges to thereby maximize the mechanical advantage in the actuation of the flaps.

  10. Adjacent segment disease after anterior cervical discectomy and fusion: Incidence and clinical outcomes of patients requiring anterior versus posterior repeat cervical fusion

    PubMed Central

    Bydon, Mohamad; Xu, Risheng; De la Garza-Ramos, Rafael; Macki, Mohamed; Sciubba, Daniel M.; Wolinsky, Jean-Paul; Witham, Timothy F.; Gokaslan, Ziya L.; Bydon, Ali

    2014-01-01

    Background: Adjacent segment disease (ASD) is a well-recognized long-term outcome in patients with degenerative disease of the spine. In this manuscript, we focus on the development in ASD in patients who have undergone a prior anterior cervical discectomy and fusion (ACDF). Methods: Patient data were collected via clinical notes and patient interviews. Patients were followed for an average of 92.4 ± 72.6 months after the index ACDF. Results: Of the 108 patients who underwent revision surgery due to symptomatic ASD, 77 patients underwent re-do ACDF, while 31 patients had posterior fusion surgery. Patients were more likely to be operated on posteriorly if they were older (P = 0.0115), male (P = 0.006), or had a higher number of cervical vertebral segments fused during the index ACDF (P = 0.013). These patients were statistically also more likely to exhibit myelopathic symptoms (P = 0.0053), and usually had worse neurologic function as assessed on the Nurick (P = 0.0005) and ASIA scales (P = 0.0020). Postoperatively, patients receiving anterior revision surgeries had higher rates of recurrent radiculopathy (P = 0.0425) and higher recurrence of ASD compared with patients fused posteriorly (P < 0.0001). Conclusions: Patients undergoing an anterior revision surgery for ASD after ACDF have higher rates of postoperative radiculopathy and redevelopment of ASD when compared with posteriorly approached patients. Patients receiving posterior revision surgery had higher intraoperative blood loss, hospitalizations, and postoperative complications such as wound infections and discharge to rehabilitation, but had a statistically lower chance of redevelopment of ASD requiring secondary revision surgery. This may be due to the fact that posterior revision surgeries involved more levels fused. This study provides one of the longest and most comprehensive follow-ups of this challenging patient population. Prospective studies comparing surgical approaches and techniques are needed to

  11. Aircraft Engine Exhaust Nozzle System for Jet Noise Reduction

    NASA Technical Reports Server (NTRS)

    Thomas, Russell H. (Inventor); Czech, Michael J. (Inventor); Elkoby, Ronen (Inventor)

    2014-01-01

    The aircraft exhaust engine nozzle system includes a fan nozzle to receive a fan flow from a fan disposed adjacent to an engine disposed above an airframe surface of the aircraft, a core nozzle disposed within the fan nozzle and receiving an engine core flow, and a pylon structure connected to the core nozzle and structurally attached with the airframe surface to secure the engine to the aircraft.

  12. Segments.

    ERIC Educational Resources Information Center

    Zemsky, Robert; Shaman, Susan; Shapiro, Daniel B.

    2001-01-01

    Presents a market taxonomy for higher education, including what it reveals about the structure of the market, the model's technical attributes, and its capacity to explain pricing behavior. Details the identification of the principle seams separating one market segment from another and how student aspirations help to organize the market, making…

  13. Double-level cervical total disc replacement for adjacent segment disease: is it a useful treatment? Description of late onset heterotopic ossification and review of the literature.

    PubMed

    Barbagallo, G M V; Certo, F; Visocchi, M; Sciacca, G; Albanese, V

    2014-01-01

    We report a rare case of double-level adjacent segment disease (ASD), occurring ten years later an anterior cervical discectomy (ACD) without fusion, treated by cervical arthroplasty, highlighting the outcome at long-term follow-up and focusing on heterotopic ossification. In 1995 a 25-year-old man satisfactorily underwent ACD at C4/C5. At that time MRI also showed signs of degenerative disc disease (DDD) at C3/C4 and C5/C6. Ten years later, a new MRI scan showed a large C3/C4 and a smaller C5/C6 soft disc hernia together with spondylotic changes at the level above and below the site of the first surgery. At C4/C5 imaging revealed a kyphotic stable "pseudoarthrosis" with anterior bridging osteophyte. The patient underwent double-level arthroplasty with ProDisc-C. Clinical and radiological outcome was satisfactory. 3 and 5 years after surgery, X-rays and CT scan documented the progressive development of heterotopic ossification, with gradual reduction of range of motion. A late onset heterotopic ossification can neutralize the theoretical advantages of cervical arthroplasty, which should be considered an effective surgical option only in selected cases. ACDF and restoration of normal lordosis can be a viable alternative in cervical revision surgery, as motion preservation can not be always mantained for a long time. PMID:24825036

  14. Nozzle seal

    DOEpatents

    Herman, Richard Frederick

    1977-10-25

    In an illustrative embodiment of the invention, a nuclear reactor pressure vessel, having an internal hoop from which the heated coolant emerges from the reactor core and passes through to the reactor outlet nozzles, is provided with sealing members operatively disposed between the outlet nozzle and the hoop. The sealing members are biased against the pressure vessel and the hoop and are connected by a leak restraining member establishing a leak-proof condition between the inlet and outlet coolants in the region about the outlet nozzle. Furthermore, the flexible responsiveness of the seal assures that the seal will not structurally couple the hoop to the pressure vessel.

  15. Nozzle development

    SciTech Connect

    Dodge, F.T.; Dodge, L.G.; Johnson, J.E.

    1989-06-01

    The objective of this program has been the development of experimental techniques and data processing procedures to allow for the characterization of multi-phase fuel nozzles using laboratory tests. Test results were to be used to produce a single value coefficient-of-performance that would predict the performance of the fuel nozzles independent of system application. Several different types of fuel nozzles capable of handling multi-phase fuels have been characterized for: (a) fuel flow rate versus delivery pressure, (b) fuel-air ratio throughout the fuel spray or plume and the effective cone angle of the injector, and (c) fuel drop- or particle-size distribution as a function of fluid properties. Fuel nozzles which have been characterized on both single-phase liquids and multi-phase liquid-solid slurries include a variable-film-thickness nozzle, a commercial coal-water slurry (CWS) nozzle, and four diesel injectors of different geometries (tested on single-phase fluids only). Multi-phase mixtures includes CWS with various coal loadings, surfactant concentrations, and stabilizer concentrations, as well as glass-bead water slurries with stabilizing additives. Single-phase fluids included glycerol-water mixtures to vary the viscosity over a range of 1 to 1500 cP, and alcohol-water mixtures to vary the surface tension from about 22 to 73 dyne/cm. In addition, tests were performed to characterize straight-tube gas-solid nozzles using two differences size distributions of glass beads in air. Standardized procedures have been developed for processing measurements of spray drop-size characteristics and the overall cross-section average drop or particle size. 43 refs., 60 figs., 7 tabs.

  16. Ultrasonic flow nozzle cleaning apparatus

    SciTech Connect

    Fridsma, D.E.; Silvestri, G.J. Jr.; Twerdochlib, M.

    1992-06-23

    This patent describes an ultrasonic cleaning apparatus for a venturi flow measuring nozzle mounted in a pipe of a steam power plant and having an inlet, venturi throat, and an outlet, the pipe and nozzle having fluid flowing therethrough, the cleaning occurring while the fluid is flowing. It comprises first ultrasonic transducer means mounted to connect to the inside of the pipe, disposed adjacent the inlet of the venturi flow nozzle and the means being in direct contact with the fluid flowing through the pipe for transmitting ultrasonic waves directly into and thereby exciting the fluid flowing through the venturi flow nozzle; and control means coupled to the first ultrasonic transducer means for activating the first ultrasonic transducer means.

  17. Nozzle seal

    DOEpatents

    Groff, Russell Dennis; Vatovec, Richard John

    1978-06-11

    In an illustrative embodiment of the invention, a nuclear reactor pressure vessel, having an internal hoop from which the heated coolant emerges from the reactor core and passes through to the reactor outlet nozzles, is provided with annular sealing members operatively disposed between the outlet nozzle and the hoop and partly within a retaining annulus formed in the hoop. The sealing members are biased against the pressure vessel and the hoop and one of the sealing members is provided with a piston type pressure ring sealing member which effectively closes the path between the inlet and outlet coolants in the region about the outlet nozzle establishing a leak-proof condition. Furthermore, the flexible responsiveness of the seal assures that the seal will not structurally couple the hoop to the pressure vessel.

  18. Sandblasting nozzle

    NASA Technical Reports Server (NTRS)

    Perkins, G. S.; Pawlik, E. V.; Phillips, W. M. (Inventor)

    1981-01-01

    A nozzle for use with abrasive and/or corrosive materials is formed of sintered ceramic compositions having high temperature oxidation resistance, high hardness and high abrasion and corrosion resistance. The ceramic may be a binary solid solution of a ceramic oxide and silicon nitride, and preferably a ternary solid solution of a ceramic oxide, silicon nitride and aluminum nitride. The ceramic oxide is selected from a group consisting of Al2O3, Y2O3 and Cr2O3, or mixtures of those compounds. Titanium carbide particles are dispersed in the ceramic mixture before sintering. The nozzles are encased for protection from external forces while in use by a metal or plastic casing.

  19. Line drawing of anomaly discovered in redesigned shuttle motor nozzle

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Line drawing titled 'DM-9 Case-to-Nozzle Joint' shows anomaly discovered in redesigned shuttle motor nozzle. The second full-duration test firing of NASA's redesigned Space Shuttle solid rocket motor (SRM), designated DM-9, was conducted 12-23-87 at Morton Thiokol's Wasatch facility in Utah. A post-test examination of the motor has revealed an anomaly in one nozzle component. Material was discovered missing from the nozzle outer boot ring, a large carbon phenolic composite ring used to anchor one end of the flexible boot that allows the nozzle to move and 'steer' the vehicle. About one-third of the missing 160 degrees of missing ring material was found adjacent to the forward nozzle section inside the motor. This diagram shows the location of the nozzle joint on an assembled SRM, and points out the shaded location of the outer boot ring that circles the motor within the nozzle joint.

  20. Fuel nozzle assembly

    DOEpatents

    Johnson, Thomas Edward; Ziminsky, Willy Steve; Lacey, Benjamin Paul; York, William David; Stevenson, Christian Xavier

    2011-08-30

    A fuel nozzle assembly is provided. The assembly includes an outer nozzle body having a first end and a second end and at least one inner nozzle tube having a first end and a second end. One of the nozzle body or nozzle tube includes a fuel plenum and a fuel passage extending therefrom, while the other of the nozzle body or nozzle tube includes a fuel injection hole slidably aligned with the fuel passage to form a fuel flow path therebetween at an interface between the body and the tube. The nozzle body and the nozzle tube are fixed against relative movement at the first ends of the nozzle body and nozzle tube, enabling the fuel flow path to close at the interface due to thermal growth after a flame enters the nozzle tube.

  1. Geologic nozzles

    USGS Publications Warehouse

    Werner, Kieffer S.

    1989-01-01

    The importance of the low characteristic velocities of geologic fluids has not been widely recognized, and as a result, the importance of supercritical and supersonic flow in geological processes has generally been underestimated. The lateral blast at Mount St. Helens, Washington, propelled a gas heavily laden with dust into the atmosphere. Because of the low sound speed in this gas (about 100 m/s), the flow was internally supersonic. Old Faithful Geyser, Wyoming, is a converging-diverging nozzle in which liquid water refilling the conduit during the recharge cycle changes during eruption into a two-phase liquid-vapor mixture with a very low sound velocity. The high sound speed of liquid water determines the characteristics of harmonic tremor observed at the geyser during the recharge interval, whereas the low sound speed of the liquid-vapor mixture influences the fluid flow characteristics of the eruption. At the rapids of the Colorado River in the Grand Canyon, Arizona, the channel is constricted into the shape of a converging-diverging nozzle by the debris flows that enter from tributary canyons. Both subcritical and supercritical flow occur within the rapids. -from Author

  2. Gas only nozzle

    DOEpatents

    Bechtel, William Theodore; Fitts, David Orus; DeLeonardo, Guy Wayne

    2002-01-01

    A diffusion flame nozzle gas tip is provided to convert a dual fuel nozzle to a gas only nozzle. The nozzle tip diverts compressor discharge air from the passage feeding the diffusion nozzle air swirl vanes to a region vacated by removal of the dual fuel components, so that the diverted compressor discharge air can flow to and through effusion holes in the end cap plate of the nozzle tip. In a preferred embodiment, the nozzle gas tip defines a cavity for receiving the compressor discharge air from a peripheral passage of the nozzle for flow through the effusion openings defined in the end cap plate.

  3. Scale model test results of several STOVL ventral nozzle concepts

    NASA Technical Reports Server (NTRS)

    Meyer, B. E.; Re, R. J.; Yetter, J. A.

    1991-01-01

    Short take-off and vertical landing (STOVL) ventral nozzle concepts are investigated by means of a static cold flow scale model at a NASA facility. The internal aerodynamic performance characteristics of the cruise, transition, and vertical lift modes are considered for four ventral nozzle types. The nozzle configurations examined include those with: butterfly-type inner doors and vectoring exit vanes; circumferential inner doors and thrust vectoring vanes; a three-port segmented version with circumferential inner doors; and a two-port segmented version with cylindrical nozzle exit shells. During the testing, internal and external pressure is measured, and the thrust and flow coefficients and resultant vector angles are obtained. The inner door used for ventral nozzle flow control is found to affect performance negatively during the initial phase of transition. The best thrust performance is demonstrated by the two-port segmented ventral nozzle due to the elimination of the inner door.

  4. Cold Flow Determination of the Internal Flow Environment Around the Submerged TVC Nozzle for the Space Shuttle SRM

    NASA Technical Reports Server (NTRS)

    Whitesides, R. H.; Ghosh, A.; Jenkins, S. L.; Bacchus, D. L.

    1989-01-01

    A series of subscale cold flow tests was performed to quantify the gas flow characteristics at the aft end of the Space Shuttle Solid Rocket Motor. This information was used to support the analyses of the redesigned nozzle/case joint. A portion of the thermal loads at the joint are due to the circumferential velocities and pressure gradients caused primarily by the gimbaling of the submerged nose TVC nozzle. When the nozzle centerline is vectored with respect to the motor centerline, asymmetries are set up in the flow field under the submerged nozzle and immediately adjacent to the nozzle/case joint. Specific program objectives included: determination of the effects of nozzle gimbal angle and propellant geometry on the circumferential flow field; measurement of the static pressure and gas velocities in the vicinity of the nozzle/case joint; use of scaling laws to apply the subscale cold flow data to the full scale SRM; and generation of data for use in validation of 3-D computational fluid dynamic, CFD, models of the SRM flow field. These tests were conducted in the NASA Marshall Space Flight Center Airflow Facility with a 7.5 percent scale model of the aft segment of the SRM. Static and dynamic pressures were measured in the model to quantify the flow field. Oil flow data was also acquired to obtain qualitative visual descriptions of the flow field. Nozzle gimbal angles of 0, 3.5, and 7 deg were used with propellant grain configurations corresponding to motor burn times of 0, 9, 19, and 114 seconds. This experimental program was successful in generating velocity and pressure gradient data for the flow field around the submerged nose nozzle of the Space Shuttle SRM at various burn times and gimbal angles. The nature of the flow field adjacent to the nozzle/case joint was determined with oil droplet streaks, and the velocity and pressure gradients were quantified with pitot probes and wall static pressure measurements. The data was applied to the full scale SRM thru

  5. Nozzle airfoil having movable nozzle ribs

    DOEpatents

    Yu, Yufeng Phillip; Itzel, Gary Michael

    2002-01-01

    A nozzle vane or airfoil structure is provided in which the nozzle ribs are connected to the side walls of the vane or airfoil in such a way that the ribs provide the requisite mechanical support between the concave side and convex side of the airfoil but are not locked in the radial direction of the assembly, longitudinally of the airfoil. The ribs may be bi-cast onto a preformed airfoil side wall structure or fastened to the airfoil by an interlocking slide connection and/or welding. By attaching the nozzle ribs to the nozzle airfoil metal in such a way that allows play longitudinally of the airfoil, the temperature difference induced radial thermal stresses at the nozzle airfoil/rib joint area are reduced while maintaining proper mechanical support of the nozzle side walls.

  6. Turbine combustor with fuel nozzles having inner and outer fuel circuits

    DOEpatents

    Uhm, Jong Ho; Johnson, Thomas Edward; Kim, Kwanwoo

    2013-12-24

    A combustor cap assembly for a turbine engine includes a combustor cap and a plurality of fuel nozzles mounted on the combustor cap. One or more of the fuel nozzles would include two separate fuel circuits which are individually controllable. The combustor cap assembly would be controlled so that individual fuel circuits of the fuel nozzles are operated or deliberately shut off to provide for physical separation between the flow of fuel delivered by adjacent fuel nozzles and/or so that adjacent fuel nozzles operate at different pressure differentials. Operating a combustor cap assembly in this fashion helps to reduce or eliminate the generation of undesirable and potentially harmful noise.

  7. Development of Land Segmentation, Stream-Reach Network, and Watersheds in Support of Hydrological Simulation Program-Fortran (HSPF) Modeling, Chesapeake Bay Watershed, and Adjacent Parts of Maryland, Delaware, and Virginia

    USGS Publications Warehouse

    Martucci, Sarah K.; Krstolic, Jennifer L.; Raffensperger, Jeff P.; Hopkins, Katherine J.

    2006-01-01

    The U.S. Geological Survey, U.S. Environmental Protection Agency Chesapeake Bay Program Office, Interstate Commission on the Potomac River Basin, Maryland Department of the Environment, Virginia Department of Conservation and Recreation, Virginia Department of Environmental Quality, and the University of Maryland Center for Environmental Science are collaborating on the Chesapeake Bay Regional Watershed Model, using Hydrological Simulation Program - FORTRAN to simulate streamflow and concentrations and loads of nutrients and sediment to Chesapeake Bay. The model will be used to provide information for resource managers. In order to establish a framework for model simulation, digital spatial datasets were created defining the discretization of the model region (including the Chesapeake Bay watershed, as well as the adjacent parts of Maryland, Delaware, and Virginia outside the watershed) into land segments, a stream-reach network, and associated watersheds. Land segmentation was based on county boundaries represented by a 1:100,000-scale digital dataset. Fifty of the 254 counties and incorporated cities in the model region were divided on the basis of physiography and topography, producing a total of 309 land segments. The stream-reach network for the Chesapeake Bay watershed part of the model region was based on the U.S. Geological Survey Chesapeake Bay SPARROW (SPAtially Referenced Regressions On Watershed attributes) model stream-reach network. Because that network was created only for the Chesapeake Bay watershed, the rest of the model region uses a 1:500,000-scale stream-reach network. Streams with mean annual streamflow of less than 100 cubic feet per second were excluded based on attributes from the dataset. Additional changes were made to enhance the data and to allow for inclusion of stream reaches with monitoring data that were not part of the original network. Thirty-meter-resolution Digital Elevation Model data were used to delineate watersheds for each

  8. Full-scale Investigation of Several Jet-engine Noise-reduction Nozzles

    NASA Technical Reports Server (NTRS)

    Coles, Willard D; Callaghan, Edmund E

    1957-01-01

    A number of nozzles which use the mixing interference of adjacent jets for noise suppression were investigated. Reductions in sound power of nearly 70 percent (5 db) with thrust losses of 1 percent were achieved. A method of calculating the limiting frequency affected by this type of suppression nozzle, that is , multiple-slot nozzles, is presented. Data are shown which indicate that further large reductions in sound power are not likely with mixing-interference nozzles.

  9. Cold spray nozzle design

    DOEpatents

    Haynes, Jeffrey D.; Sanders, Stuart A.

    2009-06-09

    A nozzle for use in a cold spray technique is described. The nozzle has a passageway for spraying a powder material, the passageway having a converging section and a diverging section, and at least the diverging section being formed from polybenzimidazole. In one embodiment of the nozzle, the converging section is also formed from polybenzimidazole.

  10. Spiral cooled fuel nozzle

    DOEpatents

    Fox, Timothy; Schilp, Reinhard

    2012-09-25

    A fuel nozzle for delivery of fuel to a gas turbine engine. The fuel nozzle includes an outer nozzle wall and a center body located centrally within the nozzle wall. A gap is defined between an inner wall surface of the nozzle wall and an outer body surface of the center body for providing fuel flow in a longitudinal direction from an inlet end to an outlet end of the fuel nozzle. A turbulating feature is defined on at least one of the central body and the inner wall for causing at least a portion of the fuel flow in the gap to flow transverse to the longitudinal direction. The gap is effective to provide a substantially uniform temperature distribution along the nozzle wall in the circumferential direction.

  11. Variable area nozzle including a plurality of convexly vanes with a crowned contour, in a vane to vane sealing arrangement and with nonuniform lengths

    NASA Technical Reports Server (NTRS)

    Arnold, Steven M. (Inventor); Penney, Nicholas (Inventor)

    2008-01-01

    A variable area nozzle comprising a concentric support and a plurality of convexly contoured self sealing vanes is disclosed and claimed. The vanes are circumferentially and rotatably mounted to the concentric support forming a nozzle infinitely positionable between a first position corresponding to a minimum area nozzle and a second position corresponding to a maximum area nozzle. A closer, which is preferably a shape memory alloy (SMA), urges the nozzle toward the first position corresponding to a minimum area nozzle. Periodically spaced openers act between adjacent vanes to urge the nozzle to a second position corresponding to a maximum area nozzle.

  12. Liquid rocket engine nozzles

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The nozzle is a major component of a rocket engine, having a significant influence on the overall engine performance and representing a large fraction of the engine structure. The design of the nozzle consists of solving simultaneously two different problems: the definition of the shape of the wall that forms the expansion surface, and the delineation of the nozzle structure and hydraulic system. This monography addresses both of these problems. The shape of the wall is considered from immediately upstream of the throat to the nozzle exit for both bell and annular (or plug) nozzles. Important aspects of the methods used to generate nozzle wall shapes are covered for maximum-performance shapes and for nozzle contours based on criteria other than performance. The discussion of structure and hydraulics covers problem areas of regeneratively cooled tube-wall nozzles and extensions; it treats also nozzle extensions cooled by turbine exhaust gas, ablation-cooled extensions, and radiation-cooled extensions. The techniques that best enable the designer to develop the nozzle structure with as little difficulty as possible and at the lowest cost consistent with minimum weight and specified performance are described.

  13. High speed nozzles task

    NASA Technical Reports Server (NTRS)

    Hamed, Awatef

    1995-01-01

    Supersonic cruise exhaust nozzles for advanced applications are optimized for a high nozzle pressure ratio (NPR) at design supersonic cruise Mach number and altitude. The performance of these nozzles with large expansion ratios are severely degraded for operations at subsonic speeds near sea level for NPR significantly less than the design values. The prediction of over-expanded 2DCD nozzles performance is critical to evaluating the internal losses and to the optimization of the integrated vehicle and propulsion system performance. The reported research work was aimed at validating and assessing existing computational methods and turbulence models for predicting the flow characteristics and nozzle performance at over-expanded conditions. Flow simulations in 2DCD nozzles were performed using five different turbulence models. The results are compared with the experimental data for the wall pressure distribution and thrust and flow coefficients at over-expanded static conditions.

  14. Turbine nozzle positioning system

    DOEpatents

    Norton, Paul F.; Shaffer, James E.

    1996-01-30

    A nozzle guide vane assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and being attached to conventional metallic components. The nozzle guide vane assembly includes an outer shroud having a mounting leg with an opening defined therein, a tip shoe ring having a mounting member with an opening defined therein, a nozzle support ring having a plurality of holes therein and a pin positioned in the corresponding opening in the outer shroud, opening in the tip shoe ring and the hole in the nozzle support ring. A rolling joint is provided between metallic components of the gas turbine engine and the nozzle guide vane assembly. The nozzle guide vane assembly is positioned radially about a central axis of the gas turbine engine and axially aligned with a combustor of the gas turbine engine.

  15. Turbine nozzle positioning system

    DOEpatents

    Norton, P.F.; Shaffer, J.E.

    1996-01-30

    A nozzle guide vane assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and being attached to conventional metallic components. The nozzle guide vane assembly includes an outer shroud having a mounting leg with an opening defined therein, a tip shoe ring having a mounting member with an opening defined therein, a nozzle support ring having a plurality of holes therein and a pin positioned in the corresponding opening in the outer shroud, opening in the tip shoe ring and the hole in the nozzle support ring. A rolling joint is provided between metallic components of the gas turbine engine and the nozzle guide vane assembly. The nozzle guide vane assembly is positioned radially about a central axis of the gas turbine engine and axially aligned with a combustor of the gas turbine engine. 9 figs.

  16. Experimental investigation on noise of cavitation nozzle and its chaotic behaviour

    NASA Astrophysics Data System (ADS)

    Zhang, Fenghua; Liu, Haifeng; Xu, Junchao; Tang, Chuanlin

    2013-07-01

    The researches of cavitation noise mainly focus on the incipiency and developing of cavitation to prevent the cavititation erosion in the hydraulic machinery, while there is few report about the collapse strength of cavitation bubbles produced by water jet through the cavitation nozzle to utilize efficiently the collapse energy of cavitation bubbles. The cavitation noise signals are collected with hydrophones for the cavitation nozzle and general nozzle at the target position and the nozzle exit separately in the conditions of different standoff distance. The features of signal's frequency spectrum and power spectrum are analyzed for various nozzles by way of classical methods. Meanwhile, based on chaotic theory, phase space reconstruction is processed and the maximum Lyapunov index is calculated separately for each cavitation signal's time series. The results of chaotic analysis are compared with the one of conventional analysis. The analyzed data show that there are the marked differences at the spectrum between the cavitation nozzle and general nozzle at the target position while the standoff distance is 35 mm, which mainly displays at the high frequency segment (60-120 kHz). The maximum Lyapunov index calculated appear at standoff distance 35 mm, which is an optimum standoff distance for the most bubbles to collapse at the target. At the nozzle exit, the noise signal of cavitation nozzle is different from the general nozzle, which also displays at the high frequency segment. The results demonstrate that the water jet modulated by the cavitation nozzle can produce effectually cavitation, and at the target position the amplitude and energy of noise spectrum in high frequency segment for cavitation nozzle are higher than conventional nozzle and the Lyapunov index of cavitation nozzle is larger than conventional nozzle as the standoff distance is less than 55 mm. The proposed research reveals that the cavitation noise produced by collapse of cavitation bubbles

  17. Multi-tube fuel nozzle with mixing features

    DOEpatents

    Hughes, Michael John

    2014-04-22

    A system includes a multi-tube fuel nozzle having an inlet plate and a plurality of tubes adjacent the inlet plate. The inlet plate includes a plurality of apertures, and each aperture includes an inlet feature. Each tube of the plurality of tubes is coupled to an aperture of the plurality of apertures. The multi-tube fuel nozzle includes a differential configuration of inlet features among the plurality of tubes.

  18. Gas only nozzle fuel tip

    DOEpatents

    Bechtel, William Theodore; Fitts, David Orus; DeLeonardo, Guy Wayne

    2002-01-01

    A diffusion flame nozzle gas tip is provided to convert a dual fuel nozzle to a gas only nozzle. The nozzle tip diverts compressor discharge air from the passage feeding the diffusion nozzle air swirl vanes to a region vacated by removal of the dual fuel components, so that the diverted compressor discharge air can flow to and through effusion holes in the end cap plate of the nozzle tip. In a preferred embodiment, the nozzle gas tip defines a cavity for receiving the compressor discharge air from a peripheral passage of the nozzle for flow through the effusion openings defined in the end cap plate.

  19. Stress and Fracture Mechanics Analyses of Boiling Water Reactor and Pressurized Water Reactor Pressure Vessel Nozzles

    SciTech Connect

    Yin, Shengjun; Bass, Bennett Richard; Stevens, Gary; Kirk, Mark

    2011-01-01

    This paper describes stress analysis and fracture mechanics work performed to assess boiling water reactor (BWR) and pressurized water reactor (PWR) nozzles located in the reactor pressure vessel (RPV) adjacent to the core beltline region. Various RPV nozzle geometries were investigated: 1. BWR recirculation outlet nozzle; 2. BWR core spray nozzle3 3. PWR inlet nozzle; ; 4. PWR outlet nozzle; and 5. BWR partial penetration instrument nozzle. The above nozzle designs were selected based on their proximity to the core beltline region, i.e., those nozzle configurations that are located close enough to the core region such that they may receive sufficient fluence prior to end-of-license (EOL) to require evaluation as part of establishing the allowed limits on heatup, cooldown, and hydrotest (leak test) conditions. These nozzles analyzed represent one each of the nozzle types potentially requiring evaluation. The purpose of the analyses performed on these nozzle designs was as follows: To model and understand differences in pressure and thermal stress results using a two-dimensional (2-D) axi-symmetric finite element model (FEM) versus a three-dimensional (3-D) FEM for all nozzle types. In particular, the ovalization (stress concentration) effect of two intersecting cylinders, which is typical of RPV nozzle configurations, was investigated; To verify the accuracy of a selected linear elastic fracture mechanics (LEFM) hand solution for stress intensity factor for a postulated nozzle corner crack for both thermal and pressure loading for all nozzle types; To assess the significance of attached piping loads on the stresses in the nozzle corner region; and To assess the significance of applying pressure on the crack face with respect to the stress intensity factor for a postulated nozzle corner crack.

  20. RSRM nozzle fixed housing cooldown test

    NASA Technical Reports Server (NTRS)

    Bolieau, D. J.

    1989-01-01

    Flight 5 aft segments with nozzles were exposed to -17 F temperatures while awaiting shipment to KSC in February, 1989. No records were found which show that any previous nozzles were exposed to air temperatures as low as those seen by the Flight 5 nozzles. Thermal analysis shows that the temperature of the fixed housing, and forward and aft exit cone components dropped as low as -10 F. Structural analysis of the nozzles at these low temperatures show the forward and aft exit cone adhesive bonds to have a positive margin of safety, based on a 2.0 safety factor. These analyses show the normal and shear stresses in the fixed housing bond as low values. However, the hoop and meridinal stresses were predicted to be in the 4000 psi range; the failure stress allowable of EA913NA adhesive at -7 F. If the bonds did break in directions perpendicular to the surfaces, called bond crazing, no normal bond strength would be lost. Testing was conducted in two phases, showing that no degradation to the adhesive bonds occurred while the Flight 5 nozzles were subjected to subzero temperatures. The results of these tests are documented. Phase 1 testing cooled a full-scale RSRM insulated fixed housing to -13 F, with extensive bondline inspections. Phase 2 testing cooled the witness panel adhesive tensile buttions to -13 F, with failure strengths recorded before, during, and after the cooldown.

  1. Arcjet Nozzle Design Impacts

    NASA Technical Reports Server (NTRS)

    Curran, Francis M.; Sovie, Amy J.; Haag, Thomas W.

    1989-01-01

    The effect of nozzle configuration on the operating characteristics of a low power dc arcjet thruster was determined. A conical nozzle with a 30 deg converging angle, a 20 deg diverging angle, and an area ratio of 225 served as the baseline case. Variations on the geometry included bell-shaped contours both up and downstream, and a downstream trumpet-shaped contour. The nozzles were operated over a range of specific power near that anticipated for on-orbit operation. Mass flow rate, thrust, current, and voltage were monitored to provide accurate comparisons between nozzles. The upstream contour was found to have minimal effect on arcjet operation. It was determined that the contour of the divergent section of the nozzle, that serves as the anode, was very important in determining the location of arc attachment, and thus had a significant impact on arcjet performance. The conical nozzle was judged to have the optimal current/voltage characteristics and produced the best performance of the nozzles tested.

  2. Nozzle for a turbomachine

    DOEpatents

    Lacy, Benjamin Paul; Kraemer, Gilbert Otto; Yilmaz, Ertan; Melton, Patrick Benedict

    2012-10-30

    A turbomachine includes a compressor, a combustor operatively connected to the compressor, and an injection nozzle operatively connected to the combustor. The injection nozzle includes a main body having a first end section that extends to a second end section to define an inner flow path. The injection nozzle further includes an outlet arranged at the second end section of the main body, at least one passage that extends within the main body and is fluidly connected to the outlet, and at least one conduit extending between the inner flow path and the at least one passage.

  3. Controlled overspray spray nozzle

    NASA Technical Reports Server (NTRS)

    Prasthofer, W. P. (Inventor)

    1981-01-01

    A spray system for a multi-ingredient ablative material wherein a nozzle A is utilized for suppressing overspray is described. The nozzle includes a cyclindrical inlet which converges to a restricted throat. A curved juncture between the cylindrical inlet and the convergent portion affords unrestricted and uninterrupted flow of the ablative material. A divergent bell-shaped chamber and adjustable nozzle exit B is utilized which provides a highly effective spray pattern in suppressing overspray to an acceptable level and producing a homogeneous jet of material that adheres well to the substrate.

  4. SCOUT Nozzle Data Book

    NASA Technical Reports Server (NTRS)

    Shieds, S.

    1976-01-01

    Available analyses and material property information are summarized relevant to the design of four rocket motor nozzles currently incorporated in the four solid propellant rocket stages of the NASA SCOUT launch vehicle. The nozzles discussed include those for the following motors: (1) first stage - Algol IIIA; (2) second stage - Castor IIA; (3) third stage - Antares IIA; and (4) fourth stage - Altair IIIA. Separate sections for each nozzle provide complete data packages. Information on the Antares IIB motor which had limited usage as an alternate motor for the third stage is included.

  5. MEMS-Based Spinning Nozzle

    NASA Technical Reports Server (NTRS)

    Okojie, Robert S. (Inventor)

    2003-01-01

    A nozzle body and assembly for delivering atomized fuel to a combustion chamber. The nozzle body is rotatably mounted onto a substrate. One or more curvilinear fuel delivery channels are in flow communication with an internal fuel distribution cavity formed in the nozzle body. Passage of pressurized fuel through the nozzle body causes the nozzle body to rotate. Components of the nozzle assembly are formed of silicon carbide having surfaces etched by deep reactive ion etching utilizing MEMS (micro-electro-mechanical systems) technology. A fuel premix chamber is carried on the substrate in flow communication with a supply passage in the nozzle body.

  6. Reduced coking of fuel nozzles

    SciTech Connect

    Mancini, A.A.; Sager, J.W.; Kobish, T.R.

    1989-01-17

    This patent describes a fuel nozzle useful for a gas turbine engine and having a nozzle face, the combination of fuel supply means on the nozzle, the fuel supply means including an annular fuel discharge body converging in a downstream direction toward a longitudinal central axis of the nozzle and terminating in a downstream fuel discharge orifice substantially on the central axis for discharging fuel from the orifice for mixing with air downstream of the nozzle face, air supply means on the nozzle for discharging air from the nozzle face, and means on the nozzle around the fuel discharge body cooperating with the air supply means for controllably discharging sufficient air flow with locally reduced swirl strength over the fuel discharge body to establish a recirculation zone spaced away from the nozzle face downstream thereof a sufficient distance to substantially reduce coking on the nozzle face.

  7. Influence of mixer nozzle velocity decay characteristics on CTOL-OTW jet noise shielding. [considering shielding effects in nozzle installation over wing

    NASA Technical Reports Server (NTRS)

    Vonglahn, U.; Groesbeck, D. E.

    1974-01-01

    Jet noise shielding benefits for CTOL engine-over-the-wing configurations were obtained with model scale multitube and lobed mixer nozzles and various shielding surface geometries. Spectral data were obtained with jet velocities from 585 to 1110 ft/sec. Correlation equations for predicting jet noise shielding benefits with single conical nozzle installations were modified to correlate the mixer nozzle data. The modification included consideration of the number of nozzle elements and the peak axial velocity decay in the flow field adjacent to the shielding surface. The effect of forward velocity on jet noise attenuation by a shielding surface is discussed.

  8. Laser cutting nozzle

    DOEpatents

    Ramos, T.J.

    1982-09-30

    A laser cutting nozzle for use with a laser cutting apparatus directing a focused beam to a spot on a work piece. The nozzle has a cylindrical body with a conical tip which together have a conically shaped hollow interior with the apex at a small aperture through the tip. The conical hollow interior is shaped to match the profile of the laser beam, at full beamwidth, which passes through the nozzle to the work piece. A plurality of gas inlet holes extend through the body to the hollow interior and are oriented to produce a swirling flow of gas coaxially through the nozzle and out the aperture, aligned with the laser beam, to the work piece.

  9. Laser cutting nozzle

    DOEpatents

    Ramos, Terry J.

    1984-01-01

    A laser cutting nozzle for use with a laser cutting apparatus directing a focused beam to a spot on a work piece. The nozzle has a cylindrical body with a conical tip which together have a conically shaped hollow interior with the apex at a small aperture through the tip. The conical hollow interior is shaped to match the profile of the laser beam, at full beamwidth, which passes through the nozzle to the work piece. A plurality of gas inlet holes extend through the body to the hollow interior and are oriented to produce a swirling flow of gas coaxially through the nozzle and out the aperture, aligned with the laser beam, to the work piece. BACKGROUND OF THE INVENTION

  10. Metal atomization spray nozzle

    DOEpatents

    Huxford, Theodore J.

    1993-01-01

    A spray nozzle for a magnetohydrodynamic atomization apparatus has a feed passage for molten metal and a pair of spray electrodes mounted in the feed passage. The electrodes, diverging surfaces which define a nozzle throat and diverge at an acute angle from the throat. Current passes through molten metal when fed through the throat which creates the Lorentz force necessary to provide atomization of the molten metal.

  11. Inlet nozzle assembly

    DOEpatents

    Christiansen, David W.; Karnesky, Richard A.; Precechtel, Donald R.; Smith, Bob G.; Knight, Ronald C.

    1987-01-01

    An inlet nozzle assembly for directing coolant into the duct tube of a fuel assembly attached thereto. The nozzle assembly includes a shell for housing separable components including an orifice plate assembly, a neutron shield block, a neutron shield plug, and a diffuser block. The orifice plate assembly includes a plurality of stacked plates of differently configurated and sized openings for directing coolant therethrough in a predesigned flow pattern.

  12. Metal atomization spray nozzle

    DOEpatents

    Huxford, T.J.

    1993-11-16

    A spray nozzle for a magnetohydrodynamic atomization apparatus has a feed passage for molten metal and a pair of spray electrodes mounted in the feed passage. The electrodes, diverging surfaces which define a nozzle throat and diverge at an acute angle from the throat. Current passes through molten metal when fed through the throat which creates the Lorentz force necessary to provide atomization of the molten metal. 6 figures.

  13. Inlet nozzle assembly

    DOEpatents

    Christiansen, D.W.; Karnesky, R.A.; Knight, R.C.; Precechtel, D.R.; Smith, B.G.

    1985-09-09

    An inlet nozzle assembly for directing coolant into the duct tube of a fuel assembly attached thereto. The nozzle assembly includes a shell for housing separable components including an orifice plate assembly, a neutron shield block, a neutron shield plug, and a diffuser block. The orifice plate assembly includes a plurality of stacked plates of differently configurated and sized openings for directing coolant therethrough in a predesigned flow pattern.

  14. Transonic swirling nozzle flow

    NASA Technical Reports Server (NTRS)

    Keith, Theo G., Jr.; Pawlas, Gary E.

    1991-01-01

    A numerical model of viscous transonic swirling flow in axisymmetric nozzles is developed. MacCormack's implicit Gauss-Seidel method is applied to the thin-layer Navier-Stokes equations in transformed coordinates. Numerical results are compared with experimental data to validate the method. The effect of swirl and viscosity on nozzle performance are demonstrated by examining wall pressures, Mach contours, and integral parameters.

  15. ASRM nozzle thermal analysis

    NASA Technical Reports Server (NTRS)

    Strobel, Forrest; King, Belinda

    1993-01-01

    This report describes results from the nozzle thermal analysis contract which has been performed to support NASA/Marshall Space Flight Center in the development of the Advanced Solid Rocket Motor (ASRM). The emphasis of this study has been directed to four potential problem areas of the nozzle. These areas are the submerged nozzle region containing the flex seal, the nozzle entrance region, the material interface region in the nozzle exit cone, and the aft region of the exit cone. This study was limited throughout by inadequate material response models, especially for the polyisoprene flex seal and the low density carbon phenolic used in the exit cone. Thermal response and particle erosion calculations were performed for each of the potential problem areas. Results from these studies showed excessive erosion (large negative safety margins) to occur in the flex seal and nozzle entrance regions. The exit cone was found to be marginally adequate (near zero safety margins) and the material interface region was found not to be a problem.

  16. ASRM nozzle thermal analysis

    NASA Astrophysics Data System (ADS)

    Strobel, Forrest; King, Belinda

    1993-11-01

    This report describes results from the nozzle thermal analysis contract which has been performed to support NASA/Marshall Space Flight Center in the development of the Advanced Solid Rocket Motor (ASRM). The emphasis of this study has been directed to four potential problem areas of the nozzle. These areas are the submerged nozzle region containing the flex seal, the nozzle entrance region, the material interface region in the nozzle exit cone, and the aft region of the exit cone. This study was limited throughout by inadequate material response models, especially for the polyisoprene flex seal and the low density carbon phenolic used in the exit cone. Thermal response and particle erosion calculations were performed for each of the potential problem areas. Results from these studies showed excessive erosion (large negative safety margins) to occur in the flex seal and nozzle entrance regions. The exit cone was found to be marginally adequate (near zero safety margins) and the material interface region was found not to be a problem.

  17. Full-Scale Investigation of Several Jet-Engine Noise-Reduction Nozzles

    NASA Technical Reports Server (NTRS)

    Coles, Willard D; Callaghan, Edmund E

    1958-01-01

    A number of noise-suppression nozzles were tested on full-scale engines. In general, these nozzles achieved noise reduction by the mixing interference of adjacent jets, that is, by using multiple-slot-nozzles. Several of the nozzles achieved reductions in sound power of approximately 5 decibels (nearly 70 percent) with small thrust losses (approx. 1 percent). The maximum sound-pressure level was reduced by as much as 18 decibels in particular frequency bands. Some of the nozzles showed considerable spatial asymmetry; that is, the sound field was not rotationally symmetrical. A method of calculating the limiting frequency effected by such nozzles is presented. Furthermore data are shown that appear to indicate that further reductions in sound power will not be easily achieved from nozzles using mixing interference as a means of noise suppression

  18. Altitude Compensating Nozzle Cold Flow Test Results

    NASA Technical Reports Server (NTRS)

    Ruf, J. H.; McDaniels, D. M.

    2002-01-01

    A suite of four altitude compensating nozzle (ACN) concepts were evaluated by NASA MSFC in the Nozzle Test Facility. The ACN concepts were a dual bell, a dual expander, an annular plug nozzle and an expansion deflection nozzle. Two reference bell nozzles were also tested. Axial thrust and nozzle wall static pressures were measured for each nozzle over a wide range of nozzle pressure ratios. The nozzle hardware and test program are described. Sample test results are presented.

  19. High performance Solid Rocket Motor (SRM) submerged nozzle/combustion cavity flowfield assessment

    NASA Technical Reports Server (NTRS)

    Freeman, J. A.; Chan, J. S.; Murph, J. E.; Xiques, K. E.

    1987-01-01

    Two and three dimensional internal flowfield solutions for critical points in the Space Shuttle solid rocket booster burn time were developed using the Lockheed Huntsville GIM/PAID Navier-Stokes solvers. These perfect gas, viscous solutions for the high performance motor characterize the flow in the aft segment and nozzle of the booster. Two dimensional axisymmetric solutions were developed at t = 20 and t = 85 sec motor burn times. The t = 85 sec solution indicates that the aft segment forward inhibitor stub produces vortices with are shed and convected downwards. A three dimensional 3.5 deg gimbaled nozzle flowfield solution was developed for the aft segment and nozzle at t = 9 sec motor burn time. This perfect gas, viscous analysis, provided a steady state solution for the core region and the flow through the nozzle, but indicated that unsteady flow exists in the region under the nozzle nose and near the flexible boot and nozzle/case joint. The flow in the nozzle/case joint region is characterized by low magnitude pressure waves which travel in the circumferential direction. From the two and three dimensional flowfield calculations presented it can be concluded that there is no evidence from these results that steady state gas dynamics is the primary mechanism resulting in the nozzle pocketing erosion experienced on SRM nozzles 8A or 17B. The steady state flowfield results indicate pocketing erosion is not directly initiated by a steady state gas dynamics phenomenon.

  20. Nozzle mixing apparatus

    SciTech Connect

    Mensink, D.L.

    1992-12-31

    This invention is comprised of a nozzle device for causing two fluids to mix together. In particular, a spray nozzle comprise two hollow, concentric housings, an inner housing and an outer housing. The inner housing has a channel formed therethrough for a first fluid. Its outer surface cooperates with the interior surface of the outer housing to define the second channel for a second fluid. The outer surface of the inner housing and the inner surface of the outer housing each carry a plurality of vanes that interleave but do not touch, each vane of one housing being between two vanes of the other housing. The vanes are curved and the inner surface of the outer housing and the outer surface of the inner housing converge to narrow the second channel. The shape of second channel results in a swirling, accelerating second fluid that will impact the first fluid just past the end of the nozzle where mixing will take place.

  1. Turbine nozzle attachment system

    DOEpatents

    Norton, Paul F.; Shaffer, James E.

    1995-01-01

    A nozzle guide vane assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and being attached to conventional metallic components. The nozzle guide vane assembly includes a pair of legs extending radially outwardly from an outer shroud and a pair of mounting legs extending radially inwardly from an inner shroud. Each of the pair of legs and mounting legs have a pair of holes therein. A plurality of members attached to the gas turbine engine have a plurality of bores therein which axially align with corresponding ones of the pair of holes in the legs. A plurality of pins are positioned within the corresponding holes and bores radially positioning the nozzle guide vane assembly about a central axis of the gas turbine engine.

  2. Turbine nozzle attachment system

    DOEpatents

    Norton, P.F.; Shaffer, J.E.

    1995-10-24

    A nozzle guide vane assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and is attached to conventional metallic components. The nozzle guide vane assembly includes a pair of legs extending radially outwardly from an outer shroud and a pair of mounting legs extending radially inwardly from an inner shroud. Each of the pair of legs and mounting legs have a pair of holes therein. A plurality of members attached to the gas turbine engine have a plurality of bores therein which axially align with corresponding ones of the pair of holes in the legs. A plurality of pins are positioned within the corresponding holes and bores radially positioning the nozzle guide vane assembly about a central axis of the gas turbine engine. 3 figs.

  3. Oil burner nozzle

    DOEpatents

    Wright, Donald G.

    1982-01-01

    An oil burner nozzle for use with liquid fuels and solid-containing liquid fuels. The nozzle comprises a fuel-carrying pipe, a barrel concentrically disposed about the pipe, and an outer sleeve retaining member for the barrel. An atomizing vapor passes along an axial passageway in the barrel, through a bore in the barrel and then along the outer surface of the front portion of the barrel. The atomizing vapor is directed by the outer sleeve across the path of the fuel as it emerges from the barrel. The fuel is atomized and may then be ignited.

  4. Duplex tab exhaust nozzle

    NASA Technical Reports Server (NTRS)

    Gutmark, Ephraim Jeff (Inventor); Martens, Steven (nmn) (Inventor)

    2012-01-01

    An exhaust nozzle includes a conical duct terminating in an annular outlet. A row of vortex generating duplex tabs are mounted in the outlet. The tabs have compound radial and circumferential aft inclination inside the outlet for generating streamwise vortices for attenuating exhaust noise while reducing performance loss.

  5. Nozzles of insecticide sprayers

    PubMed Central

    Knipe, Fred W.

    1955-01-01

    Certain performance characteristics of the insecticide-sprayer nozzle tip and its relationship to the pressure regulator are discussed. After analysing the effectiveness of residual spraying at various pressures, the author concludes that low-pressure application would best attain the pattern and rate of insecticide discharge laid down by the WHO Expert Committee on Insecticides. PMID:14364190

  6. Welding nozzle position manipulator

    NASA Technical Reports Server (NTRS)

    Gilbert, Jeffrey L. (Inventor); Gutow, David A. (Inventor)

    1994-01-01

    The present invention is directed to a welding nozzle position manipulator. The manipulator consists of an angle support to which the remaining components of the device are attached either directly or indirectly. A pair of pivotal connections attach a weld nozzle holding link to the angle support and provide a two axis freedom of movement of the holding link with respect to the support angle. The manipulator is actuated by a pair of adjusting screws angularly mounted to the angle support. These screws contact a pair of tapered friction surfaces formed on the upper portion of the welding nozzle holding link. A spring positioned between the upper portions of the support angle and the holding link provides a constant bias engagement between the friction surfaces of the holding link and the adjustment screws, so as to firmly hold the link in position and to eliminate any free play in the adjustment mechanism. The angular relationships between the adjustment screws, the angle support and the tapered friction surfaces of the weld nozzle holding link provide a geometric arrangement which permits precision adjustment of the holding link with respect to the angle support and also provides a solid holding link mount which is resistant to movement from outside forces.

  7. Leaf seal for gas turbine stator shrouds and a nozzle band

    DOEpatents

    Burdgick, Steven Sebastian; Sexton, Brendan Francis

    2002-01-01

    A leaf seal assembly is secured to the trailing edge of a shroud segment for sealing between the shroud segment and the leading edge side wall of a nozzle outer band. The leaf seal includes a circumferentially elongated seal plate biased by a pair of spring clips disposed in a groove along the trailing edge of the shroud segment to maintain the seal plate in engagement with the flange on the leading edge side wall of the nozzle outer band. The leaf seal plate and spring clips receive pins tack-welded to the shroud segment to secure the leaf seal assembly in place.

  8. Forced Mixer Nozzle Optimization

    NASA Technical Reports Server (NTRS)

    Sheoran, Yogi; Hoover, Robert; Schuster, William; Anderson, Morris; Weir, Donald S.

    1999-01-01

    Computational fluid dynamic (CFD) and computational acoustic analyses (CAA) were performed for a TFE731-40 compound nozzle, a TFE731-60 mixer nozzle and an Energy Efficient Engine (E(sup 3)) mixer nozzle for comparison with available data. The CFD analyses were performed with a three dimensional, Navier-Stokes solution of the flowfield on an unstructured grid using the RAMPANT program. The CAA analyses were performed with the NASA Glenn MGB program using a structured grid. A successful aerodynamic solution for the TFE731-40 compound nozzle operating statically was obtained, simulating an engine operating on a test stand. Analysis of the CFD results of the TFE731-40 with the MGB program produced predicted sound power levels that agree quite well with the measured data front full-scale static engine tests. Comparison of the predicted sound pressure with the data show good agreement near the jet axis, but the noise levels are overpredicted at angles closer to the inlet. The predicted sound power level for the TFE731-60 did not agree as well with measured static engine data as the TFE731-40. Although a reduction in the predicted noise level due to the mixed flow was observed, the reduction was not as significant as the measured data. The analysis of the V2 mixer from the E(sup 3) study showed that peak temperatures predicted in the mixer exit flowfield were within 5 percent of the values measured by the exit probes. The noise predictions of the V2 mixer nozzle tended to be 3-5 dB higher in peak noise level than the measurements. In addition, the maximum frequency of the noise was also overpredicted. An analysis of the 3 candidate mixer nozzle configurations demonstrated the feasibility of using centerbody lobes and porosity to improve mixing efficiency. A final configuration was designed with a predicted thermal mixing efficiency that was 5 percent higher than the 3 candidate mixers. The results of the MGB noise calculations show that the final design will exceed the

  9. Premixed direct injection nozzle

    DOEpatents

    Zuo, Baifang; Johnson, Thomas Edward; Lacy, Benjamin Paul; Ziminsky, Willy Steve

    2011-02-15

    An injection nozzle having a main body portion with an outer peripheral wall is disclosed. The nozzle includes a plurality of fuel/air mixing tubes disposed within the main body portion and a fuel flow passage fluidly connected to the plurality of fuel/air mixing tubes. Fuel and air are partially premixed inside the plurality of the tubes. A second body portion, having an outer peripheral wall extending between a first end and an opposite second end, is connected to the main body portion. The partially premixed fuel and air mixture from the first body portion gets further mixed inside the second body portion. The second body portion converges from the first end toward said second end. The second body portion also includes cooling passages that extend along all the walls around the second body to provide thermal damage resistance for occasional flame flash back into the second body.

  10. The whistler nozzle phenomenon

    NASA Technical Reports Server (NTRS)

    Hussain, A. K. M. F.; Hasan, M. A. Z.

    1982-01-01

    The whistler nozzle is a simple device which can induce jet self-excitations of controllable amplitudes and frequencies and appears highly promising for many applications involving turbulent transport, combustion and aerodynamic noise. The characteristics of this curious phenomenon are documented for different values of the controlling parameters and attempts to explain the phenomenon. It is shown that the whistler excitation results from the coupling of two independent resonance mechanisms: shear-layer tone resulting from the impingement of the pipe-exit shear layer on the collar lip, and organ-pipe resonance of the pipe-nozzle. The crucial role of the shear-layer tone in driving the organ-pipe resonance is proven by reproducing the event in pipe-ring and pipe-hole configurations in the absence of the collar. It is also shown that this phenomenon is the strongest when the self-excitation frequency matches the preferred mode of the jet.

  11. Atomizing nozzle and method

    SciTech Connect

    Ting, Jason; Anderson, Iver E.; Terpstra, Robert L.

    2000-03-16

    A high pressure close-coupled gas atomizing nozzle includes multiple discrete gas jet discharge orifices having aerodynamically designed convergent-divergent geometry with an first converging section communicated to a gas supply manifold and to a diverging section by a constricted throat section to increase atomizing gas velocity. The gas jet orifices are oriented at gas jet apex angle selected relative to the melt supply tip apex angle to establish a melt aspiration condition at the melt supply tip.

  12. Numerical Simulations of Canted Nozzle and Scarfed Nozzle Flow Fields

    NASA Astrophysics Data System (ADS)

    Javed, Afroz; Chakraborty, Debasis

    2016-06-01

    Computational fluid dynamics (CFD) techniques are used for the analysis of issues concerning non-conventional (canted and scarfed) nozzle flow fields. Numerical simulations are carried out for the quality of flow in terms of axisymmetric nature at the inlet of canted nozzles of a rocket motor. Two different nozzle geometries are examined. The analysis of these simulation results shows that the flow field at the entry of the nozzles is non axisymmetric at the start of the motor. With time this asymmetry diminishes, also the flow becomes symmetric before the nozzle throat, indicating no misalignment of thrust vector with the nozzle axis. The qualitative flow fields at the inlet of the nozzles are used in selecting the geometry with lesser flow asymmetry. Further CFD methodology is used to analyse flow field of a scarfed nozzle for the evaluation of thrust developed and its direction. This work demonstrates the capability of the CFD based methods for the nozzle analysis problems which were earlier solved only approximately by making simplifying assumptions and semi empirical methods.

  13. Fundamental Study of Extendible Nozzle and Dual-Bell Nozzle for Reusable Rocket Engine

    NASA Astrophysics Data System (ADS)

    Hasegawa, Keiichi; Kumakawa, Akinaga; Kusaka, Kazuo; Sato, Masahiro; Tadano, Makoto; Konno, Akira; Aoki, Hiroshi; Namura, Eijiro; Atsumi, Masahiro

    An extendible nozzle and a dual-bell nozzle are considered to be feasible devices to improve performance of booster engines for near future reusable launch vehicles. Hot firing tests were conducted at a high altitude test stand, using four kinds of nozzles as follows: a standard bell nozzle, a fixed step nozzle simulating the transient nozzle position during nozzle extension, a dual-bell nozzle and a movable extendible nozzle. Measured nozzle performance, pressure distribution and heat transfer characteristics were compared with those of CFD analysis. The dual-bell nozzle performance was shown to be lower than those of the standard bell nozzle and the step nozzle. Reverse flow of combustion gas through the gap between fixed nozzle and movable extendible nozzle was not observed during nozzle extension.

  14. Rocket nozzle thermal shock tests in an arc heater facility

    NASA Technical Reports Server (NTRS)

    Painter, James H.; Williamson, Ronald A.

    1986-01-01

    A rocket motor nozzle thermal structural test technique that utilizes arc heated nitrogen to simulate a motor burn was developed. The technique was used to test four heavily instrumented full-scale Star 48 rocket motor 2D carbon/carbon segments at conditions simulating the predicted thermal-structural environment. All four nozzles survived the tests without catastrophic or other structural failures. The test technique demonstrated promise as a low cost, controllable alternative to rocket motor firing. The technique includes the capability of rapid termination in the event of failure, allowing post-test analysis.

  15. Pre-stressed/pre-compressed gas turbine nozzle

    DOEpatents

    Jang, Hoyle; Itzel, Gary Michael; Yu, Yufeng Phillip

    2002-01-01

    A method of increasing low cycle fatigue life of a turbine nozzle comprising a plurality of stationary airfoils extending between radially inner and outer ring segments comprising a) providing at least one radial passage in each of the plurality of airfoils; b) installing a rod in the radial passage extending between the radially inner and outer ring segments and fixing one end of the rod to one of the inner and outer rings; and c) pre-loading the rod to compress the airfoil between the inner and outer ring segments.

  16. Shuttle subscale ablative nozzle tests

    NASA Technical Reports Server (NTRS)

    Powers, L. B.; Bailey, R. L.

    1980-01-01

    Recent subscale nozzle tests have identified new and promising carbon phenolic nozzle ablatives which utilize staple rayon, PAN, and pitch based carbon cloth. A 4-inch throat diameter submerged test nozzle designed for the 48-inch Jet Propulsion Laboratory char motor was used to evaluate five different designs incorporating 20 candidate ablatives. Test results indicate that several pitch and PAN-based carbon phenolic ablatives can provide erosion and char performance equivalent or superior to the present continuous rayon-based SRM ablative.

  17. Jet vectoring through nozzle asymmetry

    NASA Astrophysics Data System (ADS)

    Roh, Chris; Rosakis, Alexandros; Gharib, Morteza

    2015-11-01

    Previously, we explored the functionality of a tri-leaflet anal valve of a dragonfly larva. We saw that the dragonfly larva is capable of controlling the three leaflets independently to asymmetrically open the nozzle. Such control resulted in vectoring of the jet in various directions. To further understand the effect of asymmetric nozzle orifice, we tested jet flow through circular asymmetric nozzles. We report the relationship between nozzle asymmetry and redirecting of the jet at various Reynolds numbers. This material is based upon work supported by the National Science Foundation under Grant No. CBET-1511414; additional support by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469.

  18. Development of Relations of Stream Stage to Channel Geometry and Discharge for Stream Segments Simulated with Hydrologic Simulation Program-Fortran (HSPF), Chesapeake Bay Watershed and Adjacent Parts of Virginia, Maryland, and Delaware

    USGS Publications Warehouse

    Moyer, Douglas; Bennett, Mark

    2007-01-01

    The U.S. Geological Survey (USGS), U.S. Environmental Protection Agency (USEPA), Chesapeake Bay Program (CBP), Interstate Commission for the Potomac River Basin (ICPRB), Maryland Department of the Environment (MDE), Virginia Department of Conservation and Recreation (VADCR), and University of Maryland (UMD) are collaborating to improve the resolution of the Chesapeake Bay Regional Watershed Model (CBRWM). This watershed model uses the Hydrologic Simulation Program-Fortran (HSPF) to simulate the fate and transport of nutrients and sediment throughout the Chesapeake Bay watershed and extended areas of Virginia, Maryland, and Delaware. Information from the CBRWM is used by the CBP and other watershed managers to assess the effectiveness of water-quality improvement efforts as well as guide future management activities. A critical step in the improvement of the CBRWM framework was the development of an HSPF function table (FTABLE) for each represented stream channel. The FTABLE is used to relate stage (water depth) in a particular stream channel to associated channel surface area, channel volume, and discharge (streamflow). The primary tool used to generate an FTABLE for each stream channel is the XSECT program, a computer program that requires nine input variables used to represent channel morphology. These input variables are reach length, upstream and downstream elevation, channel bottom width, channel bankfull width, channel bankfull stage, slope of the floodplain, and Manning's roughness coefficient for the channel and floodplain. For the purpose of this study, the nine input variables were grouped into three categories: channel geometry, Manning's roughness coefficient, and channel and floodplain slope. Values of channel geometry for every stream segment represented in CBRWM were obtained by first developing regional regression models that relate basin drainage area to observed values of bankfull width, bankfull depth, and bottom width at each of the 290 USGS

  19. Seal accommodating thermal expansion between adjacent casings in gas turbine engine

    NASA Technical Reports Server (NTRS)

    Marra, John J. (Inventor)

    1992-01-01

    A casing around a turbine and a casing around discharge nozzles have a concentrically arranged shell portion. The seal contains internal pressure while accommodating eccentric, expansion and axial travel. Arcuate seal segments have one leg sealing against a radial surface extending from the inner shell and the other leg against the outer shell. A linkage guides travel of the segments.

  20. Industrial jet noise: Coanda nozzles

    NASA Astrophysics Data System (ADS)

    Li, P.; Halliwell, N. A.

    1985-04-01

    Within the U.K. manufacturing industries noise from industrial jets ranks third as a major contributor to industrial deafness. Noise control is hindered because use is made of the air once it has exuded from the nozzle exit. Important tasks include swarf removal, paint spreading, cooling, etc. Nozzles which employ the Coanda effect appear to offer the possibility of significant noise reduction whilst maintaining high thrust efficiency when compared with the commonly used simple open pipe or ordinary convergent nozzle. In this paper the performance of Coanda-type nozzles is examined in detail and an index rating for nozzle performance is introduced. Results show that far field stagnation pressure distributions are Gaussian and similar in all cases with a dispersion coefficient σ = 0·64. Noise reduction and thrust efficiency are shown to be closely related to the design geometry of the central body of the nozzle. Performance is based on four fundamental characteristics, these being the noise level at 1 m from the exit and at a 90° station to the nozzle axis, and the thrust on a chosen profile, the noise reduction and the thrust efficiency. Physically, performance is attributed to flow near field effects where, although all nozzles are choked, shock cell associated noise is absent.

  1. Progress toward synergistic hypermixing nozzles

    NASA Technical Reports Server (NTRS)

    Davis, D. O.; Hingst, W. R.

    1991-01-01

    Mean flow measurements were obtained for air-to-air mixing downstream of swept and unswept ramp wall mounted hypermixing nozzle configurations. Aside from the sweep of the ramps, the two nozzle configurations studied are identical. The nozzles inject three parallel supersonic jets at a 15 deg angle (relative to the wind tunnel wall) into a supersonic freestream. Mach number and volume fraction distributions in a transverse plane 11.1 nozzle heights downstream from the nozzle exit plane were measured. Data are presented for a freestream Mach number of three at a matched static pressure condition and also at underexpanded static pressure condition (pressure ratio = 5). Surface oil flow visualization was used to study the near wall flow behavior. The results indicate that the swept ramp injectors produce stronger and larger vortex pairs than the unswept ramp injectors. The increased interaction between the swept ramp model's larger vortex pairs yields better mixing characteristics for this model.

  2. Electro-Optic Segment-Segment Sensors for Radio and Optical Telescopes

    NASA Technical Reports Server (NTRS)

    Abramovici, Alex

    2012-01-01

    A document discusses an electro-optic sensor that consists of a collimator, attached to one segment, and a quad diode, attached to an adjacent segment. Relative segment-segment motion causes the beam from the collimator to move across the quad diode, thus generating a measureable electric signal. This sensor type, which is relatively inexpensive, can be configured as an edge sensor, or as a remote segment-segment motion sensor.

  3. Arcjet Nozzle Area Ratio Effects

    NASA Technical Reports Server (NTRS)

    Curran, Francis M.; Sarmiento, Charles J.; Birkner, Bjorn W.; Kwasny, James

    1990-01-01

    An experimental investigation was conducted to determine the effect of nozzle area ratio on the operating characteristics and performance of a low power dc arcjet thruster. Conical thoriated tungsten nozzle inserts were tested in a modular laboratory arcjet thruster run on hydrogen/nitrogen mixtures simulating the decomposition products of hydrazine. The converging and diverging sides of the inserts had half angles of 30 and 20 degrees, respectively, similar to a flight type unit currently under development. The length of the diverging side was varied to change the area ratio. The nozzle inserts were run over a wide range of specific power. Current, voltage, mass flow rate, and thrust were monitored to provide accurate comparisons between tests. While small differences in performance were observed between the two nozzle inserts, it was determined that for each nozzle insert, arcjet performance improved with increasing nozzle area ratio to the highest area ratio tested and that the losses become very pronounced for area ratios below 50. These trends are somewhat different than those obtained in previous experimental and analytical studies of low Re number nozzles. It appears that arcjet performance can be enhanced via area ratio optimization.

  4. Arcjet nozzle area ratio effects

    NASA Technical Reports Server (NTRS)

    Curran, Francis M.; Sarmiento, Charles J.; Birkner, Bjorn W.; Kwasny, James

    1990-01-01

    An experimental investigation was conducted to determine the effect of nozzle area ratio on the operating characteristics and performance of a low power dc arcjet thruster. Conical thoriated tungsten nozzle inserts were tested in a modular laboratory arcjet thruster run on hydrogen/nitrogen mixtures simulating the decomposition products of hydrazine. The converging and diverging sides of the inserts had half angles of 30 and 20 degrees, respectively, similar to a flight type unit currently under development. The length of the diverging side was varied to change the area ratio. The nozzle inserts were run over a wide range of specific power. Current, voltage, mass flow rate, and thrust were monitored to provide accurate comparisons between tests. While small differences in performance were observed between the two nozzle inserts, it was determined that for each nozzle insert, arcjet performance improved with increasing nozzle area ratio to the highest area ratio tested and that the losses become very pronounced for area ratios below 50. These trends are somewhat different than those obtained in previous experimental and analytical studies of low Re number nozzles. It appears that arcjet performance can be enhanced via area ratio optimization.

  5. Segmented rail linear induction motor

    DOEpatents

    Cowan, Jr., Maynard; Marder, Barry M.

    1996-01-01

    A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces.

  6. Segmented rail linear induction motor

    DOEpatents

    Cowan, M. Jr.; Marder, B.M.

    1996-09-03

    A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces. 6 figs.

  7. Effects of nozzle-strut integrated design concepton on the subsonic turbine stage flowfield

    NASA Astrophysics Data System (ADS)

    Liu, Jun; Du, Qiang; Liu, Guang; Wang, Pei; Zhu, Junqiang

    2014-10-01

    In order to shorten aero-engine axial length, substituting the traditional long chord thick strut design accompanied with the traditional low pressure(LP) stage nozzle, LP turbine is integrated with intermediate turbine duct (ITD). In the current paper, five vanes of the first stage LP turbine nozzle is replaced with loaded struts for supporting the engine shaft, and providing oil pipes circumferentially which fulfilled the areo-engine structure requirement. However, their bulky geometric size represents a more effective obstacle to flow from high pressure (HP) turbine rotor. These five struts give obvious influence for not only the LP turbine nozzle but also the flowfield within the ITD, and hence cause higher loss. Numerical investigation has been undertaken to observe the influence of the Nozzle-Strut integrated design concept on the flowfield within the ITD and the nearby nozzle blades. According to the computational results, three main conclusions are finally obtained. Firstly, a noticeable low speed area is formed near the strut's leading edge, which is no doubt caused by the potential flow effects. Secondly, more severe radial migration of boundary layer flow adjacent to the strut's pressure side have been found near the nozzle's trailing edge. Such boundary layer migration is obvious, especially close to the shroud domain. Meanwhile, radial pressure gradient aggravates this phenomenon. Thirdly, velocity distribution along the strut's pressure side on nozzle's suction surface differs, which means loading variation of the nozzle. And it will no doubt cause nonuniform flowfield faced by the downstream rotor blade.

  8. Injection nozzle for a turbomachine

    DOEpatents

    Uhm, Jong Ho; Johnson, Thomas Edward; Kim, Kwanwoo

    2012-09-11

    A turbomachine includes a compressor, a combustor operatively connected to the compressor, an end cover mounted to the combustor, and an injection nozzle assembly operatively connected to the combustor. The injection nozzle assembly includes a first end portion that extends to a second end portion, and a plurality of tube elements provided at the second end portion. Each of the plurality of tube elements defining a fluid passage includes a body having a first end section that extends to a second end section. The second end section projects beyond the second end portion of the injection nozzle assembly.

  9. NERVA nozzle design status report

    NASA Technical Reports Server (NTRS)

    Williams, J. J.; Pickering, J. L.; Ackerman, R. G.

    1972-01-01

    The results of the design analyses are presented along with the status of the attained design maturity of the structural elements of the nozzle jacket and various aspects of the coolant passages. The design analyses relating to the nozzle shell were based on design allowables as supported by cursory values obtained from ARMCO 22-13-5 nozzle forgings. The major aspects of the coolant passages considered include: low cycle thermal fatigue, ability to operate at 4500 R gas temperature, tube buckling, and susceptibility to erosion. The scope of the analysis is limited to processes leading to reliability assessments of failure mechanisms.

  10. Remtech SSME nozzle design TPS

    NASA Astrophysics Data System (ADS)

    Bancroft, Steven A.; Engel, Carl D.; Pond, John E.

    1990-09-01

    Thermal damage to the Space Shuttle Main Engine (SSME) aft manifold Thermal Protection System (TPS) has been observed for flights STS-8 through STS-13. This damaged area is located on the ME2 and ME3 and extends over a region of approximately one square foot. Total failure or burn-through of the TPS could lead to severe thermal damage of the SSME manifold and loss of an engine nozzle necessitating nozzle replacement causing significant schedule delays and cost increases. Thermal damage to the manifold can be defined as a situation where the manifold temperature becomes greater than 1300 F; thereby causing loss of heat treatment in the nozzle. Results of Orbiter/nozzle wind tunnel tests and Hot Gas Facility tests of the TPS are presented. Aerothermal and thermal analysis models for the SSME aft manifold are discussed along with the flight predictions, design trajectory and design environment. Finally, the TPS design concept and TPS thermal response are addressed.

  11. Fact Program - distributed exhaust nozzle

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Futuristic Airframe Concepts & Technology (FACT): Distributed exhaust nozzle mounted in the Low Speed Aeroacoustic Wind Tunnel. Angle is zero degrees with respect to microphones. Photographed in the Low Speed Aeroacoustic Wind Tunnel, Jet Noise Lab, building 1221-A.

  12. Evaporation Tower With Prill Nozzles

    NASA Technical Reports Server (NTRS)

    Du Fresne, E. R.

    1984-01-01

    Tower more efficient than conventional evaporation equipment. Liquids such as milk and fruit juice concentrated by passing them through tiny nozzle to form droplets, then allowing droplets to fall through evacuated tower with cooled walls.

  13. Remtech SSME nozzle design TPS

    NASA Technical Reports Server (NTRS)

    Bancroft, Steven A.; Engel, Carl D.; Pond, John E.

    1990-01-01

    Thermal damage to the Space Shuttle Main Engine (SSME) aft manifold Thermal Protection System (TPS) has been observed for flights STS-8 through STS-13. This damaged area is located on the ME2 and ME3 and extends over a region of approximately one square foot. Total failure or burn-through of the TPS could lead to severe thermal damage of the SSME manifold and loss of an engine nozzle necessitating nozzle replacement causing significant schedule delays and cost increases. Thermal damage to the manifold can be defined as a situation where the manifold temperature becomes greater than 1300 F; thereby causing loss of heat treatment in the nozzle. Results of Orbiter/nozzle wind tunnel tests and Hot Gas Facility tests of the TPS are presented. Aerothermal and thermal analysis models for the SSME aft manifold are discussed along with the flight predictions, design trajectory and design environment. Finally, the TPS design concept and TPS thermal response are addressed.

  14. Reactor pressure vessel nozzle

    DOEpatents

    Challberg, Roy C.; Upton, Hubert A.

    1994-01-01

    A nozzle for joining a pool of water to a nuclear reactor pressure vessel includes a tubular body having a proximal end joinable to the pressure vessel and a distal end joinable in flow communication with the pool. The body includes a flow passage therethrough having in serial flow communication a first port at the distal end, a throat spaced axially from the first port, a conical channel extending axially from the throat, and a second port at the proximal end which is joinable in flow communication with the pressure vessel. The inner diameter of the flow passage decreases from the first port to the throat and then increases along the conical channel to the second port. In this way, the conical channel acts as a diverging channel or diffuser in the forward flow direction from the first port to the second port for recovering pressure due to the flow restriction provided by the throat. In the backflow direction from the second port to the first port, the conical channel is a converging channel and with the abrupt increase in flow area from the throat to the first port collectively increase resistance to flow therethrough.

  15. Reactor pressure vessel nozzle

    DOEpatents

    Challberg, R.C.; Upton, H.A.

    1994-10-04

    A nozzle for joining a pool of water to a nuclear reactor pressure vessel includes a tubular body having a proximal end joinable to the pressure vessel and a distal end joinable in flow communication with the pool. The body includes a flow passage therethrough having in serial flow communication a first port at the distal end, a throat spaced axially from the first port, a conical channel extending axially from the throat, and a second port at the proximal end which is joinable in flow communication with the pressure vessel. The inner diameter of the flow passage decreases from the first port to the throat and then increases along the conical channel to the second port. In this way, the conical channel acts as a diverging channel or diffuser in the forward flow direction from the first port to the second port for recovering pressure due to the flow restriction provided by the throat. In the backflow direction from the second port to the first port, the conical channel is a converging channel and with the abrupt increase in flow area from the throat to the first port collectively increase resistance to flow therethrough. 2 figs.

  16. Flux Compression Magnetic Nozzle

    NASA Technical Reports Server (NTRS)

    Thio, Y. C. Francis; Schafer, Charles (Technical Monitor)

    2001-01-01

    In pulsed fusion propulsion schemes in which the fusion energy creates a radially expanding plasma, a magnetic nozzle is required to redirect the radially diverging flow of the expanding fusion plasma into a rearward axial flow, thereby producing a forward axial impulse to the vehicle. In a highly electrically conducting plasma, the presence of a magnetic field B in the plasma creates a pressure B(exp 2)/2(mu) in the plasma, the magnetic pressure. A gradient in the magnetic pressure can be used to decelerate the plasma traveling in the direction of increasing magnetic field, or to accelerate a plasma from rest in the direction of decreasing magnetic pressure. In principle, ignoring dissipative processes, it is possible to design magnetic configurations to produce an 'elastic' deflection of a plasma beam. In particular, it is conceivable that, by an appropriate arrangement of a set of coils, a good approximation to a parabolic 'magnetic mirror' may be formed, such that a beam of charged particles emanating from the focal point of the parabolic mirror would be reflected by the mirror to travel axially away from the mirror. The degree to which this may be accomplished depends on the degree of control one has over the flux surface of the magnetic field, which changes as a result of its interaction with a moving plasma.

  17. High Pressure Water Stripping Using Multi-Orifice Nozzles

    NASA Technical Reports Server (NTRS)

    Hoppe, David T.

    1998-01-01

    The use of multi-orifice rotary nozzles not only increases the speed and stripping effectiveness of high pressure water blasting systems, but also greatly increases the complexity of selecting and optimizing the operating parameters. The rotational speed of the nozzle must be coupled with the transverse velocity of the nozzle as it passes across the surface of the substrate being stripped. The radial and angular positions of each orifice must be included in the analysis of the nozzle configuration. Since orifices at the outer edge of the nozzle head move at a faster rate than the orifice located near the center, the energy impact force of the water stream from the outer orifice is spread over a larger area than the water streams from the inner orifice. Utilizing a larger diameter orifice in the outer radial positions increases the energy impact to compensate for its wider force distribution. The total flow rate from the combination of orifices must be monitored and kept below the pump capacity while choosing an orifice to insert in each position. The energy distribution from the orifice pattern is further complicated since the rotary path of all orifices in the nozzle head pass through the center section, contributing to the stripping in this area while only the outer most orifice contributes to the stripping in the shell area at the extreme outside edge of the nozzle. From t he outer most shell to the center section, more orifices contribute to the stripping in each progressively reduced diameter shell. With all these parameters to configure and each parameter change affecting the others, a computer model was developed to track and coordinate these parameters. The computer simulation responds by graphically indicating the cumulative affect from each parameter selected. The results from the proper choices in parameters is a well designed, highly efficient stripping system. A poorly chosen set of parameters will cause the nozzle to strip aggressively in some areas

  18. Carbon/Carbon extendible Nozzles

    NASA Astrophysics Data System (ADS)

    Lacoste, M.; Lacombe, A.; Joyez, P.; Ellis, R. A.; Lee, J. C.; Payne, F. M.

    2002-03-01

    For many years, SEP has developed C-C composite materials to lighten architectures of propulsion systems, thanks to their high specific mechanical properties kept up to about 2500°C. The 3D carbon reinforcement the so-called Novoltex ® has emerged, and today more than 150 tons per year of C-C is produced by SEP using it. The advent of these thermostructural composite materials have blazed a trail for innovative solutions applicable to the extreme operating conditions of large rocket engines, to improve their performances. The extendible nozzle concept has been developed to optimize the expansion ratio with regard to size restriction required particularly for the upper stages of launchers. The first two tests of a SEP extendible nozzle extension were carried out in 1979, one on a ring design and one on a panel design. Today, nearly all possible configurations have been tested, from the simple scenario of extending a ring from a fixed nozzle prior to ignition, to the most complex one: nozzle deployment while the motor is operating and when the nozzle is being vectored. In August 1995, Pratt & Whitney have entrusted SEP with the development of the C-C exit cone dedicated to the RL10 B-2 cryotechnic engine, propulsion system of the DELTA III upper stage. One year later, in August 1996, SEP delivered the first development item which is currently under testing. When the entire C-C nozzle is attached to the RL10 B-2 engine and deployed, the nozzle diameter increases from 1.1 to 2.1 m and translates to 2.5 m in length, providing an expansion ratio of 285:1 and 30 s of specific impulse increase to the engine. Finally, the paper will describe the design and manufacturing of this huge exit cone and will report the latest test results.

  19. SHINE Tritium Nozzle Design: Activity 6, Task 1 Report

    SciTech Connect

    Okhuysen, Brett S.; Pulliam, Elias Noel

    2015-11-05

    In FY14, we studied the qualitative and quantitative behavior of a SHINE/PNL tritium nozzle under varying operating conditions. The result is an understanding of the nozzle’s performance in terms of important flow features that manifest themselves under different parametric profiles. In FY15, we will consider nozzle design with a focus on nozzle geometry and integration. From FY14 work, we will understand how the SHINE/PNL nozzle behaves under different operating scenarios. The first task for FY15 is to evaluate the FY14 model as a predictor of the actual flow. Considering different geometries is more time-intensive than parameter studies, therefore we recommend considering any relevant flow features that were not included in the FY14 model. In the absence of experimental data, it is particularly important to consider any sources of heat in the domain or boundary conditions that may affect the flow and incorporate these into the simulation if they are significant. Additionally, any geometric features of the beamline segment should be added to the model such as the orifice plate. The FY14 model works with hydrogen. An improvement that can be made for FY15 is to develop CFD properties for tritium and incorporate those properties into the new models.

  20. Investigating an annular nozzle on combustion products of hydrocarbon fuels

    NASA Astrophysics Data System (ADS)

    Levin, V. A.; Afonina, N. E.; Gromov, V. G.; Smekhov, G. D.; Khmelevsky, A. N.; Markov, V. V.

    2013-09-01

    Full-scale and computational experiments were used to investigate the flows in the jet thrust unit with annular nozzle and deflector in the form of a spherical segment. The used working gas was the combustion products of air mixtures with acetylene, gas-phase aviation kerosene, and natural gas. Experimental studies were carried out in a hot-shot wind tunnel in the range of stagnation pressure from 0.48 to 2.05 MPa. The calculations for the cases of combustion products outflow in terrestrial and high altitude conditions were performed with the original computer program that used the Euler and Navier-Stokes systems supplemented by equations of chemical kinetics. It was found that the thrust of the jet module with an annular nozzle at high altitude almost twice exceeds the sound nozzle thrust, but is lesser (about 25 %) than the thrust of the ideal calculated Laval nozzle; the difference therewith decreases markedly with the decrease of flight altitude and stagnation pressure.

  1. Alternate nozzle ablative materials program

    NASA Technical Reports Server (NTRS)

    Kimmel, N. A.

    1984-01-01

    Four subscale solid rocket motor tests were conducted successfully to evaluate alternate nozzle liner, insulation, and exit cone structural overwrap components for possible application to the Space Shuttle Solid Rocket Motor (SRM) nozzle asasembly. The 10,000 lb propellant motor tests were simulated, as close as practical, the configuration and operational environment of the full scale SRM. Fifteen PAN based and three pitch based materials had no filler in the phenolic resin, four PAN based materials had carbon microballoons in the resin, and the rest of the materials had carbon powder in the resin. Three nozzle insulation materials were evaluated; an aluminum oxide silicon oxide ceramic fiber mat phenolic material with no resin filler and two E-glass fiber mat phenolic materials with no resin filler. It was concluded by MTI/WD (the fabricator and evaluator of the test nozzles) and NASA-MSFC that it was possible to design an alternate material full scale SRM nozzle assembly, which could provide an estimated 360 lb increased payload capability for Space Shuttle launches over that obtainable with the current qualified SRM design.

  2. Cervical facet dislocation adjacent to the fused motion segment

    PubMed Central

    Yokoyama, Kunio; Kawanishi, Masahiro; Yamada, Makoto; Tanaka, Hidekazu; Ito, Yutaka; Kuroiwa, Toshihiko

    2016-01-01

    This study reports on a case that forces re-examination of merits and demerits of anterior cervical fusion. A 79-year-old male was brought to the emergency room (ER) of our hospital after he fell and struck the occipital region of his head following excessive alcohol consumption. Four years prior, he had undergone anterior cervical discectomy and fusion of C5/6 and a magnetic resonance imaging (MRI) performed 3 years after this surgery indicated that he was suffering from degeneration of C6/7 intervertebral discs. After arriving at the ER, he presented motor impairment at level C7 and lower of manual muscle testing grade 1 as well as moderate loss of physical sensation from the trunk and peripheries of both upper limbs to the peripheries of both lower limbs (Frankel B). Cervical computed tomography (CT) indicated anterior dislocation of C6/7, and MRI indicated severe spinal cord edema. We performed manipulative reduction of C6/7 with the patient under general anesthesia. Next, we performed laminectomy on C5-T1 and posterior fusion on C6/7. Postoperative CT indicated that cervical alignment had improved, and MRI indicated that the spinal cord edema observed prior to surgery had been mitigated. Three months after surgery, motor function and sensory impairment of the lower limbs had improved, and the patient was ambulatory upon discharge from the hospital (Frankel D). In the present case, although C5 and 6 were rigidly fused, degeneration of the C6/7 intervertebral disc occurred and stability was compromised. As a result, even slight trauma placed a severe dynamic burden on the facet joint of C6/7, which led to dislocation. PMID:26933361

  3. Cervical facet dislocation adjacent to the fused motion segment.

    PubMed

    Yokoyama, Kunio; Kawanishi, Masahiro; Yamada, Makoto; Tanaka, Hidekazu; Ito, Yutaka; Kuroiwa, Toshihiko

    2016-01-01

    This study reports on a case that forces re-examination of merits and demerits of anterior cervical fusion. A 79-year-old male was brought to the emergency room (ER) of our hospital after he fell and struck the occipital region of his head following excessive alcohol consumption. Four years prior, he had undergone anterior cervical discectomy and fusion of C5/6 and a magnetic resonance imaging (MRI) performed 3 years after this surgery indicated that he was suffering from degeneration of C6/7 intervertebral discs. After arriving at the ER, he presented motor impairment at level C7 and lower of manual muscle testing grade 1 as well as moderate loss of physical sensation from the trunk and peripheries of both upper limbs to the peripheries of both lower limbs (Frankel B). Cervical computed tomography (CT) indicated anterior dislocation of C6/7, and MRI indicated severe spinal cord edema. We performed manipulative reduction of C6/7 with the patient under general anesthesia. Next, we performed laminectomy on C5-T1 and posterior fusion on C6/7. Postoperative CT indicated that cervical alignment had improved, and MRI indicated that the spinal cord edema observed prior to surgery had been mitigated. Three months after surgery, motor function and sensory impairment of the lower limbs had improved, and the patient was ambulatory upon discharge from the hospital (Frankel D). In the present case, although C5 and 6 were rigidly fused, degeneration of the C6/7 intervertebral disc occurred and stability was compromised. As a result, even slight trauma placed a severe dynamic burden on the facet joint of C6/7, which led to dislocation. PMID:26933361

  4. Nozzle geometry for organic vapor jet printing

    DOEpatents

    Forrest, Stephen R; McGraw, Gregory

    2015-01-13

    A first device is provided. The device includes a print head. The print head further includes a first nozzle hermetically sealed to a first source of gas. The first nozzle has an aperture having a smallest dimension of 0.5 to 500 microns in a direction perpendicular to a flow direction of the first nozzle. At a distance from the aperture into the first nozzle that is 5 times the smallest dimension of the aperture of the first nozzle, the smallest dimension perpendicular to the flow direction is at least twice the smallest dimension of the aperture of the first nozzle.

  5. Advanced high area ratio nozzles

    NASA Technical Reports Server (NTRS)

    Raiszadeh, Farhad; Collins, Frank G.; Orr, Joseph L., Jr.; Myruski, Brian

    1995-01-01

    The objective is to develop computational techniques for the design of high-area-ratio nozzles and to validate these models by comparison with experiments and computations using other codes. Progress was made in two areas during the past year. First, performance computations were added to the PARC2D code and the performance of the SSME nozzle was computed for inviscid, laminar and turbulent flow assuming a perfect gas with gamma = 1.2. Second, the PARC2D code was modified in a non-CASP project to compute equilibrium flow about hypersonic blunt bodies. Progress has been made toward modifying this code to compute equilibrium H2/O2 flow through the SSME and related nozzles.

  6. Advanced high area ratio nozzles

    NASA Technical Reports Server (NTRS)

    Raiszadeh, Farhad; Collins, Frank G.; Orr, Joseph L., Jr.; Myruski, Brian

    1989-01-01

    The objective is to develop computational techniques for the design of high-area-ratio nozzles and to validate these models by comparison with experiments and computations using other codes. Performance computations were added to the PARC2D code and the performance of the space shuttle main engine (SSME) nozzle was computed for inviscid, laminar and turbulent flow assuming a perfect gas with gamma = 1.2. The PARC2D code was modified in a non-CASP (Center for Advanced Space Propulsion) project to compute equilibrium flow about hypersonic blunt bodies. Progress has been made toward modifying this code to compute equilibrium H2/O2 flow through the SSME and related nozzles.

  7. Flame tolerant secondary fuel nozzle

    SciTech Connect

    Khan, Abdul Rafey; Ziminsky, Willy Steve; Wu, Chunyang; Zuo, Baifang; Stevenson, Christian Xavier

    2015-02-24

    A combustor for a gas turbine engine includes a plurality of primary nozzles configured to diffuse or premix fuel into an air flow through the combustor; and a secondary nozzle configured to premix fuel with the air flow. Each premixing nozzle includes a center body, at least one vane, a burner tube provided around the center body, at least two cooling passages, a fuel cooling passage to cool surfaces of the center body and the at least one vane, and an air cooling passage to cool a wall of the burner tube. The cooling passages prevent the walls of the center body, the vane(s), and the burner tube from overheating during flame holding events.

  8. Prototype Morphing Fan Nozzle Demonstrated

    NASA Technical Reports Server (NTRS)

    Lee, Ho-Jun; Song, Gang-Bing

    2004-01-01

    Ongoing research in NASA Glenn Research Center's Structural Mechanics and Dynamics Branch to develop smart materials technologies for aeropropulsion structural components has resulted in the design of the prototype morphing fan nozzle shown in the photograph. This prototype exploits the potential of smart materials to significantly improve the performance of existing aircraft engines by introducing new inherent capabilities for shape control, vibration damping, noise reduction, health monitoring, and flow manipulation. The novel design employs two different smart materials, a shape-memory alloy and magnetorheological fluids, to reduce the nozzle area by up to 30 percent. The prototype of the variable-area fan nozzle implements an overlapping spring leaf assembly to simplify the initial design and to provide ease of structural control. A single bundle of shape memory alloy wire actuators is used to reduce the nozzle geometry. The nozzle is subsequently held in the reduced-area configuration by using magnetorheological fluid brakes. This prototype uses the inherent advantages of shape memory alloys in providing large induced strains and of magnetorheological fluids in generating large resistive forces. In addition, the spring leaf design also functions as a return spring, once the magnetorheological fluid brakes are released, to help force the shape memory alloy wires to return to their original position. A computerized real-time control system uses the derivative-gain and proportional-gain algorithms to operate the system. This design represents a novel approach to the active control of high-bypass-ratio turbofan engines. Researchers have estimated that such engines will reduce thrust specific fuel consumption by 9 percent over that of fixed-geometry fan nozzles. This research was conducted under a cooperative agreement (NCC3-839) at the University of Akron.

  9. THE TRUSS BRIDGE SEGMENT OF THE TRIBOROUGH BRIDGE IN FOREGROUND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    THE TRUSS BRIDGE SEGMENT OF THE TRIBOROUGH BRIDGE IN FOREGROUND AND THE HELL GATE BRIDGE IN THE BACKGROUND ADJACENT TO THE SUSPENSION SEGMENT OF THE TRIBOROUGH BRIDGE. - Triborough Bridge, Passing through Queens, Manhattan & the Bronx, Queens (subdivision), Queens County, NY

  10. Nozzle for superconducting fiber production

    DOEpatents

    Righi, Jamal

    1992-11-17

    A nozzle apparatus for producing flexible fibers of superconducting material receives melted material from a crucible for containing a charge of the superconducting material. The material is melted in the crucible and falls in a stream through a bottom hole in the crucible. The stream falls through a protecting collar which maintains the stream at high temperatures. The stream is then supplied through the downwardly directed nozzle where it is subjected to a high velocity air flow which breaks the melted superconducting material into ligaments which solidify into the flexible fibers. The fibers are collected by blowing them against a porous cloth.

  11. Development of Air Speed Nozzles

    NASA Technical Reports Server (NTRS)

    Zahm, A F

    1920-01-01

    Report describes the development of a suitable speed nozzle for the first few thousand airplanes made by the United States during the recent war in Europe, and to furnish a basis for more mature instruments in the future. Requirements for the project were to provide a suitable pressure collector for aircraft speed meters and to develop a speed nozzle which would be waterproof, powerful, unaffected by slight pitch and yaw, rugged and easy to manufacture, and uniform in structure and reading, so as not to require individual calibration.

  12. Linear nozzle with tailored gas plumes

    DOEpatents

    Kozarek, Robert L.; Straub, William D.; Fischer, Joern E.; Leon, David D.

    2003-01-01

    There is claimed a method for depositing fluid material from a linear nozzle in a substantially uniform manner across and along a surface. The method includes directing gaseous medium through said nozzle to provide a gaseous stream at the nozzle exit that entrains fluid material supplied to the nozzle, said gaseous stream being provided with a velocity profile across the nozzle width that compensates for the gaseous medium's tendency to assume an axisymmetric configuration after leaving the nozzle and before reaching the surface. There is also claimed a nozzle divided into respective side-by-side zones, or preferably chambers, through which a gaseous stream can be delivered in various velocity profiles across the width of said nozzle to compensate for the tendency of this gaseous medium to assume an axisymmetric configuration.

  13. Linear nozzle with tailored gas plumes

    DOEpatents

    Leon, David D.; Kozarek, Robert L.; Mansour, Adel; Chigier, Norman

    2001-01-01

    There is claimed a method for depositing fluid material from a linear nozzle in a substantially uniform manner across and along a surface. The method includes directing gaseous medium through said nozzle to provide a gaseous stream at the nozzle exit that entrains fluid material supplied to the nozzle, said gaseous stream being provided with a velocity profile across the nozzle width that compensates for the gaseous medium's tendency to assume an axisymmetric configuration after leaving the nozzle and before reaching the surface. There is also claimed a nozzle divided into respective side-by-side zones, or preferably chambers, through which a gaseous stream can be delivered in various velocity profiles across the width of said nozzle to compensate for the tendency of this gaseous medium to assume an axisymmetric configuration.

  14. Design of supersonic Coanda jet nozzles

    NASA Technical Reports Server (NTRS)

    Bevilaqua, Paul M.; Lee, John D.

    1987-01-01

    The thrust vectoring of supersonic Coanda jets was improved by designing a nozzle to skew the initial jet velocity profile. A new nozzle design procedure, based on the method of characteristics, was developed to design a nozzle which produces a specified exit velocity profile. The thrust vectoring of a simple convergent nozzle, a convergent-divergent nozzle, and a nozzle which produces a skewed velocity profile matched to the curvature of the Coanda surface were expermentially compared over a range of pressure ratios from 1.5 to 3.5. Elimination of the expansion shocks with the C-D nozzle is shown to greatly improve the thrust vectoring; elimination of turning shocks with the skewed profile nozzle further improves the vectoring.

  15. 46 CFR 154.1120 - Nozzles.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Nozzles. (a) Nozzles for the water spray system must be spaced to provide the minimum discharge density under § 154.1115 in each part of the protected area. (b) The vertical distance between water...

  16. 46 CFR 154.1120 - Nozzles.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Nozzles. (a) Nozzles for the water spray system must be spaced to provide the minimum discharge density under § 154.1115 in each part of the protected area. (b) The vertical distance between water...

  17. 46 CFR 154.1120 - Nozzles.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Nozzles. (a) Nozzles for the water spray system must be spaced to provide the minimum discharge density under § 154.1115 in each part of the protected area. (b) The vertical distance between water...

  18. Computer aided design study of hypermixing nozzles

    NASA Technical Reports Server (NTRS)

    Mefferd, L. A.; Bevilacqua, P. M.

    1979-01-01

    The development of a nozzle which combines the hypermixing and lobe mechanisms to achieve further increases in jet entrainment and ejector performance is investigated. A computer program which incorporates a two equation turbulence model and is used to predict and compare the evolution of jets from various nozzle designs is discussed. Increasing the length of the nozzle lobes and an alternating lobe nozzle are a methods examined for increasing the entrainment rate.

  19. Nozzle Extension for Safety Air Gun

    NASA Technical Reports Server (NTRS)

    Zumbrun, H. N.; Croom, Delwin R., Jr.

    1986-01-01

    New nozzle-extension design overcomes problems and incorporates original commercial nozzle, retaining intrinsic safety features. Components include extension tube, length of which made to suit application; adaptor fitting, and nozzle adaptor repinned to maintain original safety features. Design moves conical airstream to end of extension to blow machine chips away from operator. Nozzle-extension modification allows safe and efficient operation of machine tools while maintaining integrity of orginial safety-air-gun design.

  20. Perfect bell nozzle parametric and optimization curves

    NASA Technical Reports Server (NTRS)

    Tuttle, J. L.; Blount, D. H.

    1983-01-01

    Nozzle contour data for untruncated Bell nozzles with expansion area ratios to 6100 and a specific heat ratio of 1.2 are provided. Curves for optimization of nozzles for maximum thrust coefficient within a given length, surface area, or area ratio are included. The nozzles are two dimensional axisymmetric and calculations were performed using the method of characteristics. Drag due to wall friction was included in the final thrust coefficient.

  1. High Pressure Water Stripping Using Multi-Orifice Nozzles

    NASA Technical Reports Server (NTRS)

    Hoppe, David

    1999-01-01

    The use of multi-orifice rotary nozzles greatly increases the speed and stripping effectiveness of high pressure water blasting systems, but also greatly increases the complexity of selecting and optimizing the operating parameters. The rotational speed of the nozzle must be coupled with its transverse velocity as it passes across the surface of the substrate being stripped. The radial and angular positions of each orifice must be included in the analysis of the nozzle configuration. Orifices at the outer edge of the nozzle head move at a faster rate than the orifices located near the center. The energy transmitted to the surface from the impact force of the water stream from an outer orifice is therefore spread over a larger area than energy from an inner orifice. Utilizing a larger diameter orifice in the outer radial positions increases the total energy transmitted from the outer orifice to compensate for the wider distribution of energy. The total flow rate from the combination of all orifices must be monitored and should be kept below the pump capacity while choosing orifice to insert in each position. The energy distribution from the orifice pattern is further complicated since the rotary path of all the orifices in the nozzle head pass through the center section. All orifices contribute to the stripping in the center of the path while only the outer most orifice contributes to the stripping at the edge of the nozzle. Additional orifices contribute to the stripping from the outer edge toward the center section. With all these parameters to configure and each parameter change affecting the others, a computer model was developed to track and coordinate these parameters. The computer simulation graphically indicates the cumulative affect from each parameter selected. The result from the proper choices in parameters is a well designed, highly efficient stripping system. A poorly chosen set of parameters will cause the nozzle to strip aggressively in some areas

  2. ADDITIONAL STRESS AND FRACTURE MECHANICS ANALYSES OF PRESSURIZED WATER REACTOR PRESSURE VESSEL NOZZLES

    SciTech Connect

    Walter, Matthew; Yin, Shengjun; Stevens, Gary; Sommerville, Daniel; Palm, Nathan; Heinecke, Carol

    2012-01-01

    In past years, the authors have undertaken various studies of nozzles in both boiling water reactors (BWRs) and pressurized water reactors (PWRs) located in the reactor pressure vessel (RPV) adjacent to the core beltline region. Those studies described stress and fracture mechanics analyses performed to assess various RPV nozzle geometries, which were selected based on their proximity to the core beltline region, i.e., those nozzle configurations that are located close enough to the core region such that they may receive sufficient fluence prior to end-of-life (EOL) to require evaluation of embrittlement as part of the RPV analyses associated with pressure-temperature (P-T) limits. In this paper, additional stress and fracture analyses are summarized that were performed for additional PWR nozzles with the following objectives: To expand the population of PWR nozzle configurations evaluated, which was limited in the previous work to just two nozzles (one inlet and one outlet nozzle). To model and understand differences in stress results obtained for an internal pressure load case using a two-dimensional (2-D) axi-symmetric finite element model (FEM) vs. a three-dimensional (3-D) FEM for these PWR nozzles. In particular, the ovalization (stress concentration) effect of two intersecting cylinders, which is typical of RPV nozzle configurations, was investigated. To investigate the applicability of previously recommended linear elastic fracture mechanics (LEFM) hand solutions for calculating the Mode I stress intensity factor for a postulated nozzle corner crack for pressure loading for these PWR nozzles. These analyses were performed to further expand earlier work completed to support potential revision and refinement of Title 10 to the U.S. Code of Federal Regulations (CFR), Part 50, Appendix G, Fracture Toughness Requirements, and are intended to supplement similar evaluation of nozzles presented at the 2008, 2009, and 2011 Pressure Vessels and Piping (PVP

  3. 1. OVERVIEW SHOWING FIRING CONTROL BLOCKHOUSE 0502 AND ADJACENT OBSERVATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. OVERVIEW SHOWING FIRING CONTROL BLOCKHOUSE 0502 AND ADJACENT OBSERVATION TOWER. WATER BRAKE TROUGH SEGMENT AT LOWER RIGHT. Looking north northeast. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA

  4. Turbomachine combustor nozzle including a monolithic nozzle component and method of forming the same

    DOEpatents

    Stoia, Lucas John; Melton, Patrick Benedict; Johnson, Thomas Edward; Stevenson, Christian Xavier; Vanselow, John Drake; Westmoreland, James Harold

    2016-02-23

    A turbomachine combustor nozzle includes a monolithic nozzle component having a plate element and a plurality of nozzle elements. Each of the plurality of nozzle elements includes a first end extending from the plate element to a second end. The plate element and plurality of nozzle elements are formed as a unitary component. A plate member is joined with the nozzle component. The plate member includes an outer edge that defines first and second surfaces and a plurality of openings extending between the first and second surfaces. The plurality of openings are configured and disposed to register with and receive the second end of corresponding ones of the plurality of nozzle elements.

  5. Kinetic energy of rainfall simulation nozzles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Different spray nozzles are used frequently to simulate natural rain for soil erosion and chemical transport, particularly phosphorous (P), studies. Oscillating VeeJet nozzles are used mostly in soil erosion research while constant spray FullJet nozzles are commonly used for P transport. Several ch...

  6. Reactor pressure vessel with forged nozzles

    DOEpatents

    Desai, Dilip R.

    1993-01-01

    Inlet nozzles for a gravity-driven cooling system (GDCS) are forged with a cylindrical reactor pressure vessel (RPV) section to which a support skirt for the RPV is attached. The forging provides enhanced RPV integrity around the nozzle and substantial reduction of in-service inspection costs by eliminating GDCS nozzle-to-RPV welds.

  7. Nozzle for electric dispersion reactor

    DOEpatents

    Sisson, W.G.; Harris, M.T.; Scott, T.C.; Basaran, O.A.

    1996-04-02

    A nozzle for an electric dispersion reactor includes two coaxial cylindrical bodies, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode. 5 figs.

  8. Nozzle for electric dispersion reactor

    DOEpatents

    Sisson, W.G.; Basaran, O.A.; Harris, M.T.

    1995-11-07

    A nozzle for an electric dispersion reactor includes two concentric electrodes, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode. 4 figs.

  9. Nozzle for electric dispersion reactor

    DOEpatents

    Sisson, W.G.; Harris, M.T.; Scott, T.C.; Basaran, O.A.

    1998-06-02

    A nozzle for an electric dispersion reactor includes two coaxial cylindrical bodies, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode. 5 figs.

  10. Nozzle for electric dispersion reactor

    DOEpatents

    Sisson, Warren G.; Harris, Michael T.; Scott, Timothy C.; Basaran, Osman A.

    1998-01-01

    A nozzle for an electric dispersion reactor includes two coaxial cylindrical bodies, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode.

  11. Nozzle for electric dispersion reactor

    DOEpatents

    Sisson, Warren G.; Harris, Michael T.; Scott, Timothy C.; Basaran, Osman A.

    1996-01-01

    A nozzle for an electric dispersion reactor includes two coaxial cylindrical bodies, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode.

  12. Nozzle for electric dispersion reactor

    DOEpatents

    Sisson, Warren G.; Basaran, Osman A.; Harris, Michael T.

    1995-01-01

    A nozzle for an electric dispersion reactor includes two concentric electrodes, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode.

  13. Nozzle for electric dispersion reactor

    DOEpatents

    Sisson, W.G.; Basaran, O.A.; Harris, M.T.

    1998-04-14

    A nozzle for an electric dispersion reactor includes two concentric electrodes, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode. 4 figs.

  14. Nozzle for electric dispersion reactor

    DOEpatents

    Sisson, Warren G.; Basaran, Osman A.; Harris, Michael T.

    1998-01-01

    A nozzle for an electric dispersion reactor includes two concentric electrodes, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode.

  15. Altitude Compensating Nozzle Concepts Evaluation

    NASA Technical Reports Server (NTRS)

    Soni, Bharat

    2000-01-01

    This report contains the summary of work accomplished during summer of 2000 by Mr. Chad Hammons, undergraduate senior student, Mississippi State University/ERC in support of NASA/MSFC mission pertinent to Altitude compensating nozzle concepts evaluations. In particular, the development of automatic grid generator applicable in conducting sensitivity analysis involving Aerospike engine is described.

  16. A Novel Machine Vision System for the Inspection of Micro-Spray Nozzle

    PubMed Central

    Huang, Kuo-Yi; Ye, Yu-Ting

    2015-01-01

    In this study, we present an application of neural network and image processing techniques for detecting the defects of an internal micro-spray nozzle. The defect regions were segmented by Canny edge detection, a randomized algorithm for detecting circles and a circle inspection (CI) algorithm. The gray level co-occurrence matrix (GLCM) was further used to evaluate the texture features of the segmented region. These texture features (contrast, entropy, energy), color features (mean and variance of gray level) and geometric features (distance variance, mean diameter and diameter ratio) were used in the classification procedures. A back-propagation neural network classifier was employed to detect the defects of micro-spray nozzles. The methodology presented herein effectively works for detecting micro-spray nozzle defects to an accuracy of 90.71%. PMID:26131678

  17. A Novel Machine Vision System for the Inspection of Micro-Spray Nozzle.

    PubMed

    Huang, Kuo-Yi; Ye, Yu-Ting

    2015-01-01

    In this study, we present an application of neural network and image processing techniques for detecting the defects of an internal micro-spray nozzle. The defect regions were segmented by Canny edge detection, a randomized algorithm for detecting circles and a circle inspection (CI) algorithm. The gray level co-occurrence matrix (GLCM) was further used to evaluate the texture features of the segmented region. These texture features (contrast, entropy, energy), color features (mean and variance of gray level) and geometric features (distance variance, mean diameter and diameter ratio) were used in the classification procedures. A back-propagation neural network classifier was employed to detect the defects of micro-spray nozzles. The methodology presented herein effectively works for detecting micro-spray nozzle defects to an accuracy of 90.71%. PMID:26131678

  18. Distributed Exhaust Nozzles for Jet Noise Reduction

    NASA Technical Reports Server (NTRS)

    Ahuja, K. K.; Gaeta, R. J.; Hellman, B.; Schein, D. B.; Solomon, W. D., Jr.; Huff, Dennis (Technical Monitor)

    2001-01-01

    The main objective of this study is to validate the jet noise reduction potential of a concept associated with distributed exhaust nozzles. Under this concept the propulsive thrust is generated by a larger number of discrete plumes issuing from an array of small or mini-nozzles. The potential of noise reduction of this concept stems from the fact that a large number of small jets will produce very high frequency noise and also, if spaced suitably, they will coalesce at a smaller velocity to produce low amplitude, low frequency noise. This is accomplished through detailed acoustic and fluid measurements along with a Computational Fluidic Dynamic (CFD) solution of the mean (DE) Distributed Exhaust nozzle flowfield performed by Northrop-Grumman. The acoustic performance is quantified in an anechoic chamber. Farfield acoustic data is acquired for a DE nozzle as well as a round nozzle of the same area. Both these types of nozzles are assessed numerically using Computational Fluid Dynamic (CFD) techniques. The CFD analysis ensures that both nozzles issued the same amount of airflow for a given nozzle pressure ratio. Data at a variety of nozzle pressure ratios are acquired at a range of polar and azimuthal angles. Flow visualization of the DE nozzle is used to assess the fluid dynamics of the small jet interactions. Results show that at high subsonic jet velocities, the DE nozzle shifts its frequency of peak amplitude to a higher frequency relative to a round nozzle of equivalent area (from a S(sub tD) = 0.24 to 1. 3). Furthermore, the DE nozzle shows reduced sound pressure levels (as much as 4 - 8 dB) in the low frequency part of the spectrum (less than S(sub tD) = 0.24 ) compared to the round nozzle. At supersonic jet velocities, the DE nozzle does not exhibit the jet screech and the shock-associated broadband noise is reduced by as much as 12 dB.

  19. Experimental characterization of spin motor nozzle flow.

    SciTech Connect

    Erven, Rocky J.; Peterson, Carl Williams; Henfling, John Francis

    2006-11-01

    The Mach number in the inviscid core of the flow exiting scarfed supersonic nozzles was measured using pitot probes. Nozzle characterization experiments were conducted in a modified section of an obsolete M = 7.3 test section/nozzle assembly on Sandia's Hypersonic Wind Tunnel. By capitalizing on existing hardware, the cost and time required for tunnel modifications were significantly reduced. Repeatability of pitot pressure measurements was excellent, and instrumentation errors were reduced by optimizing the pressure range of the transducers used for each test run. Bias errors in probe position prevented us from performing a successful in situ calibration of probe angle effects using pitot probes placed at an angle to the nozzle centerline. The abrupt throat geometry used in the Baseline and Configuration A and B nozzles modeled the throat geometry of the flight vehicle's spin motor nozzles. Survey data indicates that small (''unmeasurable'') differences in the nozzle throat geometries produced measurable flow asymmetries and differences in the flow fields generated by supposedly identical nozzles. Therefore, data from the Baseline and Configuration A and B nozzles cannot be used for computational fluid dynamics (CFD) code validation. Configuration C and D nozzles replaced the abrupt throat geometry of Baseline and Configuration A and B nozzles with a 0.500-inch streamwise radius of curvature in the throat region. This throat geometry eliminated the flow asymmetries, flow separation in the nozzle throat, and measurable differences between the flow fields from identical nozzles that were observed in Baseline/A/B nozzles. Data from Configuration C and D nozzles can be used for CFD code validation.

  20. Aeroacoustic Improvements to Fluidic Chevron Nozzles

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda; Kinzie, Kevin; Whitmire, Julia; Abeysinghe, Amal

    2006-01-01

    Fluidic chevrons use injected air near the trailing edge of a nozzle to emulate mixing and jet noise reduction characteristics of mechanical chevrons. While previous investigations of "first generation" fluidic chevron nozzles showed only marginal improvements in effective perceived noise levels when compared to nozzles without injection, significant improvements in noise reduction characteristics were achieved through redesigned "second generation" nozzles on a bypass ratio 5 model system. The second-generation core nozzles had improved injection passage contours, external nozzle contour lines, and nozzle trailing edges. The new fluidic chevrons resulted in reduced overall sound pressure levels over that of the baseline nozzle for all observation angles. Injection ports with steep injection angles produced lower overall sound pressure levels than those produced by shallow injection angles. The reductions in overall sound pressure levels were the result of noise reductions at low frequencies. In contrast to the first-generation nozzles, only marginal increases in high frequency noise over that of the baseline nozzle were observed for the second-generation nozzles. The effective perceived noise levels of the new fluidic chevrons are shown to approach those of the core mechanical chevrons.

  1. Optimized profiles for incompressible flow metering nozzles

    NASA Astrophysics Data System (ADS)

    Lakshminarayanan, R.; Haji-Sheikh, A.; Lou, D. Y. S.; Spindler, M.

    1988-04-01

    The Euler-Lagrange equation was used to minimize shear stress in designing a flow-metering nozzle. The flow field in the nozzle was computed by solving the momentum equation in integral form. The profile of the nozzle was obtained by minimizing the shear losses in the converging section of the nozzle. Following computation of the profile, a metering nozzle was designed, constructed, and subsequently tested to evaluate the validity of the analysis. The nozzle was designed for a pipe diameter of 15.24 cm (6 in.) and a throat diameter of 9.266 cm (3.648 in.). The test results indicated a marked increase in the value of the discharge coefficient when it is compared with that for the ASME standard nozzle. The computed pressure distribution is in good agreement with the experimental data.

  2. Subsonic Euler Flows with Large Vorticity Through an Infinitely Long Axisymmetric Nozzle

    NASA Astrophysics Data System (ADS)

    Du, Lili; Duan, Ben

    2016-04-01

    This paper is a sequel to the earlier work Du and Duan (J Diff Equ 250:813-847, 2011) on well-posedness of steady subsonic Euler flows through infinitely long three-dimensional axisymmetric nozzles. In Du and Duan (J Diff Equ 250:813-847, 2011), the authors showed the existence and uniqueness of the global subsonic Euler flows through an infinitely long axisymmetric nozzle, when the variation of Bernoulli's function in the upstream is sufficiently small and the mass flux of the incoming flow is less than some critical value. The smallness of the variation of Bernoulli's function in the upstream prevents the attendance of the possible singularity in the nozzles, however, at the same time it also leads that the vorticity of the ideal flow is sufficiently small in the whole nozzle and the flows are indeed adjacent to axisymmetric potential flows. The purpose of this paper is to investigate the effects of the vorticity for the smooth subsonic ideal flows in infinitely long axisymmetric nozzles. We modify the formulation of the problem in the previous work Du and Duan (J Diff Equ 250:813-847, 2011) and the existence and uniqueness results on the smooth subsonic ideal polytropic flows in infinitely long axisymmetric nozzles without the restriction on the smallness of the vorticity are shown in this paper.

  3. Vibration damping for the Segmented Mirror Telescope

    NASA Astrophysics Data System (ADS)

    Maly, Joseph R.; Yingling, Adam J.; Griffin, Steven F.; Agrawal, Brij N.; Cobb, Richard G.; Chambers, Trevor S.

    2012-09-01

    The Segmented Mirror Telescope (SMT) at the Naval Postgraduate School (NPS) in Monterey is a next-generation deployable telescope, featuring a 3-meter 6-segment primary mirror and advanced wavefront sensing and correction capabilities. In its stowed configuration, the SMT primary mirror segments collapse into a small volume; once on location, these segments open to the full 3-meter diameter. The segments must be very accurately aligned after deployment and the segment surfaces are actively controlled using numerous small, embedded actuators. The SMT employs a passive damping system to complement the actuators and mitigate the effects of low-frequency (<40 Hz) vibration modes of the primary mirror segments. Each of the six segments has three or more modes in this bandwidth, and resonant vibration excited by acoustics or small disturbances on the structure can result in phase mismatches between adjacent segments thereby degrading image quality. The damping system consists of two tuned mass dampers (TMDs) for each of the mirror segments. An adjustable TMD with passive magnetic damping was selected to minimize sensitivity to changes in temperature; both frequency and damping characteristics can be tuned for optimal vibration mitigation. Modal testing was performed with a laser vibrometry system to characterize the SMT segments with and without the TMDs. Objectives of this test were to determine operating deflection shapes of the mirror and to quantify segment edge displacements; relative alignment of λ/4 or better was desired. The TMDs attenuated the vibration amplitudes by 80% and reduced adjacent segment phase mismatches to acceptable levels.

  4. Modifications to the nozzle test chamber to extend nozzle static-test capability

    NASA Technical Reports Server (NTRS)

    Keyes, J. W.

    1985-01-01

    The nozzle test chamber was modified to provide a high-pressure-ratio nozzle static-test capability. Experiments were conducted to determine the range of the ratio of nozzle total pressure to chamber pressure and to make direct nozzle thrust measurements using a three-component strain-gage force balance. Pressure ratios from 3 to 285 were measured with several axisymmetric nozzles at a nozzle total pressure of 15 to 190 psia. Devices for measuring system mass flow were calibrated using standard axisymmetric convergent choked nozzles. System mass-flow rates up to 10 lbm/sec are measured. The measured thrust results of these nozzles are in good agreement with one-dimensional theoretical predictions for convergent nozzles.

  5. Single expansion ramp nozzle simulations

    NASA Technical Reports Server (NTRS)

    Ruffin, Stephen M.; Venkatapathy, Ethiraj; Lee, Seung-Ho; Keener, Earl R.; Spaid, Frank W.

    1992-01-01

    The single-expansion-ramp-nozzle (SERN) experiment underway at NASA Ames Research Center simulates the National Aerospace Plane propulsive jet-plume flow. Recently, limited experimental data has become available from an experiment with a generic nozzle/afterbody model in a hypersonic wind tunnel. The present paper presents full three-dimensional solutions obtained with the implicit Navier-Stokes solver, FL3D, for the baseline model and a version of the model with side extensions. Analysis of the computed flow clearly shows the complex 3-D nature of the flow, critical flow features, and the effect of side extensions on the plume flow development. Flow schematics appropriate for the conditions tested are presented for the baseline model and the model with side extensions. The computed results show excellent agreement with experimental shadowgraph and with surface pressure measurements. The computed and experimental surface oil-flows show the same features but may be improved by appropriate turbulence modeling.

  6. Spray nozzle for fire control

    NASA Astrophysics Data System (ADS)

    Papavergos, Panayiotis G.

    1990-09-01

    The design of a spray nozzle for fire control is described. It produces a spray of gas and liquid having an oval transverse cross section and it comprises a mixing chamber with an oval transverse cross section adapted to induce a toroidal mixing pattern in pressurized gas and liquid introduced to the mixing chamber through a plurality of inlets. In a preferred embodiment the mixing chamber is toroidal. The spray nozzle produces an oval spray pattern for more efficient wetting of narrow passages and is suitable for fire control systems in vehicles or other confined spaces. Vehicles to which this invention may be applied include trains, armoured vehicles, ships, hovercraft, submarines, oil rigs, and most preferably, aircraft.

  7. Fluid flow nozzle energy harvesters

    NASA Astrophysics Data System (ADS)

    Sherrit, Stewart; Lee, Hyeong Jae; Walkemeyer, Phillip; Winn, Tyler; Tosi, Luis Phillipe; Colonius, Tim

    2015-04-01

    Power generation schemes that could be used downhole in an oil well to produce about 1 Watt average power with long-life (decades) are actively being developed. A variety of proposed energy harvesting schemes could be used to extract energy from this environment but each of these has their own limitations that limit their practical use. Since vibrating piezoelectric structures are solid state and can be driven below their fatigue limit, harvesters based on these structures are capable of operating for very long lifetimes (decades); thereby, possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. An initial survey [1] identified that spline nozzle configurations can be used to excite a vibrating piezoelectric structure in such a way as to convert the abundant flow energy into useful amounts of electrical power. This paper presents current flow energy harvesting designs and experimental results of specific spline nozzle/ bimorph design configurations which have generated suitable power per nozzle at or above well production analogous flow rates. Theoretical models for non-dimensional analysis and constitutive electromechanical model are also presented in this paper to optimize the flow harvesting system.

  8. Small drops from large nozzles

    NASA Astrophysics Data System (ADS)

    Castrejon-Pita, Alfonso Arturo; Said Mohamed, Ahmed; Castrejon-Pita, Jose Rafael; Herrada, Miguel Angel

    2015-11-01

    We report experimental and numerical results of the generation of drops which are significantly smaller than the nozzle from which they are generated. The system consists of a cylindrical reservoir and two endplates. One plate is a thin metal sheet with a small orifice in its centre which acts as the nozzle. The other end consists of a piston which moves by the action of an elecromechanical actuator which in turn is driven by sine-shape pull-mode pulses. The meniscus (formed at the nozzle) is thus first overturned, forming a cavity. This cavity collapses and a thin and fast jet emerges from its centre. Under appropriate conditions the tip of this jet breaks up and produces a single diminutive drop. A good agreement between the experimental and numerical results was found. Also, a series of experiments were performed in order to study the effects that the pulse amplitude and width, together with variations in the liquid properties, have over the final size of the droplet. Based on these experiments, a predictive law for the droplet size has been derived. This work was funded by the Royal Society (University Research Fellowship and Research Grant), the John Fell Fund (Oxford University Press), the Ministry of Science and Education (DPI2013-46485 Spain), and the Junta de Andalucia (P08-TEP-31704128 Spain).

  9. Noise measurements from an ejector suppressor nozzle in the NASA Lewis 9- by 15-foot low speed wind tunnel

    NASA Technical Reports Server (NTRS)

    Krejsa, Eugene A.; Cooper, Beth A.; Hall, David G.; Khavaran, Abbas

    1990-01-01

    Acoustic results are presented of a cooperative nozzle test program between NASA and Pratt and Whitney, conducted in the NASA-Lewis 9 x 15 ft Anechoic Wind Tunnel. The nozzle tested was the P and W Hypermix Nozzle concept, a 2-D lobed mixer nozzle followed by a short ejector section made to promote rapid mixing of the induced ejector nozzle flow. Acoustic and aerodynamic measurements were made to determine the amount of ejector pumping, degree of mixing, and noise reduction achieved. A series of tests were run to verify the acoustic quality of this tunnel. The results indicated that the tunnel test section is reasonably anechoic but that background noise can limit the amount of suppression observed from suppressor nozzles. Also, a possible internal noise was observed in the air supply system. The P and W ejector suppressor nozzle demonstrated the potential of this concept to significantly reduce jet noise. Significant reduction in low frequency noise was achieved by increasing the peak jet noise frequency. This was accomplished by breaking the jet into segments with smaller dimensions than those of the baseline nozzle. Variations in ejector parameters had little effect on the noise for the geometries and the range of temperatures and pressure ratios tested.

  10. Nozzle Aerodynamic Stability During a Throat Shift

    NASA Technical Reports Server (NTRS)

    Kawecki, Edwin J.; Ribeiro, Gregg L.

    2005-01-01

    An experimental investigation was conducted on the internal aerodynamic stability of a family of two-dimensional (2-D) High Speed Civil Transport (HSCT) nozzle concepts. These nozzles function during takeoff as mixer-ejectors to meet acoustic requirements, and then convert to conventional high-performance convergent-divergent (CD) nozzles at cruise. The transition between takeoff mode and cruise mode results in the aerodynamic throat and the minimum cross-sectional area that controls the engine backpressure shifting location within the nozzle. The stability and steadiness of the nozzle aerodynamics during this so called throat shift process can directly affect the engine aerodynamic stability, and the mechanical design of the nozzle. The objective of the study was to determine if pressure spikes or other perturbations occurred during the throat shift process and, if so, identify the caused mechanisms for the perturbations. The two nozzle concepts modeled in the test program were the fixed chute (FC) and downstream mixer (DSM). These 2-D nozzles differ principally in that the FC has a large over-area between the forward throat and aft throat locations, while the DSM has an over-area of only about 10 percent. The conclusions were that engine mass flow and backpressure can be held constant simultaneously during nozzle throat shifts on this class of nozzles, and mode shifts can be accomplished at a constant mass flow and engine backpressure without upstream pressure perturbations.

  11. Frozen Chemistry Effects on Nozzle Performance Simulations

    NASA Technical Reports Server (NTRS)

    Yoder, Dennis A.; Georgiadis, Nicholas J.; O'Gara, Michael R.

    2009-01-01

    Simulations of exhaust nozzle flows are typically conducted assuming the gas is calorically perfect, and typically modeled as air. However the gas inside a real nozzle is generally composed of combustion products whose thermodynamic properties may differ. In this study, the effect of gas model assumption on exhaust nozzle simulations is examined. The three methods considered model the nozzle exhaust gas as calorically perfect air, a calorically perfect exhaust gas mixture, and a frozen exhaust gas mixture. In the latter case the individual non-reacting species are tracked and modeled as a gas which is only thermally perfect. Performance parameters such as mass flow rate, gross thrust, and thrust coefficient are compared as are mean flow and turbulence profiles in the jet plume region. Nozzles which operate at low temperatures or have low subsonic exit Mach numbers experience relatively minor temperature variations inside the nozzle, and may be modeled as a calorically perfect gas. In those which operate at the opposite extreme conditions, variations in the thermodynamic properties can lead to different expansion behavior within the nozzle. Modeling these cases as a perfect exhaust gas flow rather than air captures much of the flow features of the frozen chemistry simulations. Use of the exhaust gas reduces the nozzle mass flow rate, but has little effect on the gross thrust. When reporting nozzle thrust coefficient results, however, it is important to use the appropriate gas model assumptions to compute the ideal exit velocity. Otherwise the values obtained may be an overly optimistic estimate of nozzle performance.

  12. Residual stresses in weld deposited clad pressure vessels and nozzles

    SciTech Connect

    Jones, D.P.; Mabe, W.R.; Shadley, J.R.; Rybicki, E.F.

    1998-04-01

    Results of through-thickness residual stress measurements are provided for a variety of samples of weld deposited 308/309L stainless steel and Alloy 600 cladding on low-alloy pressure vessel ferritic steels. Clad thicknesses between 5 and 9mm on samples that vary in thickness from 45 to 200mm were studied. The samples were taken from flat plates, from a spherical head of a pressure vessel, from a ring-segment of a nozzle bore, and from the transition radius between a nozzle and a pressure vessel shell. A layer removal method was used to measure the residual stresses. The effects of uncertainties in elastic constants (Young`s modulus and Poisson`s ratio) as well as experimental error are assessed. All measurements were done at room temperature. The results of this work indicate that curvature plays a significant role in cladding residual stress and that tensile residual stresses as high as the yield stress can be measured in the cladding material. Since the vessel from which the spherical and nozzle corner samples were taken was hydrotested, and the flat plate specimens were taken from specimens used in mechanical fatigue testing, these results suggest that rather high tensile residual stresses can be retained in the cladding material even after some mechanical loading associated with hydrotesting and that higher levels of hydrotest loading would be required to alter the cladding residual stresses.

  13. Segmental neurofibromatosis.

    PubMed

    Galhotra, Virat; Sheikh, Soheyl; Jindal, Sanjeev; Singla, Anshu

    2014-07-01

    Segmental neurofibromatosis is a rare disorder, characterized by neurofibromas or cafι-au-lait macules limited to one region of the body. Its occurrence on the face is extremely rare and only few cases of segmental neurofibromatosis over the face have been described so far. We present a case of segmental neurofibromatosis involving the buccal mucosa, tongue, cheek, ear, and neck on the right side of the face. PMID:25565748

  14. Experimental evaluation of expendable supersonic nozzle concepts

    NASA Technical Reports Server (NTRS)

    Baker, V.; Kwon, O.; Vittal, B.; Berrier, B.; Re, R.

    1990-01-01

    Exhaust nozzles for expendable supersonic turbojet engine missile propulsion systems are required to be simple, short and compact, in addition to having good broad-range thrust-minus-drag performance. A series of convergent-divergent nozzle scale model configurations were designed and wind tunnel tested for a wide range of free stream Mach numbers and nozzle pressure ratios. The models included fixed geometry and simple variable exit area concepts. The experimental and analytical results show that the fixed geometry configurations tested have inferior off-design thrust-minus-drag performance in the transonic Mach range. A simple variable exit area configuration called the Axi-Quad nozzle, combining features of both axisymmetric and two-dimensional convergent-divergent nozzles, performed well over a broad range of operating conditions. Analytical predictions of the flow pattern as well as overall performance of the nozzles, using a fully viscous, compressible CFD code, compared very well with the test data.

  15. Strain gauge ambiguity sensor for segmented mirror active optical system

    NASA Technical Reports Server (NTRS)

    Wyman, C. L.; Howe, T. L. (Inventor)

    1974-01-01

    A system is described to measure alignment between interfacing edges of mirror segments positioned to form a segmented mirror surface. It serves as a gauge having a bending beam with four piezoresistive elements coupled across the interfaces of the edges of adjacent mirror segments. The bending beam has a first position corresponding to alignment of the edges of adjacent mirror segments, and it is bendable from the first position in a direction and to a degree dependent upon the relative misalignment between the edges of adjacent mirror segments to correspondingly vary the resistance of the strain guage. A source of power and an amplifier are connected in circuit with the strain gauge whereby the output of the amplifier varies according to the misalignment of the edges of adjacent mirror segments.

  16. LTA measurements on shuttle cleaning nozzle

    NASA Technical Reports Server (NTRS)

    1995-01-01

    A laser transit anemometer was used to make flow field velocity measurements on a supersonic air/water cleaning nozzle used to clean liquid oxygen shuttle components at Kennedy Space Center. The velocity along the centerline of the nozzle was characterized by the LTA system and compared with CFD calculations to ascertain the optimum distance the nozzle should be placed from the liquid oxygen part for maximum cleaning..

  17. Wire Whip Keeps Spray Nozzle Clean

    NASA Technical Reports Server (NTRS)

    Carroll, H. R.

    1982-01-01

    Air-turbine-driven wire whip is clamped near spray-gun mount. When spray gun is installed, wire whip is in position to remove foam buildup from nozzle face. Two lengths of wire 1 to 2 inches long and about 0.03 inch in thickness are used. Foam spray would be prevented from accumulating on nozzle face by increasing purge flow and cutting vortex-generating grooves inside cap and on nozzle flats.

  18. Insert metering plates for gas turbine nozzles

    DOEpatents

    Burdgick, Steven S.; Itzel, Gary; Chopra, Sanjay; Abuaf, Nesim; Correia, Victor H.

    2004-05-11

    The invention comprises a metering plate which is assembled to an impingement insert for use in the nozzle of a gas turbine. The metering plate can have one or more metering holes and is used to balance the cooling flow within the nozzle. A metering plate with multiple holes reduces static pressure variations which result from the cooling airflow through the metering plate. The metering plate can be assembled to the insert before or after the insert is inserted into the nozzle.

  19. Welded nozzle extension for Ariane launch vehicles

    NASA Astrophysics Data System (ADS)

    Wolf, D. B.; Nicolay, R. C.

    The most prominent feature of the nozzle extension conponent of Ariane launch vehicle Vulcan engines is the welding together of numerous spirally arranged rectangular tubes with constant cross section. Accounts are presently given of these nozzles' fabrication method and the results of destructive and NDE investigations of these gas-shielded tungsten-arc weldments. Attention is given to the character and consequences of geometric irregularities imparted by the welding process and to the complexity of the nozzle inlet and outlet manifolds.

  20. Supersonic jets from bevelled rectangular nozzles

    NASA Technical Reports Server (NTRS)

    Rice, Edward J.; Raman, Ganesh

    1993-01-01

    The influence of nozzle exit geometry on jet mixing and noise production was studied experimentally for a series of rectangular nozzles operating at supersonic jet velocities. Both converging (C) and converging-diverging (C-D) nozzles were built with asymmetrical (single bevel) and symmetrical (double bevel) exit chambers and with conventional straight exits for comparison. About a four decibel reduction of peak mixing noise was observed for the double bevelled C-D nozzle operated at design pressure ratio. All bevelled geometries provided screech noise reduction for under-expanded jets and an upstream mixing noise directivity shift which would be beneficial for improved acoustic treatment performance of a shrouded system.

  1. Experimental study of low Reynolds number nozzles

    NASA Technical Reports Server (NTRS)

    Grisnik, Stanley P.; Smith, Tamara A.; Saltz, Larry E.

    1987-01-01

    High-performance electrothermal thrusters operate in a low nozzle-throat Reynolds number regime. Under these conditions, the flow boundary layer occupies a large volume inside the nozzle, contributing to large viscous losses. Four nozzles (conical, bell, trumpet, and modified trumpet) and a sharp-edged orifice were evaluated over a Reynolds number range of 500 to 9000 with unheated nitrogen and hydrogen. The nozzles showed significant decreases in specific impulse efficiency with decreasing Reynolds number. At Reynolds numbers less than 1000, all four nozzles were probably filled with a large boundary layer. The discharge coefficient decreased with Reynolds number in the same manner as the specific impulse efficiency. The bell and modified trumpet nozzles had discharge coefficients 4 to 8 percent higher than those of the cone or trumpet nozzles. The Two-Dimensional Kinetics (TDK) nozzle analysis computer program was used to predict nozzle performance. The results were then compared to the experimental results in order to determine the accuracy of the program within this flow regime.

  2. NPAC-Nozzle Performance Analysis Code

    NASA Technical Reports Server (NTRS)

    Barnhart, Paul J.

    1997-01-01

    A simple and accurate nozzle performance analysis methodology has been developed. The geometry modeling requirements are minimal and very flexible, thus allowing rapid design evaluations. The solution techniques accurately couple: continuity, momentum, energy, state, and other relations which permit fast and accurate calculations of nozzle gross thrust. The control volume and internal flow analyses are capable of accounting for the effects of: over/under expansion, flow divergence, wall friction, heat transfer, and mass addition/loss across surfaces. The results from the nozzle performance methodology are shown to be in excellent agreement with experimental data for a variety of nozzle designs over a range of operating conditions.

  3. Crossflow in two-dimensional asymmetric nozzles

    NASA Technical Reports Server (NTRS)

    Sebacher, D. I.; Lee, L. P.

    1975-01-01

    An experimental investigation of the crossflow effects in three contoured, two-dimensional asymmetric nozzles is described. The data were compared with theoretical predictions of nozzle flow by using an inviscid method of characteristics solution and two-dimensional turbulent boundary-layer calculations. The effect of crossflow as a function of the nozzle maximum expansion angle was studied by use of oil-flow techniques, static wall-pressure measurements, and impact-pressure surveys at the nozzle exit. Reynolds number effects on crossflow were investigated.

  4. Turbulence Measurements of Rectangular Nozzles with Bevel

    NASA Technical Reports Server (NTRS)

    Bridges, James; Wernet, Mark P.

    2015-01-01

    This paper covers particle image velocimetry measurements of a family of rectangular nozzles with aspect ratios 2, 4, and 8, in the high subsonic flow regime. Far-field acoustic results, presented previously, showed that increasing aspect ratios increased the high frequency noise, especially directed in the polar plane containing the minor axis of the nozzle. The measurements presented here have important implications in the modeling of turbulent sources for acoustic analogy theories. While the nonaxisymmetric mean flow from the rectangular nozzles can be studied reliably using computational solutions, the nonaxisymmetry of the turbulent fluctuations, particularly at the level of velocity components, cannot; only measurements such as these can determine the impact of nozzle geometry on acoustic source anisotropy. Additional nozzles were constructed that extended the wide lip on one side of these nozzles to form beveled nozzles. The paper first documents the velocity fields, mean and variance, from the round, rectangular, and beveled rectangular nozzles at high subsonic speeds. A second section introduces measures of the isotropy of the turbulence, such as component ratios and lengthscales, first by showing them for a round jet and then for the rectangular nozzles. From these measures the source models of acoustic analogy codes can be judged or modified to account for these anisotropies.

  5. Segmental neurofibromatosis.

    PubMed

    Toy, Brian

    2003-10-01

    Segmental neurofibromatosis is a rare variant of neurofibromatosis in which skin lesions are confined to a circumscribed body segment. A case of a 72-year-old woman with this condition is presented. Clinical features and genetic evidence are reviewed. PMID:14594599

  6. Active Segmentation

    PubMed Central

    Mishra, Ajay; Aloimonos, Yiannis

    2009-01-01

    The human visual system observes and understands a scene/image by making a series of fixations. Every fixation point lies inside a particular region of arbitrary shape and size in the scene which can either be an object or just a part of it. We define as a basic segmentation problem the task of segmenting that region containing the fixation point. Segmenting the region containing the fixation is equivalent to finding the enclosing contour- a connected set of boundary edge fragments in the edge map of the scene - around the fixation. This enclosing contour should be a depth boundary. We present here a novel algorithm that finds this bounding contour and achieves the segmentation of one object, given the fixation. The proposed segmentation framework combines monocular cues (color/intensity/texture) with stereo and/or motion, in a cue independent manner. The semantic robots of the immediate future will be able to use this algorithm to automatically find objects in any environment. The capability of automatically segmenting objects in their visual field can bring the visual processing to the next level. Our approach is different from current approaches. While existing work attempts to segment the whole scene at once into many areas, we segment only one image region, specifically the one containing the fixation point. Experiments with real imagery collected by our active robot and from the known databases 1 demonstrate the promise of the approach. PMID:20686671

  7. Improvement in Recursive Hierarchical Segmentation of Data

    NASA Technical Reports Server (NTRS)

    Tilton, James C.

    2006-01-01

    A further modification has been made in the algorithm and implementing software reported in Modified Recursive Hierarchical Segmentation of Data (GSC- 14681-1), NASA Tech Briefs, Vol. 30, No. 6 (June 2006), page 51. That software performs recursive hierarchical segmentation of data having spatial characteristics (e.g., spectral-image data). The output of a prior version of the software contained artifacts, including spurious segmentation-image regions bounded by processing-window edges. The modification for suppressing the artifacts, mentioned in the cited article, was addition of a subroutine that analyzes data in the vicinities of seams to find pairs of regions that tend to lie adjacent to each other on opposite sides of the seams. Within each such pair, pixels in one region that are more similar to pixels in the other region are reassigned to the other region. The present modification provides for a parameter ranging from 0 to 1 for controlling the relative priority of merges between spatially adjacent and spatially non-adjacent regions. At 1, spatially-adjacent-/spatially- non-adjacent-region merges have equal priority. At 0, only spatially-adjacent-region merges (no spectral clustering) are allowed. Between 0 and 1, spatially-adjacent- region merges have priority over spatially- non-adjacent ones.

  8. Tier-Adjacency Is Not a Necessary Condition for Learning Phonotactic Dependencies

    ERIC Educational Resources Information Center

    Koo, Hahn; Callahan, Lydia

    2012-01-01

    One hypothesis raised by Newport and Aslin to explain how speakers learn dependencies between nonadjacent phonemes is that speakers track bigram probabilities between two segments that are adjacent to each other within a tier of their own. The hypothesis predicts that a dependency between segments separated from each other at the tier level cannot…

  9. Making Nozzles From Hard Materials

    NASA Technical Reports Server (NTRS)

    Wells, Dennis L.

    1989-01-01

    Proposed method of electrical-discharge machining (EDM) cuts hard materials like silicon carbide into smoothly contoured parts. Concept developed for fabrication of interior and exterior surfaces and internal cooling channels of convergent/divergent nozzles. EDM wire at skew angle theta creates hyperboloidal cavity in tube. Wire offset from axis of tube and from axis of rotation by distance equal to throat radius. Maintaining same skew angle as that used to cut hyperboloidal inner surface but using larger offset, cooling channel cut in material near inner hyperboloidal surface.

  10. Nozzle flow with vibrational nonequilibrium

    NASA Technical Reports Server (NTRS)

    Heinbockel, J. H.; Landry, J. G.

    1995-01-01

    This research concerns the modeling and numerical solutions of the coupled system of compressible Navier-Stokes equations in cylindrical coordinates under conditions of equilibrium and nonequilibrium thermodynamics. The problem considered was the modeling of a high temperature diatomic gas N2 flowing through a converging-diverging high expansion nozzle. The problem was modeled in two ways. The first model uses a single temperature with variable specific heats as functions of this temperature. For the second model we assume that the various degrees of freedom all have a Boltzmann distribution and that there is a continuous redistribution of energy among the various degrees of freedom as the gas passes through the nozzle. Each degree of freedom is assumed to have its own temperature and, consequently, each system state can be characterized by these temperatures. This suggests that formulation of a second model with a vibrational degree of freedom along with a rotational-translation degree of freedom, each degree of freedom having its own temperature. Initially the vibrational degree of freedom is excited by heating the gas to a high temperature. As the high temperature gas passes through the nozzle throat there is a sudden drop in temperature along with a relaxation time for the vibrational degree of freedom to achieve equilibrium with the rotational-translation degree of freedom. That is, we assume that the temperature change upon passing through the throat is so great that the changes in the vibrational degree of freedom occur at a much slower pace and consequently lags behind the rotational-translational energy changes. This lag results in a finite relaxation time. In this context the term nonequilibrium is used to denote the fact that the energy content of the various degrees of freedom are characterized by two temperatures. We neglect any chemical reactions which could also add nonequilibrium effects. We develop the energy equations for the nonequilibrium model

  11. Fuel nozzle assembly for use in turbine engines and methods of assembling same

    DOEpatents

    Uhm, Jong Ho; Johnson, Thomas Edward

    2015-02-03

    A fuel nozzle for use with a turbine engine is described herein. The fuel nozzle includes a housing that is coupled to a combustor liner defining a combustion chamber. The housing includes an endwall that at least partially defines the combustion chamber. A plurality of mixing tubes extends through the housing for channeling fuel to the combustion chamber. Each mixing tube of the plurality of mixing tubes includes an inner surface that extends between an inlet portion and an outlet portion. The outlet portion is oriented adjacent the housing endwall. At least one of the plurality of mixing tubes includes a plurality of projections that extend outwardly from the outlet portion. Adjacent projections are spaced a circumferential distance apart such that a groove is defined between each pair of circumferentially-apart projections to facilitate enhanced mixing of fuel in the combustion chamber.

  12. Nozzle

    DOEpatents

    Chen, Alexander G.; Fotache, Catalin G.

    2008-04-01

    The fuel injector has a first means defining a number of flowpaths each having an inlet for receiving air and an outlet for discharging a fuel/air mixture. One or more arrays of vanes are each positioned to impart swirl to an associated one or more of the flowpaths. Second means are provided for introducing the fuel to the air.

  13. Apparatus For Laminating Segmented Core For Electric Machine

    DOEpatents

    Lawrence, Robert Anthony; Stabel, Gerald R

    2003-06-17

    A segmented core for an electric machine includes segments stamped from coated electric steel. The segments each have a first end, a second end, and winding openings. A predetermined number of segments are placed end-to-end to form layers. The layers are stacked such that each of the layers is staggered from adjacent layers by a predetermined rotation angle. The winding openings of each of the layers are in vertical alignment with the winding openings of the adjacent layers. The stack of layers is secured to form the segmented core.

  14. Nozzle extension design status report

    NASA Technical Reports Server (NTRS)

    Classen, L. B.

    1972-01-01

    Twenty possible concepts of a possible nozzle/nozzle extension interface were originated. Not all of the concepts were considered worthy of analysis time. Six of them were thermally analyzed and three were stress analyzed. These analyses were done to determine which of the concepts would have the best chance of succeeding, that is, they were a screening process which was to allow rating of one concept against another. This was done because adequate material properties to determine absolute stress levels were not available at the time of the analyses. Through all of the concepts still exhibit some areas of negative margin of safety, concept no. 1 shows good promise that, with slight modifications, it could have all positive margins of safety. Another significant question, regarding these designs, has to do with the Grafoil seals and insulators. Some additional data was just recently received on Grafoil properties, but it was too late to incorporate in the analyses. The new data were not significantly different from the properties which were used.

  15. The 'whistler-nozzle' phenomenon

    NASA Technical Reports Server (NTRS)

    Hussain, A. K. M. F.; Hasan, M. A. Z.

    1983-01-01

    The whistler nozzle is a simple device which can induce jet self-excitations of controllable amplitudes and frequencies and appears highly promising for many applications involving turbulent transport, combustion and aerodynamic noise. The characteristics of this curious phenomenon are documented for different values of the controlling parameters and attempts to explain the phenomenon. It is shown that the whistler excitation results from the coupling of two independent resonance mechanisms: shear-layer tone resulting from the impingement of the pipe-exit shear layer on the collar lip, and organ-pipe resonance of the pipe-nozzle. The crucial role of the shear-layer tone in driving the organ-pipe resonance is proven by reproducing the event in pipe-ring and pipe-hole configurations in the absence of the collar. It is also shown that this phenomenon is the strongest when the self-excitation frequency matches the preferred mode of the jet. Previously announced in STAR as N83-20706

  16. Method and apparatus for setting precise nozzle/belt and nozzle/edge dam block gaps

    DOEpatents

    Carmichael, Robert J.; Dykes, Charles D.; Woodrow, Ronald

    1989-05-16

    A pair of guide pins are mounted on sideplate extensions of the caster and mating roller pairs are mounted on the nozzle assembly. The nozzle is advanced toward the caster so that the roller pairs engage the guide pins. Both guide pins are remotely adjustable in the vertical direction by hydraulic cylinders acting through eccentrics. This moves the nozzle vertically. The guide pin on the inboard side of the caster is similarly horizontally adjustable. The nozzle roller pair which engage the inboard guide pin are flanged so that the nozzle moves horizontally with the inboard guide pin.

  17. Performance and durability of improved air-atomizing splash-cone fuel nozzles

    NASA Technical Reports Server (NTRS)

    Ingebo, R. D.; Norgren, C. T.

    1974-01-01

    An improved design of air-atomizing fuel nozzles was determined from a study of four differently shaped splash-cone fuel nozzles after 56 hr of durability testing in a combustor segment. Test conditions included fuel-air ratios of 0.008 to 0.018, inlet-air total pressures of 41 to 203 N/cm, inlet-air temperatures of 477 to 811 K, and a reference velocity of 21.3 m/sec. Flat-tip fuel nozzles showed the least erosion damage and at a combustor operating condition of 700 K and 101 N/sq cm an oxides-of-nitrogen emission index of 12 and a smoke number of approximately 18 with a fuel-air ratio of 0.018. Emission indices for carbon monoxide and unburned hydrocarbons were 44 and 16, respectively, at simulated idle conditions of 477 K and 41 N/sq cm.

  18. Nitrous oxide cooling in hybrid rocket nozzles

    NASA Astrophysics Data System (ADS)

    Lemieux, Patrick

    2010-02-01

    The Department of Mechanical Engineering at the California Polytechnic State University, San Luis Obispo, has developed an innovative program of experimental research and development on hybrid rocket motors (where the fuel and the oxidizer are in different phases prior to combustion). One project currently underway involves the development of aerospike nozzles for such motors. These nozzles, however, are even more susceptible to throat ablation than regular converging-diverging nozzles, due the nature of their flow expansion mechanism. This paper presents the result of a recent development project focused on reducing throat ablation in hybrid rocket motor nozzles. Although the method is specifically targeted at increasing the life and operating range of aerospike nozzles, this paper describes its proof-of-concept implementation on conventional nozzles. The method is based on a regenerative cooling mechanism that differs in practice from that used in liquid propellant motors. A series of experimental tests demonstrate that this new method is not only effective at reducing damage in the most ablative region of the nozzle, but that the nozzle can survive multiple test runs.

  19. Erosion-Resistant Water-Blast Nozzle

    NASA Technical Reports Server (NTRS)

    Roberts, Marion L.; Rice, R. M.; Cosby, S. A.

    1988-01-01

    Design of nozzle reduces erosion of orifice by turbulent high-pressure water flowing through it. Improved performance and resistance to erosion achieved by giving interior nozzle surface long, gradual convergence before exit orifice abrupt divergence after orifice and by machining surface to smooth finish.

  20. Exhaust Nozzle Plume Effects on Sonic Boom Test Results for Isolated Nozzles

    NASA Technical Reports Server (NTRS)

    Castner, Raymond S.

    2011-01-01

    Reducing or eliminating the operational restrictions of supersonic aircraft over populated areas has led to extensive research at NASA. Restrictions were due to the disturbance of the sonic boom, caused by the coalescence of shock waves formed off the aircraft. Recent work has been performed to reduce the magnitude of the sonic boom N-wave generated by airplane components with focus on shock waves caused by the exhaust nozzle plume. Previous Computational Fluid Dynamics (CFD) analysis showed how the shock wave formed at the nozzle lip interacts with the nozzle boat-tail expansion wave. An experiment was conducted in the 1- by 1-ft Supersonic Wind Tunnel at the NASA Glenn Research Center to validate the computational study. Results demonstrated how the nozzle lip shock moved with increasing nozzle pressure ratio (NPR) and reduced the nozzle boat-tail expansion, causing a favorable change in the observed pressure signature. Experimental results were presented for comparison to the CFD results. The strong nozzle lip shock at high values of NPR intersected the nozzle boat-tail expansion and suppressed the expansion wave. Based on these results, it may be feasible to reduce the boat-tail expansion for a future supersonic aircraft with under-expanded nozzle exhaust flow by modifying nozzle pressure or nozzle divergent section geometry.

  1. Thermal Analysis of Compressible CO2 Flow for PFE TeSS Nozzle of Fire Detection System

    NASA Technical Reports Server (NTRS)

    Zhang, Y. Michael; Lee, Wen-Chin; Keener, John F.; Smith, F. D.

    2002-01-01

    A thermal analysis of the compressible CO2 flow for the Portable Fire Extinguisher (PFE) system has been performed. A SINDA/FLUINT model has been developed for this analysis. The model includes the PFE tank and the TeSS nozzle, and both have initial temperature of 72 F. In order to investigate the thermal effect on the nozzle due to discharging CO2, the PFE TeSS nozzle pipe has been divided into three segments. This model also includes heat transfer predictions for PFE tank inner and outer wall surfaces. The simulation results show that the CO2 discharge rates have fulfilled the minimum flow requirements that the PFE system discharges 3.0 Ibm CO2 in 10 seconds and 5.5 Ibm of CO2 in 45 seconds during its operation. At 45 seconds, the PFE tank wall temperature is 63 F, and the TeSS nozzle cover wall temperatures for the three segments are 47 F, 53 F and 37 F, respectively. Thermal insulation for personal protection is used for the first two segments of the TeSS nozzle. The simulation results also indicate that at 50 seconds, the remaining CO2 in the tank may be near the triple point (gas, liquid and solid) state and, therefore, restricts the flow.

  2. Comparative investigation of multiplane thrust vectoring nozzles

    NASA Technical Reports Server (NTRS)

    Capone, F.; Smereczniak, P.; Spetnagel, D.; Thayer, E.

    1992-01-01

    The inflight aerodynamic performance of multiplane vectoring nozzles is critical to development of advanced aircraft and flight control systems utilizing thrust vectoring. To investigate vectoring nozzle performance, subscale models of two second-generation thrust vectoring nozzle concepts currently under development for advanced fighters were integrated into an axisymmetric test pod. Installed drag and vectoring performance characteristics of both concepts were experimentally determined in wind tunnel testing. CFD analyses were conducted to understand the impact of internal flow turning on thrust vectoring characteristics. Both nozzles exhibited drag comparable with current nonvectoring axisymmetric nozzles. During vectored-thrust operations, forces produced by external flow effects amounted to about 25 percent of the total force measured.

  3. Exhaust Nozzle Plume and Shock Wave Interaction

    NASA Technical Reports Server (NTRS)

    Castner, Raymond S.; Elmiligui, Alaa; Cliff, Susan

    2013-01-01

    Fundamental research for sonic boom reduction is needed to quantify the interaction of shock waves generated from the aircraft wing or tail surfaces with the exhaust plume. Both the nozzle exhaust plume shape and the tail shock shape may be affected by an interaction that may alter the vehicle sonic boom signature. The plume and shock interaction was studied using Computational Fluid Dynamics simulation on two types of convergent-divergent nozzles and a simple wedge shock generator. The nozzle plume effects on the lower wedge compression region are evaluated for two- and three-dimensional nozzle plumes. Results show that the compression from the wedge deflects the nozzle plume and shocks form on the deflected lower plume boundary. The sonic boom pressure signature of the wedge is modified by the presence of the plume, and the computational predictions show significant (8 to 15 percent) changes in shock amplitude.

  4. Unconventional nozzle tradeoff study. [space tug propulsion

    NASA Technical Reports Server (NTRS)

    Obrien, C. J.

    1979-01-01

    Plug cluster engine design, performance, weight, envelope, operational characteristics, development cost, and payload capability, were evaluated and comparisons were made with other space tug engine candidates using oxygen/hydrogen propellants. Parametric performance data were generated for existing developed or high technology thrust chambers clustered around a plug nozzle of very large diameter. The uncertainties in the performance prediction of plug cluster engines with large gaps between the modules (thrust chambers) were evaluated. The major uncertainty involves, the aerodynamics of the flow from discrete nozzles, and the lack of this flow to achieve the pressure ratio corresponding to the defined area ratio for a plug cluster. This uncertainty was reduced through a cluster design that consists of a plug contour that is formed from the cluster of high area ratio bell nozzles that have been scarfed. Light-weight, high area ratio, bell nozzles were achieved through the use of AGCarb (carbon-carbon cloth) nozzle extensions.

  5. Jet noise modification by the 'whistler nozzle'

    NASA Technical Reports Server (NTRS)

    Hasan, M. A. Z.; Islam, O.; Hussain, A. K. M. F.

    1984-01-01

    The farfield noise characteristics of a subsonic whistler nozzle jet are measured as a function of Mach number (0.25, 0.37, and, 0.51), emission angle, and excitation mode. It is shown that a whistler nozzle has greater total and broadband acoustic power than an excited contraction nozzle; and that the intensity of far-field noise is a function of emission angle, Mach number, and whistler excitation stage. The whistler nozzle excitation produces broadband noise amplification with constant spectral shape; the broadband noise amplification (without associated whistler tones and harmonics) increases omnidirectionally with emission angle at all Mach numbers; and the broadband amplification factor decreases as Mach number and emission angle increase. Finally the whistler nozzle is described as a very efficient but inexpensive siren with applications in not only jet excitation but also acoustics.

  6. Scene segmentation through region growing

    NASA Technical Reports Server (NTRS)

    Latty, R. S.

    1984-01-01

    A computer algorithm to segment Landsat Thematic Mapper (TM) images into areas representing surface features is described. The algorithm is based on a region growing approach and uses edge elements and edge element orientation to define the limits of the surface features. Adjacent regions which are not separated by edges are linked to form larger regions. Some of the advantages of scene segmentation over conventional TM image extraction algorithms are discussed, including surface feature analysis on a pixel-by-pixel basis, and faster identification of the pixels in each region. A detailed flow diagram of region growing algorithm is provided.

  7. Segmented amplifier configurations for laser amplifier

    DOEpatents

    Hagen, Wilhelm F.

    1979-01-01

    An amplifier system for high power lasers, the system comprising a compact array of segments which (1) preserves high, large signal gain with improved pumping efficiency and (2) allows the total amplifier length to be shortened by as much as one order of magnitude. The system uses a three dimensional array of segments, with the plane of each segment being oriented at substantially the amplifier medium Brewster angle relative to the incident laser beam and with one or more linear arrays of flashlamps positioned between adjacent rows of amplifier segments, with the plane of the linear array of flashlamps being substantially parallel to the beam propagation direction.

  8. Partially turbulated trailing edge cooling passages for gas turbine nozzles

    DOEpatents

    Thatcher, Jonathan Carl; Burdgick, Steven Sebastian

    2001-01-01

    A plurality of passages are spaced one from the other along the length of a trailing edge of a nozzle vane in a gas turbine. The passages lie in communication with a cavity in the vane for flowing cooling air from the cavity through the passages through the tip of the trailing edge into the hot gas path. Each passage is partially turbulated and includes ribs in an aft portion thereof to provide enhanced cooling effects adjacent the tip of the trailing edge. The major portions of the passages are smooth bore. By this arrangement, reduced temperature gradients across the trailing edge metal are provided. Additionally, the inlets to each of the passages have a restriction whereby a reduced magnitude of compressor bleed discharge air is utilized for trailing edge cooling purposes.

  9. Vortex dynamics in jets from inclined nozzles

    NASA Astrophysics Data System (ADS)

    Webster, D. R.; Longmire, E. K.

    1997-03-01

    Experimental tests were performed on round jets exiting inclined nozzles at a Reynolds number of 9000. Both natural jets and jets forced with single frequencies corresponding to StD=0.25, 0.5, 0.75, and 1.0 were examined. In the natural case, the nozzle incline caused a mild increase in the radial spreading in the plane of azimuthal symmetry. The forcing amplified the asymmetric radial spreading by altering the vortex structure. In general, the inclined vortex rings rolled up at an angle slightly smaller than the nozzle incline angle. As the rings moved downstream, they migrated away from the jet centerline and their incline angle increased. Vortex rings generated at StD=0.5 did not pair because that Strouhal number was near the "preferred" mode. For nozzles with slight inclines, forcing at larger Strouhal numbers led to pairing near x/D=2 in order to achieve the "preferred" mode. For nozzles with larger inclines, the vortex cores broke down before pairing could occur. Forcing at a lower Strouhal number (StD=0.25) yielded ring formation at StD=0.5 and subsequent pairing. Increasing the incline angle moved the pairing location closer to the nozzle lip. Also, the pairing process was found to depend on the nozzle incline angle.

  10. Transient, hypervelocity flow in an axisymmetric nozzle

    NASA Technical Reports Server (NTRS)

    Jacobs, P. A.

    1991-01-01

    The performance of an axisymmetric nozzle was examined which was designed to produce uniform, parallel flow with a nominal Mach number of 8. A free-piston driven shock tube was used to supply the nozzle with high-temperature, high-pressure test gas. Performance was assessed by measuring Pitot pressures across the exit plane of the nozzle and, over the range of operating conditions examined, the nozzle produced satisfactory test flows. However, there were flow disturbances that persisted for significant times after flow initiation. The detailed starting process of the nozzle was also investigated by performing numerical simulations at several nominal test conditions. The classical description of the starting process, based on a quasi-one-dimensional model, provided a reasonable approximation and was used to demonstrate that the starting process could consume a significant fraction of the otherwise usable test gas. This was especially important at high operating enthalpies where nozzle supply conditions were maintained for shorter times. Multidimensional simulations illustrated a mechanism by which the starting process in the actual nozzle could take longer than that predicted by the quasi-one-dimensional analysis. However, the cause of the persistent disturbances observed in the experimental calibration was not identified.

  11. Throat Flow Modelling of Expansion Deflection Nozzles

    NASA Astrophysics Data System (ADS)

    Taylor, N. V.; Hempsell, C. M.

    Modelling of the supersonic flow within a rocket nozzle of both conventional and expansion deflection (ED) design is well handled by Method of Characteristics based algorithms. This approach provides both a predic- tion of the flowfield, and allows efficient optimisation of nozzle shape with respect to length. However, the Method of Characteristics requires a solution of the transonic flow through the nozzle throat to provide initial conditions, and the accuracy of the description of the transonic flow will clearly affect the overall accuracy of the complete nozzle flow calculation. However, it is relatively simple to show that conventional analytical methods for this process break down when applied to the more complex throat geometry of ED nozzles. This requires the use of a time marching solution method, which allows the analysis of the flow within this region even on such advanced configurations. This paper demonstrates this capability, outlines a general method for ED nozzle throat geometric definition, and examines the effect of various throat parameters on the permissible range of ED contours. It is found that the design of length optimised ED nozzles is highly sensitive to small changes in these parameters, and hence they must be selected with care.

  12. Fastrac Nozzle Design, Performance and Development

    NASA Technical Reports Server (NTRS)

    Peters, Warren; Rogers, Pat; Lawrence, Tim; Davis, Darrell; DAgostino, Mark; Brown, Andy

    2000-01-01

    With the goal of lowering the cost of payload to orbit, NASA/MSFC (Marshall Space Flight Center) researched ways to decrease the complexity and cost of an engine system and its components for a small two-stage booster vehicle. The composite nozzle for this Fastrac Engine was designed, built and tested by MSFC with fabrication support and engineering from Thiokol-SEHO (Science and Engineering Huntsville Operation). The Fastrac nozzle uses materials, fabrication processes and design features that are inexpensive, simple and easily manufactured. As the low cost nozzle (and injector) design matured through the subscale tests and into full scale hot fire testing, X-34 chose the Fastrac engine for the propulsion plant for the X-34. Modifications were made to nozzle design in order to meet the new flight requirements. The nozzle design has evolved through subscale testing and manufacturing demonstrations to full CFD (Computational Fluid Dynamics), thermal, thermomechanical and dynamic analysis and the required component and engine system tests to validate the design. The Fastrac nozzle is now in final development hot fire testing and has successfully accumulated 66 hot fire tests and 1804 seconds on 18 different nozzles.

  13. Jet noise suppression by porous plug nozzles

    NASA Technical Reports Server (NTRS)

    Bauer, A. B.; Kibens, V.; Wlezien, R. W.

    1982-01-01

    Jet noise suppression data presented earlier by Maestrello for porous plug nozzles were supplemented by the testing of a family of nozzles having an equivalent throat diameter of 11.77 cm. Two circular reference nozzles and eight plug nozzles having radius ratios of either 0.53 or 0.80 were tested at total pressure ratios of 1.60 to 4.00. Data were taken both with and without a forward motion or coannular flow jet, and some tests were made with a heated jet. Jet thrust was measured. The data were analyzed to show the effects of suppressor geometry on nozzle propulsive efficiency and jet noise. Aerodynamic testing of the nozzles was carried out in order to study the physical features that lead to the noise suppression. The aerodynamic flow phenomena were examined by the use of high speed shadowgraph cinematography, still shadowgraphs, extensive static pressure probe measurements, and two component laser Doppler velocimeter studies. The different measurement techniques correlated well with each other and demonstrated that the porous plug changes the shock cell structure of a standard nozzle into a series of smaller, periodic cell structures without strong shock waves. These structures become smaller in dimension and have reduced pressure variations as either the plug diameter or the porosity is increased, changes that also reduce the jet noise and decrease thrust efficiency.

  14. Hot streak characterization in serpentine exhaust nozzles

    NASA Astrophysics Data System (ADS)

    Crowe, Darrell S.

    Modern aircraft of the United States Air Force face increasingly demanding cost, weight, and survivability requirements. Serpentine exhaust nozzles within an embedded engine allow a weapon system to fulfill mission survivability requirements by providing denial of direct line-of-sight into the high-temperature components of the engine. Recently, aircraft have experienced material degradation and failure along the aft deck due to extreme thermal loading. Failure has occurred in specific regions along the aft deck where concentrations of hot gas have come in contact with the surface causing hot streaks. The prevention of these failures will be aided by the accurate prediction of hot streaks. Additionally, hot streak prediction will improve future designs by identifying areas of the nozzle and aft deck surfaces that require thermal management. To this end, the goal of this research is to observe and characterize the underlying flow physics of hot streak phenomena. The goal is accomplished by applying computational fluid dynamics to determine how hot streak phenomena is affected by changes in nozzle geometry. The present research first validates the computational methods using serpentine inlet experimental and computational studies. A design methodology is then established for creating six serpentine exhaust nozzles investigated in this research. A grid independent solution is obtained on a nozzle using several figures of merit and the grid-convergence index method. An investigation into the application of a second-order closure turbulence model is accomplished. Simulations are performed for all serpentine nozzles at two flow conditions. The research introduces a set of characterization and performance parameters based on the temperature distribution and flow conditions at the nozzle throat and exit. Examination of the temperature distribution on the upper and lower nozzle surfaces reveals critical information concerning changes in hot streak phenomena due to changes

  15. On the space-charge boundary layer inside the nozzle of a cutting torch

    SciTech Connect

    Prevosto, L.; Mancinelli, B.; Kelly, H.

    2009-06-15

    A numerical study of the space-charge sheath adjacent to the nozzle wall of a cutting torch is presented. The hydrodynamic model corresponds to a collision-dominated sheath and does not assume cold ions, so drift-diffusion-type equations are used. Also an improved expression for the ion-neutral momentum transfer is employed rather than the usual constant ion-mean-free-path or constant ion collision frequency approximations. Assuming a constant electron temperature in the sheath and neglecting the electron inertial term, the continuity and momentum equations for ions and electrons, together with Poisson's equation, were solved for the electric potential, ion velocities (both normal and tangential components), and for the ion and electron densities. It was found that both the ion and electron densities present a sudden drop at the sheath-plasma edge. The ion density continues to decrease slowly inside the sheath, while the electron density presents a virtually zero value everywhere inside the sheath, the electron thermal conduction flux to the nozzle wall being negligible. These wall results thus become thermally isolated in spite of the high electron temperature in its adjacency. For a nozzle biasing voltage close to the gas breakdown, it was found that the electric field value is high, reaching a value of about 9x10{sup 6} V m{sup -1} at the exit of the nozzle wall. This value is higher than the average field value across the sheath and is on the order of the breakdown threshold value. This means that an undesired sheath breakdown could occur at the vicinities of the nozzle exit even if the average electric field across the sheath is not strong enough.

  16. Segmented Coil Fails In Steps

    NASA Technical Reports Server (NTRS)

    Stedman, Ronald S.

    1990-01-01

    Electromagnetic coil degrades in steps when faults occur, continues to operate at reduced level instead of failing catastrophically. Made in segments connected in series and separated by electrically insulating barriers. Fault does not damage adjacent components or create hazard. Used to control valves in such critical applications as cooling systems of power generators and chemical process equipment, where flammable liquids or gases handled. Also adapts to electrical control of motors.

  17. Dual nozzle aerodynamic and cooling analysis study

    NASA Technical Reports Server (NTRS)

    Meagher, G. M.

    1981-01-01

    Analytical models to predict performance and operating characteristics of dual nozzle concepts were developed and improved. Aerodynamic models are available to define flow characteristics and bleed requirements for both the dual throat and dual expander concepts. Advanced analytical techniques were utilized to provide quantitative estimates of the bleed flow, boundary layer, and shock effects within dual nozzle engines. Thermal analyses were performed to define cooling requirements for baseline configurations, and special studies of unique dual nozzle cooling problems defined feasible means of achieving adequate cooling.

  18. Segmented combustor

    NASA Technical Reports Server (NTRS)

    Halila, Ely E. (Inventor)

    1994-01-01

    A combustor liner segment includes a panel having four sidewalls forming a rectangular outer perimeter. A plurality of integral supporting lugs are disposed substantially perpendicularly to the panel and extend from respective ones of the four sidewalls. A plurality of integral bosses are disposed substantially perpendicularly to the panel and extend from respective ones of the four sidewalls, with the bosses being shorter than the lugs. In one embodiment, the lugs extend through supporting holes in an annular frame for mounting the liner segments thereto, with the bosses abutting the frame for maintaining a predetermined spacing therefrom.

  19. Molecular disorganization of axons adjacent to human lacunar infarcts

    PubMed Central

    Lee, Monica D.; Tung, Spencer; Vinters, Harry V.; Carmichael, S. Thomas

    2015-01-01

    Cerebral microvascular disease predominantly affects brain white matter and deep grey matter, resulting in ischaemic damage that ranges from lacunar infarcts to white matter hyperintensities seen on magnetic resonance imaging. These lesions are common and result in both clinical stroke syndromes and accumulate over time, resulting in cognitive deficits and dementia. Magnetic resonance imaging studies suggest that these lesions progress over time, accumulate adjacent to prior lesions and have a penumbral region susceptible to further injury. The pathological correlates of this adjacent injury in surviving myelinated axons have not been previously defined. In this study, we sought to determine the molecular organization of axons in tissue adjacent to lacunar infarcts and in the regions surrounding microinfarcts, by determining critical elements in axonal function: the morphology and length of node of Ranvier segments and adjacent paranodal segments. We examined post-mortem brain tissue from six patients with lacunar infarcts and tissue from two patients with autosomal dominant retinal vasculopathy and cerebral leukoencephalopathy (previously known as hereditary endotheliopathy with retinopathy, nephropathy and stroke) who accumulate progressive white matter ischaemic lesions in the form of lacunar and microinfarcts. In axons adjacent to lacunar infarcts yet extending up to 150% of the infarct diameter away, both nodal and paranodal length increase by ∼20% and 80%, respectively, reflecting a loss of normal cell-cell adhesion and signalling between axons and oligodendrocytes. Using premorbid magnetic resonance images, brain regions from patients with retinal vasculopathy and cerebral leukoencephalopathy that harboured periventricular white matter hyperintensities were selected and the molecular organization of axons was determined within these regions. As in regions adjacent to lacunar infarcts, nodal and paranodal length in white matter of these patients is

  20. Subscale solid motor nozzle tests, phase 4 and nozzle materials screening and thermal characterization, phase 5

    NASA Technical Reports Server (NTRS)

    Arnold, J.; Dodson, J.; Laub, B.

    1979-01-01

    Subscale solid motor nozzles containing a baseline material or low cost materials to be considered as potential replacements for the baseline material are designed and tested. Data are presented from tests of four identically designed 2.5 inch throat diameter nozzles and one 7 inch throat diameter nozzle. The screening of new candidate low cost materials, as well as their thermophysical and thermochemical characterization is also discussed.

  1. Method of cooling gas only nozzle fuel tip

    DOEpatents

    Bechtel, William Theodore; Fitts, David Orus; DeLeonardo, Guy Wayne

    2002-01-01

    A diffusion flame nozzle gas tip is provided to convert a dual fuel nozzle to a gas only nozzle. The nozle tip diverts compressor discharge air from the passage feeding the diffusion nozzle air swirl vanes to a region vacated by removal of the dual fuel components, so that the diverted compressor discharge air can flow to and through effusion holes in the end cap plate of the nozzle tip. In a preferred embodiment, the nozzle gas tip defines a cavity for receiving the compressor discharge air from a peripheral passage of the nozzle for flow through the effusion openings defined in the end cap plate.

  2. Method for Forming MEMS-Based Spinning Nozzle

    NASA Technical Reports Server (NTRS)

    Okojie, Robert S. (Inventor)

    2004-01-01

    A nozzle body and assembly for delivering atomized fuel to a combustion chamber. The nozzle body is rotatably mounted onto a substrate. One or more curvilinear fuel delivery channels are in flow communication with an internal fuel distribution cavity formed in the nozzle body. Passage of pressurized fuel through the nozzle body causes the nozzle body to rotate. Components of the nozzle assembly are formed of silicon carbide having surfaces etched by deep reactive ion etching utilizing MEMS technology. A fuel premix chamber is carried on the substrate in flow communication with a supply passage in the nozzle body.

  3. Nuclear thermal rocket nozzle testing and evaluation program

    NASA Technical Reports Server (NTRS)

    Davidian, Kenneth O.; Kacynski, Kenneth J.

    1993-01-01

    Performance characteristics of the Nuclear Thermal Rocket can be enhanced through the use of unconventional nozzles as part of the propulsion system. The Nuclear Thermal Rocket nozzle testing and evaluation program being conducted at the NASA Lewis is outlined and the advantages of a plug nozzle are described. A facility description, experimental designs and schematics are given. Results of pretest performance analyses show that high nozzle performance can be attained despite substantial nozzle length reduction through the use of plug nozzles as compared to a convergent-divergent nozzle. Pretest measurement uncertainty analyses indicate that specific impulse values are expected to be within + or - 1.17 pct.

  4. A performance comparison of two small rocket nozzles

    NASA Technical Reports Server (NTRS)

    Arrington, Lynn A.; Reed, Brian D.; Rivera, Angel, Jr.

    1996-01-01

    An experimental study was conducted on two small rockets (110 N thrust class) to directly compare a standard conical nozzle with a bell nozzle optimized for maximum thrust using the Rao method. In large rockets, with throat Reynolds numbers of greater than 1 x 10(exp 5), bell nozzles outperform conical nozzles. In rockets with throat Reynolds numbers below 1 x 10(exp 5), however, test results have been ambiguous. An experimental program was conducted to test two small nozzles at two different fuel film cooling percentages and three different chamber pressures. Test results showed that for the throat Reynolds number range from 2 x 10(exp 4) to 4 x 10(exp 4), the bell nozzle outperformed the conical nozzle. Thrust coefficients for the bell nozzle were approximately 4 to 12 percent higher than those obtained with the conical nozzle. As expected, testing showed that lowering the fuel film cooling increased performance for both nozzle types.

  5. Exhaust Nozzle Plume Effects on Sonic Boom Test Results for Vectored Nozzles

    NASA Technical Reports Server (NTRS)

    Castner, Raymond

    2012-01-01

    Reducing or eliminating the operational restrictions of supersonic aircraft over populated areas has led to extensive research at NASA. Restrictions were due to the disturbance of the sonic boom, caused by the coalescence of shock waves formed off the aircraft. Recent work has been performed to reduce the magnitude of the sonic boom N-wave generated by airplane components with a focus on shock waves caused by the exhaust nozzle plume. Previous Computational Fluid Dynamics (CFD) analysis showed how the shock wave formed at the nozzle lip interacts with the nozzle boat-tail expansion wave. An experiment was conducted in the 1- by 1-foot Supersonic Wind Tunnel (SWT) at the NASA Glenn Research Center. Results show how the shock generated at the nozzle lip affects the near field pressure signature, and thereby the potential sonic boom contribution for a nozzle at vector angles from 3 to 8 . The experiment was based on the NASA F-15 nozzle used in the Lift and Nozzle Change Effects on Tail Shock experiment, which possessed a large external boat-tail angle. In this case, the large boat-tail angle caused a dramatic expansion, which dominated the near field pressure signature. The impact of nozzle vector angle and nozzle pressure ratio are summarized.

  6. Practical Comparison of Cylindrical Nozzle and De Laval Nozzle for Wire Arc Spraying

    NASA Astrophysics Data System (ADS)

    Matz, Marc-Manuel; Aumiller, Markus

    2014-12-01

    In this article, two different nozzle designs (cylindrical nozzle and de Laval nozzle) are compared for use in wire arc spraying. The choice of nozzle is of particular importance because its geometry has a significant influence on the spraying result. The materials used for spraying are steel and copper. By using the de Laval atomizing gas nozzle, the aim is to improve adhesion on the one hand while reducing cost on the other. These objectives have been achieved for the most part, indicating that continued research and development in this area would be useful. Significant potential exists to optimize the efficiency of both the free gas jet and nozzle which have considerable impact on the gas velocity and thus, ultimately, on the spraying result. The measurements carried out have shown that there is a close correlation between the velocity of the gas flow and atomization of the droplets. An explanatory model for varying spraying results with different wire materials using open nozzle systems with de Laval orifice is given and confirmed. For new burner head constructions, an interaction of the atomizing gas nozzle, the contact tips, and wire materials must be considered to achieve all benefits of a de Laval nozzle.

  7. Practical Comparison of Cylindrical Nozzle and De Laval Nozzle for Wire Arc Spraying

    NASA Astrophysics Data System (ADS)

    Matz, Marc-Manuel; Aumiller, Markus

    2014-09-01

    In this article, two different nozzle designs (cylindrical nozzle and de Laval nozzle) are compared for use in wire arc spraying. The choice of nozzle is of particular importance because its geometry has a significant influence on the spraying result. The materials used for spraying are steel and copper. By using the de Laval atomizing gas nozzle, the aim is to improve adhesion on the one hand while reducing cost on the other. These objectives have been achieved for the most part, indicating that continued research and development in this area would be useful. Significant potential exists to optimize the efficiency of both the free gas jet and nozzle which have considerable impact on the gas velocity and thus, ultimately, on the spraying result. The measurements carried out have shown that there is a close correlation between the velocity of the gas flow and atomization of the droplets. An explanatory model for varying spraying results with different wire materials using open nozzle systems with de Laval orifice is given and confirmed. For new burner head constructions, an interaction of the atomizing gas nozzle, the contact tips, and wire materials must be considered to achieve all benefits of a de Laval nozzle.

  8. Nozzle and shroud assembly mounting structure

    DOEpatents

    Faulder, Leslie J.; Frey, deceased, Gary A.; Nielsen, Engward W.; Ridler, Kenneth J.

    1997-01-01

    The present nozzle and shroud assembly mounting structure configuration increases component life and reduces maintenance by reducing internal stress between the mounting structure having a preestablished rate of thermal expansion and the nozzle and shroud assembly having a preestablished rate of thermal expansion being less than that of the mounting structure. The mounting structure includes an outer sealing portion forming a cradling member in which an annular ring member is slidably positioned. The mounting structure further includes an inner mounting portion to which a hooked end of the nozzle and shroud assembly is attached. As the inner mounting portion expands and contracts, the nozzle and shroud assembly slidably moves within the outer sealing portion.

  9. Nozzle and shroud assembly mounting structure

    DOEpatents

    Faulder, L.J.; Frey, G.A.; Nielsen, E.W.; Ridler, K.J.

    1997-08-05

    The present nozzle and shroud assembly mounting structure configuration increases component life and reduces maintenance by reducing internal stress between the mounting structure having a preestablished rate of thermal expansion and the nozzle and shroud assembly having a preestablished rate of thermal expansion being less than that of the mounting structure. The mounting structure includes an outer sealing portion forming a cradling member in which an annular ring member is slidably positioned. The mounting structure further includes an inner mounting portion to which a hooked end of the nozzle and shroud assembly is attached. As the inner mounting portion expands and contracts, the nozzle and shroud assembly slidably moves within the outer sealing portion. 3 figs.

  10. Natural gas flow through critical nozzles

    NASA Technical Reports Server (NTRS)

    Johnson, R. C.

    1969-01-01

    Empirical method for calculating both the mass flow rate and upstream volume flow rate through critical flow nozzles is determined. Method requires knowledge of the composition of natural gas, and of the upstream pressure and temperature.

  11. On plasma detachment in propulsive magnetic nozzles

    SciTech Connect

    Ahedo, Eduardo; Merino, Mario

    2011-05-15

    Three detachment mechanisms proposed in the literature (via resistivity, via electron inertia, and via induced magnetic field) are analyzed with an axisymmetric model of the expansion of a small-beta, weakly collisional, near-sonic plasma in a diverging magnetic nozzle. The model assumes cold, partially magnetized ions and hot, isothermal, fully magnetized electrons. Different conditions of the plasma beam at the nozzle throat are considered. A central feature is that a positive thrust gain in the nozzle of a plasma thruster is intimately related to the azimuthal current in the plasma being diamagnetic. Then, and contrary to existing expectations, the three aforementioned detachment mechanisms are divergent, that is, the plasma beam diverges outwards of the guide nozzle, further hindering its axial expansion and the thrust efficiency. The rate of divergent detachment is quantified for the small-parameter range of the three mechanisms. Alternative mechanisms for a convergent detachment of the plasma beam are suggested.

  12. One- and two-phase nozzle flows

    SciTech Connect

    Chang, I.S.

    1980-01-01

    A time-dependent technique, in conjunction with the boundary-fitted coordinates system, is applied to solve a gas-only one-phase flow and a fully-coupled, gas-particle two-phase flow inside nozzles with small throat radii of curvature, steep wall gradients, and submerged configurations. The emphasis of the study has been placed on one- and two-phase flow in the transonic region. Various particle sizes and particle mass fractions have been investigated in the two-phase flow. The salient features associated with the two-phase nozzle flow compared with those of the one-phase flow are illustrated through the calculations of the JPL nozzle, the Titan III solid rocket motor, and the submerged nozzle configuration found in the Inertial Upper Stage (IUS) solid rocket motor.

  13. Experiments and Analyses of Distributed Exhaust Nozzles

    NASA Technical Reports Server (NTRS)

    Kinzie, Kevin W.; Schein, David B.; Solomon, W. David, Jr.

    2002-01-01

    Experimental and analytical aeroacoustic properties of several distributed exhaust nozzle (DEN) designs are presented. Significant differences between the designs are observed and correlated back to Computational Fluid Dynamics (CFD) flowfield predictions. Up to 20 dB of noise reduction on a spectral basis and 10 dB on an overall sound pressure level basis are demonstrated from the DEN designs compared to a round reference nozzle. The most successful DEN designs acoustically show a predicted thrust loss of approximately 10% compared to the reference nozzle. Characteristics of the individual mini-jet nozzles that comprise the DEN such as jet-jet shielding and coalescence are shown to play a major role in the noise signature.

  14. Submerged Entry Nozzles that Resist Clogging

    SciTech Connect

    2001-04-01

    Development Of Submerged Entry Nozzles (SENs) Can Incrase Yields, Improve Product Quality, And Increase Productivity In Continuous Casting Of Steel, A Process Used For The Production Of 95% Of Steel In The U.S.

  15. Low thermal stress ceramic turbine nozzle

    DOEpatents

    Glezer, Boris; Bagheri, Hamid; Fierstein, Aaron R.

    1996-01-01

    A turbine nozzle vane assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and being attached to conventional metallic components. The metallic components having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine nozzle vane assembly. The turbine nozzle vane assembly includes an outer shroud and an inner shroud having a plurality of vanes therebetween. Each of the plurality of vanes have a device for heating and cooling a portion of each of the plurality of vanes. Furthermore, the inner shroud has a plurality of bosses attached thereto. A cylindrical member has a plurality of grooves formed therein and each of the plurality of bosses are positioned in corresponding ones of the plurality of grooves. The turbine nozzle vane assembly provides an economical, reliable and effective ceramic component having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the other component.

  16. Self-Adjusting Choke For Nozzle

    NASA Technical Reports Server (NTRS)

    Morrison, Andrew D.

    1991-01-01

    Self-adjusting choke for nozzle enables issuing stream of liquid to remain coherent, despite fluctuations in flow, along greater distance than possible with same nozzle without choke. Flexible membrane with slanted orifices deforms according to upstream pressure in flowing liquid. Advantageous for firefighting, making it possible to direct more concentrated flow of water at flame or hotspot. Also used in mining and for transferring liquids.

  17. Aeroacoustic Resonance with Convergent-Divergent Nozzles

    NASA Technical Reports Server (NTRS)

    Zaman, K. B. M. Q.; Dahl, M. D.

    1999-01-01

    Convergent-divergent nozzles, when run at off-design conditions, often undergo flow resonance accompanied by the emission of a tone. Apart from screech occurring at higher operating pressures, resonance is also common at lower Mach numbers near transonic as well as subsonic conditions. With data from six nozzles of different size and design Mach number, the present paper documents the characteristics of the latter phenomenon that is morphologically quite different from conventional screech. The resonance is due to a feedback loop internal to the nozzle and is apparently driven by unsteady laminar boundary layer separation near the throat of the nozzle. Appropriate boundary layer tripping prior to the throat is found to eliminate or alter most of the tones. The Helmholtz number of the resonance, based on the throat-to-exit length, is found to attain a value of approximately 0.15 at M(sub j)=1 for all nozzles. However, its variation with M(sub j) may be different and depend on the nozzle geometry. With nozzles having larger throat-to-exit angle of divergence, the frequency is found to increase, in some cases having stage jumps to lower frequencies, with increasing operating pressure. With nozzles having smaller angle of divergence, the frequency variation exhibits an increase followed by a decrease involving one prominent stage occurring around transonic (M(sub j)= 1) condition. While the mechanisms remain far from completely clear, a model involving downstream propagating aerodynamic disturbance together with acoustic feedback explains the overall frequency characteristics for most cases.

  18. Exhaust Nozzles for Supersonic Flight with Turbojet Engines

    NASA Technical Reports Server (NTRS)

    Shillito, Thomas B.; Hearth, Donald P.; Cortright, Edgar M.

    1956-01-01

    Good internal performance over a wide range of flight conditions can be obtained with either a plug nozzle or a variable ejector nozzle that can provide a divergent shroud at high pressure ratios. For both the ejector and the plug nozzle, external flow can sometimes cause serious drag losses and, for some plug-nozzle installations, external flow can cause serious internal performance losses. Plug-nozzle cooling and design of the secondary-air-flow systems for ejectors were also considered .

  19. Design of a new type vapor recovery system nozzle

    NASA Astrophysics Data System (ADS)

    Fu, S. H.; Cao, G. J.; Zhang, D. S.

    2016-05-01

    To settle the problem of low-efficiency recovery for Vapor recovery system nozzle, this paper advances a purely mechanical structure of the self-sealing refueling VRS nozzle. The structure, operating principle and controlled process of the nozzle is given. And an application of the nozzle is discussed. All indicated that the nozzle has a reasonable structure, can fuel and vapor recovery simultaneous start and stop. And thus improve the recovery efficiency and reduce oil leakage.

  20. Effect of delta tabs on mixing and axis switching in jets from asymmetric nozzles

    NASA Technical Reports Server (NTRS)

    Zaman, K. B. M. Q.

    1994-01-01

    The effect of delta tabs on mixing and the phenomenon of axis switching in free air jets from various asymmetric nozzles was studied experimentally. Flow visualization and Pitot probe surveys were carried out with a set of small nozzles (D = 1.47 cm) at a jet Mach number, Mj = 1.63. Hot wire measurements for streamwise vorticity were carried out with larger nozzles (D = 6.35 cm) at Mj = 0.31. Jet mixing with the asymmetric nozzles, as indicated by the mass fluxes downstream, was found to be higher than that produced by a circular nozzle. The circular nozzle with four delta tabs, however, produced fluxes much higher than that produced by a asymmetric nozzles themselves or by most of the tab configurations tried with them. Even higher fluxes could be obtained with only a few cases, e.g., with 3:1 rectangular nozzle with two large delta tabs placed on the narrow edges. In this case, the jet 'fanned out' at a large angle after going through one axis switch. The axis switching could be either stopped or augmented with suitable choice of the tab configurations. Two mechanisms are identified governing the phenomenon. One, as described in Ref. 12 and referred to here as the omega(sub Theta)-induced dynamics, is due to differential induced velocities of different segments of a rolled up azimuthal vortical structure. The other is the omega(sub x)-induced dynamics due to the induced velocities of streamwise vortex pairs in the flow. While the former dynamics are responsible for rapid axis switching in periodically forced jets, the effect of the tabs is governed mainly by the latter. It is inferred that both dynamics are active in a natural asymmetric jet issuing from a nozzle having an upstream contraction. The tendency for axis switching caused by the omega(sub Theta)-induced dynamics is resisted by the omega(sub x)-induced dynamics, leading to a delayed or no switch over in that case. In jets from orifices and in screeching jets, the omega(sub Theta)-induced dynamics

  1. Acoustic Measurements of Rectangular Nozzles With Bevel

    NASA Technical Reports Server (NTRS)

    Bridges, James E.

    2012-01-01

    A series of convergent rectangular nozzles of aspect ratios 2:1, 4:1, and 8:1 were constructed with uniform exit velocity profiles. Additional nozzles were constructed that extended the wide lip on one side of these nozzles to form beveled nozzles. Far-field acoustic measurements were made and analyzed, and the results presented. The impact of aspect ratio on jet noise was similar to that of enhanced mixing devices: reduction in aft, peak frequency noise with an increase in broadside, high frequency noise. Azimuthally, it was found that rectangular jets produced more noise directed away from their wide sides than from their narrow sides. The azimuthal dependence decreased at aft angles where noise decreased. The effect of temperature, keeping acoustic Mach number constant, was minimal. Since most installations would have the observer on the wide size of the nozzle, the increased high frequency noise has a deleterious impact on the observer. Extending one wide side of the rectangular nozzle, evocative of an aft deck in an installed propulsion system, increased the noise of the jet with increasing length. The impact of both aspect ratio and bevel length were relatively well behaved, allowing a simple bilinear model to be constructed relative to a simple round jet.

  2. Nozzle Thrust Optimization While Reducing Jet Noise

    NASA Technical Reports Server (NTRS)

    Seiner, J. M.; Gilinsky, M. M.

    1995-01-01

    A Bluebell nozzle design concept is proposed for jet noise reduction with minimal thrust loss or even thrust augmentation. A Bluebell nozzle has a sinusoidal lip line edge (chevrons) and a sinusoidal cross section shape with linear amplitude increasing downstream in the divergent nozzle part (corrugations). The experimental tests of several Bluebell nozzle designs have shown nose reduction relative to a convergent-divergent round nozzle with design exhaust number M(e) = 1.5. The best design provides an acoustic benefit near 4dB with about 1 percent thrust augmentation. For subsonic flow ((M(e)= 0.6)), the tests indicated that the present method for design of Bluebell nozzles gives less acoustic benefit and in most cases jet noise increased. The proposed designs incorporate analytical theory and 2D and 3D numerical simulations. Full Navier-Stokes and Euler solvers were utilized. Boundary layer effects were used. Several different designs were accounted for in the Euler applications.

  3. Jet-diffuser Ejector - Attached Nozzle Design

    NASA Technical Reports Server (NTRS)

    Alperin, M.; Wu, J. J.

    1980-01-01

    Attached primary nozzles were developed to replace the detached nozzles of jet-diffuser ejectors. Slotted primary nozzles located at the inlet lip and injecting fluid normal to the thrust axis, and rotating the fluid into the thrust direction using the Coanda Effect were investigated. Experiments indicated excessive skin friction or momentum cancellation due to impingement of opposing jets resulted in performance degradation. This indicated a desirability for location and orientation of the injection point at positions removed from the immediate vicinity of the inlet surface, and at an acute angle with respect to the thrust axis. Various nozzle designs were tested over a range of positions and orientations. The problems of aircraft integration of the ejector, and internal and external nozzle losses were also considered and a geometry for the attached nozzles was selected. The effect of leaks, protrusions, and asymmetries in the ejector surfaces was examined. The results indicated a relative insensitivity to all surface irregularities, except for large protrusions at the throat of the ejector.

  4. Decomposing Solid Micropropulsion Nozzle Performance Issues

    NASA Technical Reports Server (NTRS)

    Reed, Brian

    2003-01-01

    Micropropulsion technology is essential to the success of miniaturized spacecraft and can provide ultra-precise propulsion for small spacecraft. NASA Glenn Research Center has envisioned a micropropulsion concept that utilizes decomposing solid propellants for a valveless, leak-free propulsion system. Among the technical challenges of this decomposing solid micropropulsion concept is optimization of miniature, rectangular nozzles. A number of flat micronozzles were tested with ambient-temperature nitrogen and helium gas in a vacuum facility. The thrusters were etched out of silicon and had throat widths on the order of 350 microns and throat depths on the order of 250 microns. While these were half-sections of thrusters (two would be bonded together before firing), testing provided the performance trend for nozzles of this scale and geometry. Area ratios from 1 to 25 were tested, with thrust measured using an inverted pendulum thrust stand for nitrogen flows and a torsional thrust stand for helium. In the nitrogen testing, peak nozzle performance was achieved around area ratio of 5. In the helium series, nozzle performance peaked for the smallest nozzle tested area ratio 1.5. For both gases, there was a secondary performance peak above area ratio 15. At low chamber pressures (< 1.6 atm), nitrogen provided higher nozzle performance than helium. The performance curve for helium was steeper, however, and it appeared that helium would provide better performance than nitrogen at higher chamber pressures.

  5. Segmental overlap: foot drop in S1 radiculopathy.

    PubMed

    Voermans, N C; Koetsveld, A C; Zwarts, M J

    2006-07-01

    Knowledge of segmental innervation of skeletal muscles is essential for diagnosing lumbar radiculopathy. Myotomes and dermatomes are traditionally thought to be innervated by a single spinal segment, but experimental studies have shown that this pattern of segmental innervation allows considerable overlap. This implies that muscles (or dermatomes) are innervated not only by axons of one spinal segment, but also partially by axons of adjacent spinal levels. We describe a patient in whom overlap in segmental innervation complicated adequate diagnosis of a recurrent lumbar hernia. Further, we present an outline of electrophysiological and anatomical studies on segmental innervation. PMID:16523224

  6. Aerospike nozzle contour design and its performance validation

    NASA Astrophysics Data System (ADS)

    Wang, Chang-Hui; Liu, Yu; Qin, Li-Zi

    2009-06-01

    A simplified design and optimization method of aerospike nozzle contour and the results of tests and numerical simulation of aerospike nozzles are presented. The primary nozzle contour is approximated by two circular arcs and a parabola; the plug contour is approximated by a parabola and a third-order polynomial. The maximum total impulse from sea level to design altitude is adopted as objective to optimize the aerospike nozzle contour. Experimental studies were performed on a 6-cell tile-shaped aerospike nozzle, a 1-cell linear aerospike nozzle and a 3-cell aerospike nozzle with round-to-rectangle (RTR) primary nozzles designed by method proposed in present paper. Three aerospike nozzles achieved good altitude compensation capacities in the tests and still had better performance at off-design altitudes compared with that of the bell-shaped nozzle. In cold-flow tests, 6-cell tile-shaped aerospike nozzle and 1-cell linear aerospike nozzle obtained high thrust efficiency at design altitude. Employing gas H 2/gas O 2 (GH 2/GO 2) as propellants, hot-firing tests were carried out on a 3-cell aerospike nozzle engine with RTR primary nozzles. The performance was obtained under two nozzle pressure ratios (NPR) lower than design altitude. Efficiency reached 92.0-93.5% and 95.0-96.0%, respectively. Pressure distribution along plug ramp was measured and the effects of variation in the amount of base bleed on performance were also examined in the tests.

  7. [Segmental neurofibromatosis].

    PubMed

    Zulaica, A; Peteiro, C; Pereiro, M; Pereiro Ferreiros, M; Quintas, C; Toribio, J

    1989-01-01

    Four cases of segmental neurofibromatosis (SNF) are reported. It is a rare entity considered to be a localized variant of neurofibromatosis (NF)-Riccardi's type V. Two cases are male and two female. The lesions are located to the head in a patient and the other three cases in the trunk. No family history nor transmission to progeny were manifested. The rest of the organs are undamaged. PMID:2502696

  8. Wall Angle Effects on Nozzle Separation Stability

    NASA Astrophysics Data System (ADS)

    Aghababaie, A.; Taylor, N.

    The presence of asymmetric side loads due to unstable separation within over-expanded rocket nozzles is well documented. Although progress has been made in developing understanding of this phenomenon through numerical and experimental means, the causes of these side loads have yet to be fully explained. The hypothesis examined within this paper is that there is a relationship between nozzle wall angle at the point of separation, and the stability of the flow separation. This was achieved through an experimental investigation of a series of subscale over-expanded conical nozzles with half-angles of 8.3°, 10.4°, 12.6° and 14.8°. All had overall area ratios of 16:1, with separation occurring at approximately half the nozzle length (i.e. area ration of 4:1) under an overall pressure ratio of approximately 7:1 using air as the working fluid. The structure of exhaust flow was observed and analysed by use of an optimised Schlieren visualisation system, coupled with a high speed digital camera. The 12.6° and 14.8° nozzles exhaust flow were seen to be stable throughout the recorded test period of 10 seconds. However, a small number of large fluctuations in the jet angle were seen to be present within the flowfield of the 10.4° nozzle, occurring at apparently random intervals through the test period. The flowfield of the 8.3° nozzle demonstrated near continuous, large angle deviations in the jet, with flow patterns containing thickened shear layers and apparent reattachment to the wall, something not previously identified in conical nozzles. These results were used to design a truncated ideal contour with an exit angle of over 10 degrees, in order to assess the possibility of designing conventional nozzles that separate stably over a wide range of pressure ratios. These tests were successful, potentially providing a simpler, cheaper alternative to altitude compensating nozzle devices. However, more work determining the nature of the separation and its causes is

  9. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  10. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  11. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  12. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  13. Analysis and design of three dimensional supersonic nozzles. Volume 4: Similarity laws for nozzle flows

    NASA Technical Reports Server (NTRS)

    Ferri, A.; Roffe, G.

    1972-01-01

    The development of nozzles for hypersonic aircraft is discussed. The simulation of actual nozzle flows with low temperature nonreactive gases is described. Mathematical models of the flow equations nd thermodynamic relations are developed. Cold flow simulation tests were conducted and the results are included.

  14. Nuclear propulsion apparatus with alternate reactor segments

    DOEpatents

    Szekely, Thomas

    1979-04-03

    1. Nuclear propulsion apparatus comprising: A. means for compressing incoming air; B. nuclear fission reactor means for heating said air; C. means for expanding a portion of the heated air to drive said compressing means; D. said nuclear fission reactor means being divided into a plurality of radially extending segments; E. means for directing a portion of the compressed air for heating through alternate segments of said reactor means and another portion of the compressed air for heating through the remaining segments of said reactor means; and F. means for further expanding the heated air from said drive means and the remaining heated air from said reactor means through nozzle means to effect reactive thrust on said apparatus.

  15. Parametric study of solar thermal rocket nozzle performance

    NASA Technical Reports Server (NTRS)

    Pearson, J. Boise; Landrum, D. Brian; Hawk, Clark W.

    1995-01-01

    This paper details a numerical investigation of performance losses in low-thrust solar thermal rocket nozzles. The effects of nozzle geometry on three types of losses were studied; finite rate dissociation-recombination kinetic losses, two dimensional axisymmetric divergence losses, and compressible viscous boundary layer losses. Short nozzle lengths and supersonic flow produce short residence times in the nozzle and a nearly frozen flow, resulting in large kinetic losses. Variations in geometry have a minimal effect on kinetic losses. Divergence losses are relatively small, and careful shaping of the nozzle can nearly eliminate them. The boundary layer in these small nozzles can grow to a major fraction of nozzle radius, and cause large losses. These losses are attributed to viscous drag on the nozzle walls and flow blockage by the boundary layer, especially in the throat region. Careful shaping of the nozzle can produce a significant reduction in viscous losses.

  16. Ground test of the D shaped vented thrust vectoring nozzle

    NASA Technical Reports Server (NTRS)

    Esker, D. W.

    1976-01-01

    Static ground tests of a large scale lift/cruise thrust vectoring nozzle were conducted to establish: (1) vectoring performance 'in' and 'out' of ground effect; (2) thrust spoilage capability; (3) compatibility of the nozzle with a turbotip fan; and (4) the nozzle structural temperature distribution. Vectoring performance of a short coupled, vented nozzle design on a large scale, (60%) basis was compared with small scale (4.5%) test nozzle results. The test nozzle was a "boilerplate" model of the MCAIR "D" vented nozzle configured for operation with the LF336/J85 turbotip lift fan system. Calibration of the LF336/J85 test fan with a simple convergent nozzle was performed with four different nozzle exit areas to establish reference thrust, nozzle pressure ratio, and nozzle corrected flow characteristics for comparison with the thrust vectoring nozzle data. Thrust vectoring tests with the 'D' vented nozzle were conducted over the range of vector angles between 0 and 117 deg for several different nozzle exit areas.

  17. Aerodynamic performance of flared fan nozzles used as inlets

    NASA Technical Reports Server (NTRS)

    Dietrich, D. A.; Keith, T. G.; Kelm, G. G.

    1976-01-01

    Tests were conducted in a low speed wind tunnel to determine the aerodynamic performance of several flared fan nozzles. Each of the flared nozzles was a downstream-facing inlet to a model fan that was used to simulate a variable pitch fan during reverse thrust operation. The total pressure recovery of each of the flared nozzles as well as that of an unflared nozzle and a serrated flare nozzle was obtained for comparison. The aerodynamic performance of a selected flared nozzle was considered in further detail. The nozzle surface pressures for a flared nozzle were also determined. Results indicated that the differences in aerodynamic performance among the nozzles were most apparent at the wind-tunnel-off condition. A nonzero free stream velocity significantly reduced the perforamnce of all the nozzles, and crosswind flow (free stream flow perpendicular to the model axis) further reduced the performance of the nozzles. The unflared nozzle and the serrated flare nozzle had reduced aerodynamic performance compared to a solid surface flared nozzle.

  18. Upper Stage Engine Composite Nozzle Extensions

    NASA Technical Reports Server (NTRS)

    Valentine, Peter G.; Allen, Lee R.; Gradl, Paul R.; Greene, Sandra E.; Sullivan, Brian J.; Weller, Leslie J.; Koenig, John R.; Cuneo, Jacques C.; Thompson, James; Brown, Aaron; Shigley, John K.; Dovey, Henry N.; Roberts, Robert K.

    2015-01-01

    Carbon-carbon (C-C) composite nozzle extensions are of interest for use on a variety of launch vehicle upper stage engines and in-space propulsion systems. The C-C nozzle extension technology and test capabilities being developed are intended to support National Aeronautics and Space Administration (NASA) and United States Air Force (USAF) requirements, as well as broader industry needs. Recent and on-going efforts at the Marshall Space Flight Center (MSFC) are aimed at both (a) further developing the technology and databases for nozzle extensions fabricated from specific CC materials, and (b) developing and demonstrating low-cost capabilities for testing composite nozzle extensions. At present, materials development work is concentrating on developing a database for lyocell-based C-C that can be used for upper stage engine nozzle extension design, modeling, and analysis efforts. Lyocell-based C-C behaves in a manner similar to rayon-based CC, but does not have the environmental issues associated with the use of rayon. Future work will also further investigate technology and database gaps and needs for more-established polyacrylonitrile- (PAN-) based C-C's. As a low-cost means of being able to rapidly test and screen nozzle extension materials and structures, MSFC has recently established and demonstrated a test rig at MSFC's Test Stand (TS) 115 for testing subscale nozzle extensions with 3.5-inch inside diameters at the attachment plane. Test durations of up to 120 seconds have been demonstrated using oxygen/hydrogen propellants. Other propellant combinations, including the use of hydrocarbon fuels, can be used if desired. Another test capability being developed will allow the testing of larger nozzle extensions (13.5- inch inside diameters at the attachment plane) in environments more similar to those of actual oxygen/hydrogen upper stage engines. Two C-C nozzle extensions (one lyocell-based, one PAN-based) have been fabricated for testing with the larger

  19. Segmental neurofibromatosis.

    PubMed

    Sobjanek, Michał; Dobosz-Kawałko, Magdalena; Michajłowski, Igor; Pęksa, Rafał; Nowicki, Roman

    2014-12-01

    Segmental neurofibromatosis or type V neurofibromatosis is a rare genodermatosis characterized by neurofibromas, café-au-lait spots and neurofibromas limited to a circumscribed body region. The disease may be associated with systemic involvement and malignancies. The disorder has not been reported yet in the Polish medical literature. A 63-year-old Caucasian woman presented with a 20-year history of multiple, flesh colored, dome-shaped, soft to firm nodules situated in the right lumbar region. A histopathologic evaluation of three excised tumors revealed neurofibromas. No neurological and ophthalmologic symptoms of neurofibromatosis were diagnosed. PMID:25610358

  20. Segmental neurofibromatosis.

    PubMed

    Adigun, Chris G; Stein, Jennifer

    2011-01-01

    A 59-year-old man presented for evaluation and excision of non-tender, fleshy nodules that were arranged in a dermatomal distribution from the left side of the chest to the left axilla. A biopsy specimen of a nodule was consistent with a neurofibroma. Owing to the lack of other cutaneous findings, the lack of a family history of neurofibromatosis, and the dermatomal distribution of the neurofibromas, this patient met the criteria for a diagnosis of segmental neurofibromatosis (SNF) according to Riccardi's definition of SNF and classification of neurofibromatosis. Because the patient has no complications of neurofibromatosis 1 no medical treatment is required. PMID:22031651

  1. Segmental neurofibromatosis

    PubMed Central

    Dobosz-Kawałko, Magdalena; Michajłowski, Igor; Pęksa, Rafał; Nowicki, Roman

    2014-01-01

    Segmental neurofibromatosis or type V neurofibromatosis is a rare genodermatosis characterized by neurofibromas, café-au-lait spots and neurofibromas limited to a circumscribed body region. The disease may be associated with systemic involvement and malignancies. The disorder has not been reported yet in the Polish medical literature. A 63-year-old Caucasian woman presented with a 20-year history of multiple, flesh colored, dome-shaped, soft to firm nodules situated in the right lumbar region. A histopathologic evaluation of three excised tumors revealed neurofibromas. No neurological and ophthalmologic symptoms of neurofibromatosis were diagnosed. PMID:25610358

  2. Integrity of the Plasma Magnetic Nozzle

    NASA Technical Reports Server (NTRS)

    Gerwin, Richard A.

    2009-01-01

    This report examines the physics governing certain aspects of plasma propellant flow through a magnetic nozzle, specifically the integrity of the interface between the plasma and the nozzle s magnetic field. The injection of 100s of eV plasma into a magnetic flux nozzle that converts thermal energy into directed thrust is fundamental to enabling 10 000s of seconds specific impulse and 10s of kW/kg specific power piloted interplanetary propulsion. An expression for the initial thickness of the interface is derived and found to be approx.10(exp -2) m. An algorithm is reviewed and applied to compare classical resistivity to gradient-driven microturbulent (anomalous) resistivity, in terms of the spatial rate and time integral of resistive interface broadening, which can then be related to the geometry of the nozzle. An algorithm characterizing plasma temperature, density, and velocity dependencies is derived and found to be comparable to classical resistivity at local plasma temperatures of approx. 200 eV. Macroscopic flute-mode instabilities in regions of "adverse magnetic curvature" are discussed; a growth rate formula is derived and found to be one to two e-foldings of the most unstable Rayleigh-Taylor (RT) mode. After establishing the necessity of incorporating the Hall effect into Ohm s law (allowing full Hall current to flow and concomitant plasma rotation), a critical nozzle length expression is derived in which the interface thickness is limited to about 1 ion gyroradius.

  3. Nozzle dam having a unitary plug

    DOEpatents

    Veronesi, L.; Wepfer, R.M.

    1992-12-15

    Apparatus for sealing the primary-side coolant flow nozzles of a nuclear steam generator is disclosed. The steam generator has relatively small diameter manway openings for providing access to the interior of the steam generator including the inside surface of each nozzle, the manway openings having a diameter substantially less than the inside diameter of each nozzle. The apparatus includes a bracket having an outside surface for matingly sealingly engaging the inside surface of the nozzle. The bracket also has a plurality of openings longitudinally therethrough and a plurality of slots transversely therein in communication with each opening. A plurality of unitary plugs sized to pass through the manway opening are matingly sealingly disposed in each opening of the bracket for sealingly plugging each opening. Each plug includes a plurality of arms operable to engage the slots of the bracket for connecting each plug to the bracket, so that the nozzle is sealed as the plugs seal the openings and are connected to the bracket. 16 figs.

  4. Nozzle dam having a unitary plug

    DOEpatents

    Veronesi, Luciano; Wepfer, Robert M.

    1992-01-01

    Apparatus for sealing the primary-side coolant flow nozzles of a nuclear steam generator. The steam generator has relatively small diameter manway openings for providing access to the interior of the steam generator including the inside surface of each nozzle, the manway openings having a diameter substantially less than the inside diameter of each nozzle. The apparatus includes a bracket having an outside surface for matingly sealingly engaging the inside surface of the nozzle. The bracket also has a plurality of openings longitudinally therethrough and a plurality of slots transversely therein in communication with each opening. A plurality of unitary plugs sized to pass through the manway opening are matingly sealingly disposed in each opening of the bracket for sealingly plugging each opening. Each plug includes a plurality of arms operable to engage the slots of the bracket for connecting each plug to the bracket, so that the nozzle is sealed as the plugs seal the openings and are connected to the bracket.

  5. Aeroelastic Modeling of a Nozzle Startup Transient

    NASA Technical Reports Server (NTRS)

    Wang, Ten-See; Zhao, Xiang; Zhang, Sijun; Chen, Yen-Sen

    2014-01-01

    Lateral nozzle forces are known to cause severe structural damage to any new rocket engine in development during test. While three-dimensional, transient, turbulent, chemically reacting computational fluid dynamics methodology has been demonstrated to capture major side load physics with rigid nozzles, hot-fire tests often show nozzle structure deformation during major side load events, leading to structural damages if structural strengthening measures were not taken. The modeling picture is incomplete without the capability to address the two-way responses between the structure and fluid. The objective of this study is to develop a tightly coupled aeroelastic modeling algorithm by implementing the necessary structural dynamics component into an anchored computational fluid dynamics methodology. The computational fluid dynamics component is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, while the computational structural dynamics component is developed under the framework of modal analysis. Transient aeroelastic nozzle startup analyses at sea level were performed, and the computed transient nozzle fluid-structure interaction physics presented,

  6. Low Noise Exhaust Nozzle Technology Development

    NASA Technical Reports Server (NTRS)

    Majjigi, R. K.; Balan, C.; Mengle, V.; Brausch, J. F.; Shin, H.; Askew, J. W.

    2005-01-01

    NASA and the U.S. aerospace industry have been assessing the economic viability and environmental acceptability of a second-generation supersonic civil transport, or High Speed Civil Transport (HSCT). Development of a propulsion system that satisfies strict airport noise regulations and provides high levels of cruise and transonic performance with adequate takeoff performance, at an acceptable weight, is critical to the success of any HSCT program. The principal objectives were to: 1. Develop a preliminary design of an innovative 2-D exhaust nozzle with the goal of meeting FAR36 Stage III noise levels and providing high levels of cruise performance with a high specific thrust for Mach 2.4 HSCT with a range of 5000 nmi and a payload of 51,900 lbm, 2. Employ advanced acoustic and aerodynamic codes during preliminary design, 3. Develop a comprehensive acoustic and aerodynamic database through scale-model testing of low-noise, high-performance, 2-D nozzle configurations, based on the preliminary design, and 4. Verify acoustic and aerodynamic predictions by means of scale-model testing. The results were: 1. The preliminary design of a 2-D, convergent/divergent suppressor ejector nozzle for a variable-cycle engine powered, Mach 2.4 HSCT was evolved, 2. Noise goals were predicted to be achievable for three takeoff scenarios, and 3. Impact of noise suppression, nozzle aerodynamic performance, and nozzle weight on HSCT takeoff gross weight were assessed.

  7. Low thrust viscous nozzle flow fields prediction

    NASA Technical Reports Server (NTRS)

    Liaw, Goang-Shin

    1987-01-01

    An existing Navier-Stokes code (PARC2D) was used to compute the nozzle flow field. Grids were generated by the interactive grid generator codes TBGG and GENIE. All computations were made on the NASA/MSFC CRAY X-MP computer. Comparisons were made between the computations and MSFC in-house wall pressure measurements for CO2 flow through a conical nozzle having an area ratio of 40. Satisfactory agreements exist between the computations and measurements for different stagnation pressures of 29.4, 14.7, and 7.4 psia, at stagnation temperature of 1060 R. However, agreements did not match precisely near the nozzle exit. Several reasons for the lack of agreement are possible. The computational code assumes a constant gas gamma, whereas the gamma i.e. the specific heat ratio for CO2 varied from 1.22 in the plenum chamber to 1.38 at the nozzle exit. The computations also assumes adiabatic and no-slip walls. Both assumptions may not be correct. Finally, it is possible that condensation occurs during the nozzle expansion at the low stagnation pressure. The next phase of the work will incorporate variable gamma and slip wall boundary conditions in the computational code and develop a more accurate computer code.

  8. Experimental study of coaxial nozzle exhaust noise. [acoustic measurements

    NASA Technical Reports Server (NTRS)

    Goodykoontz, J. H.; Stone, J. R.

    1979-01-01

    Experimental results are presented for static acoustic model tests of various geometrical configurations of coaxial nozzles operating over a range of flow conditions. The geometrical configurations consisted of nozzles with coplanar and non-coplanar exit planes and various exhaust area ratios. Primary and secondary nozzle flows were varied independently over a range of nozzle pressure ratios from 1.4 to 3.0 and gas temperatures from 280 to 1100 K. Acoustic data are presented for the conventional mode of coaxial nozzle operation as well as for the inverted velocity profile mode. Comparisons are presented to show the effect of configuration and flow changes on the acoustic characteristics of the nozzles.

  9. Design, fabrication and test of the RL10 derivative II chamber/primary nozzle

    NASA Technical Reports Server (NTRS)

    Marable, R. W.

    1989-01-01

    The design, fabrication and test of the RL10-II chamber/primary nozzle was accomplished as part of the RL10 Product Improvement Program (PIP). The overall goal of the RL10 PIP was to gain the knowledge and experience necessary to develop new cryogenic upper stage engines to fulfill future NASA requirements. The goal would be reached by producing an RL10 engine designed to be reusable, operate at several thrust levels, and have increased performance. The goals for the chamber/primary nozzle task were: (1) to design a reusable assembly capable of operation at increased mixture ratio and low thrust; (2) to fabricate three assemblies using new or updated techniques where possible; and (3) to test one assembly to verify the design and construction. The design and fabrication phases produced an assembly having improved features such as single piece reinforcing band segments (i.e., Mae West segments) and relocated tube exit braze joints (i.e., hooked tube exit). In addition, a computer program was developed to design the chamber tubes to meet both performance and heat transfer requirements. The test phase showed the specific impulse of the test bed engine system to be as predicted. These results, along with the heat transfer data obtained, sufficiently proved the overall design of the RL10-II recontoured and shortened chamber/primary nozzle assembly.

  10. Segmental Aortic Stiffening Contributes to Experimental Abdominal Aortic Aneurysm Development

    PubMed Central

    Raaz, Uwe; Zöllner, Alexander M.; Schellinger, Isabel N.; Toh, Ryuji; Nakagami, Futoshi; Brandt, Moritz; Emrich, Fabian C.; Kayama, Yosuke; Eken, Suzanne; Adam, Matti; Maegdefessel, Lars; Hertel, Thomas; Deng, Alicia; Jagger, Ann; Buerke, Michael; Dalman, Ronald L.; Spin, Joshua M.; Kuhl, Ellen; Tsao, Philip S.

    2015-01-01

    Background Stiffening of the aortic wall is a phenomenon consistently observed in age and in abdominal aortic aneurysm (AAA). However, its role in AAA pathophysiology is largely undefined. Methods and Results Using an established murine elastase-induced AAA model, we demonstrate that segmental aortic stiffening (SAS) precedes aneurysm growth. Finite element analysis (FEA) reveals that early stiffening of the aneurysm-prone aortic segment leads to axial (longitudinal) wall stress generated by cyclic (systolic) tethering of adjacent, more compliant wall segments. Interventional stiffening of AAA-adjacent aortic segments (via external application of surgical adhesive) significantly reduces aneurysm growth. These changes correlate with reduced segmental stiffness of the AAA-prone aorta (due to equalized stiffness in adjacent segments), reduced axial wall stress, decreased production of reactive oxygen species (ROS), attenuated elastin breakdown, and decreased expression of inflammatory cytokines and macrophage infiltration, as well as attenuated apoptosis within the aortic wall. Cyclic pressurization of segmentally stiffened aortic segments ex vivo increases the expression of genes related to inflammation and extracellular matrix (ECM) remodeling. Finally, human ultrasound studies reveal that aging, a significant AAA risk factor, is accompanied by segmental infrarenal aortic stiffening. Conclusions The present study introduces the novel concept of segmental aortic stiffening (SAS) as an early pathomechanism generating aortic wall stress and triggering aneurysmal growth, thereby delineating potential underlying molecular mechanisms and therapeutic targets. In addition, monitoring SAS may aid the identification of patients at risk for AAA. PMID:25904646

  11. Flow-Field Surveys for Rectangular Nozzles

    NASA Technical Reports Server (NTRS)

    Zaman, K. B. M. Q.

    2012-01-01

    Flow field survey results for three rectangular nozzles are presented for a low subsonic condition obtained primarily by hot-wire anemometry. The three nozzles have aspect ratios of 2:1, 4:1 and 8:1. A fourth case included has 2:1 aspect ratio with chevrons added to the long edges. Data on mean velocity, turbulent normal and shear stresses as well as streamwise vorticity are presented covering a streamwise distance up to sixteen equivalent diameters from the nozzle exit. These detailed flow properties, including initial boundary layer characteristics, are usually difficult to measure in high speed flows and the primary objective of the study is to aid ongoing and future computational and noise modeling efforts.

  12. Plume detachment from a magnetic nozzle

    SciTech Connect

    Deline, Christopher A.; Bengtson, Roger D.; Breizman, Boris N.; Tushentsov, Mikhail R.; Jones, Jonathan E.; Chavers, D. Greg; Dobson, Chris C.; Schuettpelz, Branwen M.

    2009-03-15

    High-powered electric propulsion thrusters utilizing a magnetized plasma require that plasma exhaust detach from the applied magnetic field in order to produce thrust. This paper presents experimental results demonstrating that a sufficiently energetic and flowing plasma can indeed detach from a magnetic nozzle. Microwave interferometer and probe measurements provide plume density, electron temperature, and ion flux measurements in the nozzle region. Measurements of ion flux show a low-beta plasma plume which follows applied magnetic field lines until the plasma kinetic pressure reaches the magnetic pressure and a high-beta plume expanding ballistically afterward. Several magnetic configurations were tested including a reversed field nozzle configuration. Despite the dramatic change in magnetic field profile, the reversed field configuration yielded little measurable change in plume trajectory, demonstrating the plume is detached. Numerical simulations yield density profiles in agreement with the experimental results.

  13. Design of high pressure waterjet nozzles

    NASA Technical Reports Server (NTRS)

    Mazzoleni, Andre P.

    1994-01-01

    The Hydroblast Research Cell at Marshall Space Flight Center is used to investigate the use of high pressure waterjets to strip paint, grease, adhesive and thermal spray coatings from various substrates. Current methods of cleaning often use ozone depleting chemicals (ODC) such as chlorinated solvents. High pressure waterjet cleaning has proven to be a viable alternative to the use of solvents. A popular method of waterjet cleaning involves the use of a rotating, multijet, high pressure water nozzle which is robotically controlled. This method enables rapid cleaning of a large area, but problems such as incomplete coverage and damage to the substrate from the waterjet have been observed. This report summarizes research consisting of identifying and investigating the basic properties of rotating, multijet, high pressure water nozzles, and how particular designs and modes of operation affect such things as stripping rate, standoff distance and completeness of coverage. The study involved computer simulations, an extensive literature review, and experimental studies of different nozzle designs.

  14. Advanced Solid Rocket Motor nozzle development status

    NASA Astrophysics Data System (ADS)

    Kearney, W. J.; Moss, J. D.

    1993-06-01

    This paper presents a status update of the design and development of an improved nozzle for the Advanced Solid Rocket Motor (ASRM). The ASRM nozzle incorporates advanced state-of-the-art design features and materials which contribute to enhanced safety, reliability, performance, and producibility for the space shuttle boosters. During 1992 the nozzle design progressed through a successful Preliminary Design Review (PDR). An improved ablative material development program also culminated in the selection of new standard and low density carbon cloth phenolic prepreg offering reduced variability and improved process attributes. A subscale motor test series to evaluate new materials and design features was also completed. An overview update of the matured design characteristics, supporting analysis, key development-program results and program status and plans is reported.

  15. Gas turbine exhaust nozzle. [for noise reduction

    NASA Technical Reports Server (NTRS)

    Straight, D. M. (Inventor)

    1973-01-01

    An elongated hollow string is disposed in an exhaust nozzle combustion chamber and communicates with an air source through hollow struts at one end. The other end of the string is bell-mouth shaped and extends over the front portion of a nozzle plug. The bell-mouth may be formed by pivotally mounted flaps or leaves which are used to vary the exhaust throat area and the area between the plug and the leaves. Air from the engine inlet flows into the string and also between the combustion chamber and a housing disposed around the chamber. The air cools the plug and serves as a low velocity inner core of secondary gas to provide noise reduction for the primary exhaust gas while the other air, when it exits from the nozzle, forms an outer low velocity layer to further reduce noise. The structure produces increased thrust in a turbojet or turbofan engine.

  16. Aging problems in graphite phenolic nozzle liners

    NASA Technical Reports Server (NTRS)

    Mccorkle, G. S.

    1979-01-01

    Age related cracks in the graphite phenolic linear and/or ATJ insert in several nine year old Altair IIA solid rocket nozzles were investigated and determined to be limited to a single lot of nozzles. Test results and photomicrographs of fracture surfaces are presented which establish that in the discrepant nozzles the bond between the graphite fibers and the phenolic resin was tenacious, resulting in a nearly homogenous behavior. These materials are shown to have a relatively weak resin - fiber bond and behave more like a released fiber composite. Lot qualification fiber directional tensile strength and the chemical composition of the two materials were comparable, indicating that standard acceptance testing could not have differentiated between the desirable and undesirable material. Review of processing records failed to reveal any cause for the difference in the aging characteristics.

  17. Feasibility Assessment of Thermal Barriers for RSRM Nozzle Joint Locations

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M.; Dunlap, Patrick H., Jr.

    1999-01-01

    Solid rockets, including the Space Shuttle solid rocket motor, are generally manufactured in large segments which are then shipped to their final destination where they are assembled. These large segments are sealed with a system of primary and secondary 0-rings to contain combustion gases inside the rocket which are at pressures of up to 900 psi and temperatures of up to 5500 F. The seals are protected from hot combustion gases by thick layers of phenolic insulation and by joint-filling compounds between these layers. Recently, though, routine inspections of nozzle-to-case joints in the Shuttle solid rocket motors during disassembly revealed erosion of the primary O-rings. Jets of hot gas leaked through gaps in the joint-filling compound between the layers of insulation and impinged on the O-rings. This is not supposed to take place, so NASA and Thiokol, the manufacturer of the rockets, initiated an investigation and found that design improvements could be made in this joint. One such improvement would involve using NASA Lewis braided thermal barriers as another level of protection for the O-ring seals against the hot combustion gases.

  18. Performance comparison of a lobed-daisy mixer nozzle with a convergent nozzle at subsonic speeds

    NASA Technical Reports Server (NTRS)

    Maiden, D. L.

    1973-01-01

    An investigation to determine the performance, in terms of thrust minus nozzle axial force, of a lobed-daisy mixer nozzle has been conducted in a 16-foot transonic tunnel at static conditions and at Mach numbers from 0.40 to 0.90 at angles of attack from 4 minus to 8. Jet-total-pressure ratio was varied from about 1.2 to 2.0. The performance of a reference convergent nozzle with a similar nozzle throat area and length was used as a base line to evaluate the performance of the lobed-daisy mixer nozzle. The results of this investigation indicate that with no external airflow (Mach number M of 0), and at values of jet-total-pressure ratio between 1.2 and 2.0, the static thrust exerted by the lobed-daisy mixer nozzle is less than that of the convergent nozzle by about 10 percent of ideal gross thrust. About 3.4 percent of the thrust loss was attributed to an unintentional internal area expansion in the fan passage.

  19. Biannular Airbreathing Nozzle Rig (BANR) facility checkout and plug nozzle performance test data

    NASA Astrophysics Data System (ADS)

    Cummings, Chase B.

    2010-09-01

    The motivation for development of a supersonic business jet (SSBJ) platform lies in its ability to create a paradigm shift in the speed and reach of commercial, private, and government travel. A full understanding of the performance capabilities of exhaust nozzle configurations intended for use in potential SSBJ propulsion systems is critical to the design of an aircraft of this type. Purdue University's newly operational Biannular Airbreathing Nozzle Rig (BANR) is a highly capable facility devoted to the testing of subscale nozzles of this type. The high accuracy, six-axis force measurement system and complementary mass flowrate measurement capabilities of the BANR facility make it rather ideally suited for exhaust nozzle performance appraisal. Detailed accounts pertaining to methods utilized in the proper checkout of these diagnostic capabilities are contained herein. Efforts to quantify uncertainties associated with critical BANR test measurements are recounted, as well. Results of a second hot-fire test campaign of a subscale Gulfstream Aerospace Corporation (GAC) axisymmetric, shrouded plug nozzle are presented. Determined test article performance parameters (nozzle thrust efficiencies and discharge coefficients) are compared to those of a previous test campaign and numerical simulations of the experimental set-up. Recently acquired data is compared to published findings pertaining to plug nozzle experiments of similar scale and operating range. Suggestions relating to the future advancement and improvement of the BANR facility are provided. Lessons learned with regards to test operations and calibration procedures are divulged in an attempt to aid future facility users, as well.

  20. Hierarchical Image Segmentation Using Correlation Clustering.

    PubMed

    Alush, Amir; Goldberger, Jacob

    2016-06-01

    In this paper, we apply efficient implementations of integer linear programming to the problem of image segmentation. The image is first grouped into superpixels and then local information is extracted for each pair of spatially adjacent superpixels. Given local scores on a map of several hundred superpixels, we use correlation clustering to find the global segmentation that is most consistent with the local evidence. We show that, although correlation clustering is known to be NP-hard, finding the exact global solution is still feasible by breaking the segmentation problem down into subproblems. Each such sub-problem can be viewed as an automatically detected image part. We can further accelerate the process by using the cutting-plane method, which provides a hierarchical structure of the segmentations. The efficiency and improved performance of the proposed method is compared to several state-of-the-art methods and demonstrated on several standard segmentation data sets. PMID:26701901

  1. Thrust vectoring effects of a transverse gas injection into a supersonic cross flow of an axisymmetric convergent-divergent nozzle

    NASA Astrophysics Data System (ADS)

    Zmijanovic, V.; Lago, V.; Leger, L.; Depussay, E.; Sellam, M.; Chpoun, A.

    2013-03-01

    The transverse gas injection into the main supersonic flow of an axisymmetric convergent-divergent (C-D) propulsive nozzle is investigated for the fluidic thrust vectoring (FTV) possibilities as the segment part of the CNES "Perseus" project. Truncated ideal contour and conical C-D nozzles with different position and angle of the secondary circular injection port are selected as test models in the current numerical and experimental study. Analytical approach revealed parameters which affect the FTV efficiency, these criterions are further numerically explored and results data of the conical nozzle test cases are compared and coupled with the ones from experiments. It is found that upstream inclined injection has positive effect on vectoring capabilities and that with moderate secondary to primary mass-flow ratios, ranging around 5%, pertinent vector side force is possible to be achieved.

  2. Measurement of gas distributions from PRS nozzles

    SciTech Connect

    Weber, B.V.; Stephanakis, S.J.; Commisso, R.J.; Fisher, A. Peterson, G.G.

    1997-05-01

    A high-sensitivity laser interferometer has been used to measure gas distributions from nozzles used in high-power plasma radiation source experiments. These measurements are important for determining experimental parameters and for modeling implosions. The integral of the gas density along the laser beam line of sight is measured as a function of time at one axial distance, z, and one radial displacement, r. The nozzle is moved to scan the (r,z) cross section. The measurements are Abel-inverted to compute the local density n(r,z,t). Several examples are shown to illustrate the technique. {copyright} {ital 1997 American Institute of Physics.}

  3. Measurement of gas distributions from PRS nozzles

    SciTech Connect

    Weber, B. V.; Stephanakis, S. J.; Commisso, R. J.; Fisher, A.; Peterson, G. G.

    1997-05-05

    A high-sensitivity laser interferometer has been used to measure gas distributions from nozzles used in high-power plasma radiation source experiments. These measurements are important for determining experimental parameters and for modeling implosions. The integral of the gas density along the laser beam line of sight is measured as a function of time at one axial distance, z, and one radial displacement, r. The nozzle is moved to scan the (r,z) cross section. The measurements are Abel-inverted to compute the local density n(r,z,t). Several examples are shown to illustrate the technique.

  4. Prototype Variable-Area Exhaust Nozzle Designed

    NASA Technical Reports Server (NTRS)

    Lee, Ho-Jun; Song, Gangbring

    2005-01-01

    Ongoing research in NASA Glenn Research Center s Structural Mechanics and Dynamics Branch to develop smart materials technologies for adaptive aeropropulsion components has resulted in the design of a prototype variable-area exhaust nozzle (see the preceding photograph). The novel design exploits the potential of smart materials to improve the performance of existing fixed-area exhaust nozzles by introducing new capabilities for adaptive shape control, vibration damping, and flow manipulation. The design utilizes two different smart materials: shape memory alloy wires as actuators and magnetorheological fluids as damper locks.

  5. Flow visualization experiments in a porous nozzle

    NASA Technical Reports Server (NTRS)

    Cielak, Z.; Kinney, R. B.; Perkins, H. C.

    1973-01-01

    An experimental approach is described for the study of nozzle flows with large wall-transpiration rates. Emphasizing a qualitative understanding of the flow, the technique uses the hydraulic analogy, whereby a compressible gas flow is simulated by a water flow having a free surface. For simplicity, the simulated gas flow is taken to be two-dimensional. A nozzle with porous walls in the throat region has been developed for use on a water table. A technique for visualizing the transpired fluid has also been devised. These are discussed, and preliminary results are presented which illustrate the success of the experimental approach.

  6. Separate Flow Nozzle Test Status Meeting

    NASA Technical Reports Server (NTRS)

    Saiyed, Naseem H. (Editor)

    2000-01-01

    NASA Glenn, in partnership with US industry, completed an exhaustive experimental study on jet noise reduction from separate flow nozzle exhaust systems. The study developed a data base on various bypass ratio nozzles, screened quietest configurations and acquired pertinent data for predicting the plume behavior and ultimately its corresponding jet noise. Several exhaust system configurations provided over 2.5 EPNdB jet noise reduction at take-off power. These data were disseminated to US aerospace industry in a conference hosted by NASA GRC whose proceedings are shown in this report.

  7. Turbocharger with variable nozzle having vane sealing surfaces

    DOEpatents

    Arnold, Philippe; Petitjean, Dominique; Ruquart, Anthony; Dupont, Guillaume; Jeckel, Denis

    2011-11-15

    A variable nozzle for a turbocharger includes a plurality of vanes rotatably mounted on a nozzle ring and disposed in a nozzle flow path defined between the nozzle ring and an opposite nozzle wall. Either or both of the faces of the nozzle ring and nozzle wall include(s) at least one step that defines sealing surfaces positioned to be substantially abutted by airfoil surfaces of the vanes in the closed position of the vanes and to be spaced from the airfoil surfaces in positions other than the closed position. This substantial abutment between the airfoil surfaces and the sealing surfaces serves to substantially prevent exhaust gas from leaking past the ends of the airfoil portions. At the same time, clearances between the nozzle ring face and the end faces of the airfoil portions can be sufficiently large to prevent binding of the vanes under all operating conditions.

  8. Linear nozzle with tailored gas plumes and method

    DOEpatents

    Leon, David D.; Kozarek, Robert L.; Mansour, Adel; Chigier, Norman

    1999-01-01

    There is claimed a method for depositing fluid material from a linear nozzle in a substantially uniform manner across and along a surface. The method includes directing gaseous medium through said nozzle to provide a gaseous stream at the nozzle exit that entrains fluid material supplied to the nozzle, said gaseous stream being provided with a velocity profile across the nozzle width that compensates for the gaseous medium's tendency to assume an axisymmetric configuration after leaving the nozzle and before reaching the surface. There is also claimed a nozzle divided into respective side-by-side zones, or preferably chambers, through which a gaseous stream can be delivered in various velocity profiles across the width of said nozzle to compensate for the tendency of this gaseous medium to assume an axisymmetric configuration.

  9. Turbulent-flow separation criteria for overexpanded supersonic nozzles

    NASA Technical Reports Server (NTRS)

    Morrisette, E. L.; Goldberg, T. J.

    1978-01-01

    A comprehensive compilation of available turbulent flow separation data for overexpanded supersonic nozzles is presented with a discussion of correlation techniques, and prediction methods. Data are grouped by nozzle types: conical, contoured, and two dimensional wedge. Correlation of conical nozzle separation is found to be independent of nozzle divergence half-angle above the 9 deg, whereas the contoured nozzle data follow a different correlation curve. Zero pressure gradient prediction techniques are shown to predict adequately the higher divergence angle conical separation data, and an empirical equation is given for the contoured nozzle data correlation. Flow conditions for which the correlations are invalid are discussed and bounded. A nozzle boundary layer transition criterion is presented which can be used to show that much of the noncorrelating data in the literature are concerned with nonturbulent separation and which explains the previously reported external flow effects on nozzle separation.

  10. Behavior of liquid metal droplets in an aspirating nozzle

    SciTech Connect

    Swank, W.D.; Fincke, J.R.; Mason, T.A.

    1990-01-01

    Measurements of particle size, velocity, and relative mass flux were made on spray field produced by aspirating liquid tin into 350{degrees}C argon flowing through a venturi nozzle via a small orifice in the throat of the nozzle. Details of the aspiration and droplet formation process were observed through windows in the nozzle. The spatial distribution of droplet size, velocity, and relative number density were measured at a location 10 mm from the nozzle exit. Due to the presence of separated flow in the nozzle, changes in nozzle inlet pressure did not significantly effect resulting droplet size and velocity. This suggests that good aerodynamic nozzle design is required if spray characteristics are to be controlled by nozzle flow. 5 refs.

  11. Behavior of liquid metal droplets in an aspirating nozzle. Revision

    SciTech Connect

    Swank, W.D.; Fincke, J.R.; Mason, T.A.

    1990-12-31

    Measurements of particle size, velocity, and relative mass flux were made on spray field produced by aspirating liquid tin into 350{degrees}C argon flowing through a venturi nozzle via a small orifice in the throat of the nozzle. Details of the aspiration and droplet formation process were observed through windows in the nozzle. The spatial distribution of droplet size, velocity, and relative number density were measured at a location 10 mm from the nozzle exit. Due to the presence of separated flow in the nozzle, changes in nozzle inlet pressure did not significantly effect resulting droplet size and velocity. This suggests that good aerodynamic nozzle design is required if spray characteristics are to be controlled by nozzle flow. 5 refs.

  12. Experience in the repair of steam generator auxiliary feedwater nozzle

    SciTech Connect

    Chao, K.K.N.

    1996-12-01

    The auxiliary feedwater nozzle is quite often subjected to more thermal stress cycles and other loading mechanisms during their service life than the material was designed and fabricated for at the nozzle of the earlier steam generators in many nuclear plants. During plant operation, the auxiliary feedwater nozzle outlet is exposed to the hot steam from the generator side, while the auxiliary feedwater piping which contains subcooled water from the inlet often induces water hammer as a result of the steam-water mixing phenomena. The thermal cycles and the steam bubble collapse at the nozzle may cause cracking in the nozzle liner and interior surface of the nozzle, and subsequently results in structural damage to the steam generator. This presentation is intended to share the lessons learned from the evaluation of the nozzle condition and the subsequent modification and repair made to the auxiliary feedwater nozzle at the Palisades Nuclear Plant. Other nuclear plant owners may benefit from this experience.

  13. F-15/nonaxisymmetric nozzle system integration study support program

    NASA Technical Reports Server (NTRS)

    Stevens, H. L.

    1978-01-01

    Nozzle and cooling methods were defined and analyzed to provide a viable system for demonstration 2-D nozzle technology on the F-15 aircraft. Two candidate cooling systems applied to each nozzle were evaluated. The F-100 engine mount and case modifications requirements were analyzed and the actuation and control system requirements for two dimensional nozzles were defined. Nozzle performance changes relative to the axisymmetric baseline nozzle were evaluated and performance and weight characteristics for axisymmetric reference configurations were estimated. The infrared radiation characteristics of these nozzles installed on the F-100 engine were predicted. A full scale development plan with associated costs to carry the F100 engine/two-dimensional (2-D) nozzle through flight tests was defined.

  14. Noise of Embedded High Aspect Ratio Nozzles

    NASA Technical Reports Server (NTRS)

    Bridges, James E.

    2011-01-01

    A family of high aspect ratio nozzles were designed to provide a parametric database of canonical embedded propulsion concepts. Nozzle throat geometries with aspect ratios of 2:1, 4:1, and 8:1 were chosen, all with convergent nozzle areas. The transition from the typical round duct to the rectangular nozzle was designed very carefully to produce a flow at the nozzle exit that was uniform and free from swirl. Once the basic rectangular nozzles were designed, external features common to embedded propulsion systems were added: extended lower lip (a.k.a. bevel, aft deck), differing sidewalls, and chevrons. For the latter detailed Reynolds-averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) simulations were made to predict the thrust performance and to optimize parameters such as bevel length, and chevron penetration and azimuthal curvature. Seventeen of these nozzles were fabricated at a scale providing a 2.13 inch diameter equivalent area throat." ! The seventeen nozzles were tested for far-field noise and a few data were presented here on the effect of aspect ratio, bevel length, and chevron count and penetration. The sound field of the 2:1 aspect ratio rectangular jet was very nearly axisymmetric, but the 4:1 and 8:1 were not, the noise on their minor axes being louder than the major axes. Adding bevel length increased the noise of these nozzles, especially on their minor axes, both toward the long and short sides of the beveled nozzle. Chevrons were only added to the 2:1 rectangular jet. Adding 4 chevrons per wide side produced some decrease at aft angles, but increased the high frequency noise at right angles to the jet flow. This trend increased with increasing chevron penetration. Doubling the number of chevrons while maintaining their penetration decreased these effects. Empirical models of the parametric effect of these nozzles were constructed and quantify the trends stated above." Because it is the objective of the Supersonics Project that

  15. SRM nozzle design breakthroughs with advanced composite materials

    NASA Astrophysics Data System (ADS)

    Berdoyes, Michel

    1993-06-01

    The weight reduction-related performance and cost of the Space Shuttle's Solid Rocket Motor (SRM) units' critical nozzle components are undergoing revolutionary improvements through the use of 3D-woven carbon/carbon and carbon/alumina composite materials. These can be used to fabricate the SRM's nozzle throat nondegradable insulators, thermostructural insulator, and exit cones. Additional developments are noted among nozzle-related structural components for additional rocket propulsion systems, including a three-piece extendible nozzle.

  16. JANNAF Rocket Nozzle Technology Subcommittee Executive Committee Report

    NASA Technical Reports Server (NTRS)

    Lawrence, Timothy W.; Munafo, Paul M. (Technical Monitor)

    2002-01-01

    This viewgraph presentation provides information on the structure and activities of the panels of the Joint Army Navy NASA Air Force (JANNAF) Rocket Nozzle Technology Subcommittee. The panels profiled are the Processing Science and Materials Panel, the Nozzle Design, Test, and Evaluation Panel, the Nozzle Analysis and Modeling Panel, and the Nozzle Control Systems Panel. The presentation also lists meetings, workshops, and publications in which the subcommittee participated during the reporting period.

  17. Characterization of hydraulic nozzles for droplet size and spray coverage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spray coverage specifications for commercially available nozzles could help applicators determine the optimal nozzles for effective control of insects, diseases and weeds. Spray coverage and deposit density from seven types of nozzles at three different flow rates (0.76, 1.14 and 2.27 l min-1) and t...

  18. Jet Nozzle Having Centerbody for Enhanced Exit Area Mixing

    NASA Technical Reports Server (NTRS)

    Seiner, John M. (Inventor); Gilinsky, Mikhail M. (Inventor)

    1999-01-01

    A nozzle arrangement includes a nozzle and a centerbody. The longitudinal axis of the centerbody is coaxially aligned with the nozzle. The centerbody has a free end portion shaped to create vortices in exhaust exiting the exit area. The vortices enhance mixing action in the exhaust and reduce exhaust noise while augmenting thrust.

  19. F100 exhaust nozzle area control

    NASA Technical Reports Server (NTRS)

    Kozlin, J. R.

    1980-01-01

    The details of the F100 nozzle mechanism design are highlighted, placing particular emphasis upon the evolution of design constraints or drivers from initial concept through current operational deployment. A kinematic description of the area control mechanism is given, and several environmental constraints which complicate the normal mechanism design process are discussed.

  20. Sluicing nozzle test report, Volume 1

    SciTech Connect

    Ramsower, D.C., Westinghouse Hanford

    1996-08-08

    The Westinghouse Hanford Company is exploring various options for retrieving waste materials from the underground storage tanks at the Hanford Site in Richland, Washington. One option under investigation is the use of a commercially available sluicing nozzle manufactured by Bristol Equipment Company.

  1. Clamp and Gas Nozzle for TIG Welding

    NASA Technical Reports Server (NTRS)

    Gue, G. B.; Goller, H. L.

    1982-01-01

    Tool that combines clamp with gas nozzle is aid to tungsten/inert-gas (TIG) welding in hard-to-reach spots. Tool holds work to be welded while directing a stream of argon gas at weld joint, providing an oxygen-free environment for tungsten-arc welding.

  2. Binary condensation in a supersonic nozzle

    SciTech Connect

    Wyslouzil, B.E.; Beals, M.G.; Wilemski, G.

    1986-12-31

    Experiments in nozzles are extremely important because they provide higher rates of cooling, higher supersaturations and higher nucleation rates than any of the other techniques. Their operating conditions are more typical of the important industrial conditions such as aerodynamic and turbomechanical flows where homogeneous nucleation can have serious consequences. Because the fluid mechanics of nozzles are well defined and understood, nucleation experiments in the nozzle are amenable to sophisticated modeling efforts and much useful insight can be gained regarding the nucleation and droplet growth processes under these severe cooling conditions. This paper summarizes recent experimental work using a gently diverging supersonic Laval nozzle to investigate all three binary pairs in the water-propanol-ethanol ternary system. Of these three binary systems, ethanol-water and propanol-water are both non-ideal and strongly influenced by surface enrichment, while ethanol-propanol should be almost ideal. The authors briefly describe the experimental apparatus and their method for preparing the binary gas mixtures. They present their experimental results and compare them to relevant experimental data and nucleation rate calculations available in the literature.

  3. Discharge Coefficients for Axisymmetric Supersonic Nozzles

    NASA Technical Reports Server (NTRS)

    Ahmad, Rashid A.; McCool, A. A. (Technical Monitor)

    2000-01-01

    Computational Fluid Dynamics (CFD) analysis was used to compute effective nozzle discharge coefficients for subscale sharp-edged converging/diverging nozzles, with a variety of convergence half-angles, motor operating conditions, and two propellants with different ballistics. Convergence half-angles ranged from 0 to 80 deg. Analysis was conducted at total temperatures from 2946K (5303R) to 3346K (6023R) and over total pressures ranged from 2.72 MPa (395 psia) to 20.68 MPa (3000 psia). Area ratios (A(sub e)/A*) ranged from 7.43 to 9.39. Ratio of specific heats (gamma) ranged from 1.13 to 1.18. Throat and exit Reynolds numbers were calculated to be 8.26 x 10(exp 5) and 5.51 x 10(exp 5), respectively. Present results of nozzle discharge coefficients are reported and correlated as a function of nozzle convergence half-angle (theta(sub c)) and area ratios (A(sub e)/A*) for a constant divergence half-angle (theta(sub d)) of 15 deg. Computed discharge coefficients ranged from 0.88 to 0.97. They are compared with theory and experimental data available in literature. Available turbulence models with respect to grid refinements and heat transfer are discussed.

  4. Low thermal stress ceramic turbine nozzle

    DOEpatents

    Glezer, B.; Bagheri, H.; Fierstein, A.R.

    1996-02-27

    A turbine nozzle vane assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and is attached to conventional metallic components, the metallic components having a preestablished rate of thermal expansion greater than the preestablished rate of thermal expansion of the turbine nozzle vane assembly. The turbine nozzle vane assembly includes an outer shroud and an inner shroud having a plurality of vanes there between. Each of the plurality of vanes have a device for heating and cooling a portion of each of the plurality of vanes. Furthermore, the inner shroud has a plurality of bosses attached thereto. A cylindrical member has a plurality of grooves formed therein and each of the plurality of bosses are positioned in corresponding ones of the plurality of grooves. The turbine nozzle vane assembly provides an economical, reliable and effective ceramic component having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the other component. 4 figs.

  5. Magnetic Nozzle and Plasma Detachment Scenario

    NASA Astrophysics Data System (ADS)

    Breizman, Boris

    2007-11-01

    Some plasma propulsion concepts rely on a strong magnetic field to guide the plasma flow through the thruster nozzle. The question then arises of how the magnetically controlled plasma can detach from the spacecraft. This talk presents a magnetohydrodynamic detachment scenario in which the plasma stretches the magnetic field lines to infinity [1]. Such a scenario is of particular interest for high-power thrusters. As plasma flows along the magnetic field lines, the originally sub-Alfv'enic flow becomes super-Alfv'enic: this transition is similar to what occurs in the solar wind [2]. In order to describe the detachment quantitatively, the ideal MHD equations have been solved analytically for a plasma flow in a slowly diverging nozzle. The solution exhibits a well-behaved transition from sub- to super- Alfv'enic flow inside the nozzle and a rarefaction wave at the edge of the outgoing flow. The magnetic field in the detached plume is almost entirely due to the plasma currents. It is shown that efficient detachment is feasible if the nozzle is sufficiently long. In order to extend the detachment model beyond the idealizations of analytical theory, a Lagrangian fluid code has been developed to solve steady-stated MHD equations and to optimize nozzle efficiency by adjusting the magnetic coil configuration. This numerical tool enables broad parameter scan with modest computational requirements (single workstation). The code has been benchmarked against the idealized analytical picture of plasma detachment and then used to investigate more realistic nozzle configurations that are not analytically tractable. Most recently, the code has been used to interpret experimental data from the Detachment Demonstration Experiment (DDEX) [3] facility at NASA Marshall Space Flight Center. In collabotation with: M. Tushentsov, A. Arefiev, R. Bengtson, J.Meyers (University of Texas at Austin), D. Chavers, C. Dobson, J. Jones (Marshall Space Flight Center), B.Schuettpelz, (University of

  6. Hydrogen/Air Fuel Nozzle Emissions Experiments

    NASA Technical Reports Server (NTRS)

    Smith, Timothy D.

    2001-01-01

    The use of hydrogen combustion for aircraft gas turbine engines provides significant opportunities to reduce harmful exhaust emissions. Hydrogen has many advantages (no CO2 production, high reaction rates, high heating value, and future availability), along with some disadvantages (high current cost of production and storage, high volume per BTU, and an unknown safety profile when in wide use). One of the primary reasons for switching to hydrogen is the elimination of CO2 emissions. Also, with hydrogen, design challenges such as fuel coking in the fuel nozzle and particulate emissions are no longer an issue. However, because it takes place at high temperatures, hydrogen-air combustion can still produce significant levels of NOx emissions. Much of the current research into conventional hydrocarbon-fueled aircraft gas turbine combustors is focused on NOx reduction methods. The Zero CO2 Emission Technology (ZCET) hydrogen combustion project will focus on meeting the Office of Aerospace Technology goal 2 within pillar one for Global Civil Aviation reducing the emissions of future aircraft by a factor of 3 within 10 years and by a factor of 5 within 25 years. Recent advances in hydrocarbon-based gas turbine combustion components have expanded the horizons for fuel nozzle development. Both new fluid designs and manufacturing technologies have led to the development of fuel nozzles that significantly reduce aircraft emissions. The goal of the ZCET program is to mesh the current technology of Lean Direct Injection and rocket injectors to provide quick mixing, low emissions, and high-performance fuel nozzle designs. An experimental program is planned to investigate the fuel nozzle concepts in a flametube test rig. Currently, a hydrogen system is being installed in cell 23 at NASA Glenn Research Center's Research Combustion Laboratory. Testing will be conducted on a variety of fuel nozzle concepts up to combustion pressures of 350 psia and inlet air temperatures of 1200 F

  7. Computational Studies of Magnetic Nozzle Performance

    NASA Technical Reports Server (NTRS)

    Ebersohn, Frans H.; Longmier, Benjamin W.; Sheehan, John P.; Shebalin, John B.; Raja, Laxminarayan

    2013-01-01

    An extensive literature review of magnetic nozzle research has been performed, examining previous work, as well as a review of fundamental principles. This has allow us to catalog all basic physical mechanisms which we believe underlie the thrust generation process. Energy conversion mechanisms include the approximate conservation of the magnetic moment adiabatic invariant, generalized hall and thermoelectric acceleration, swirl acceleration, thermal energy transformation into directed kinetic energy, and Joule heating. Momentum transfer results from the interaction of the applied magnetic field with currents induced in the plasma plume., while plasma detachment mechanisms include resistive diffusion, recombination and charge exchange collisions, magnetic reconnection, loss of adiabaticity, inertial forces, current closure, and self-field detachment. We have performed a preliminary study of Hall effects on magnetic nozzle jets with weak guiding magnetic fields and weak expansions (p(sub jet) approx. = P(sub background)). The conclusion from this study is that the Hall effect creates an azimuthal rotation of the plasma jet and, more generally, creates helical structures in the induced current, velocity field, and magnetic fields. We have studied plasma jet expansion to near vacuum without a guiding magnetic field, and are presently including a guiding magnetic field using a resistive MHD solver. This research is progressing toward the implementation of a full generalized Ohm's law solver. In our paper, we will summarize the basic principle, as well as the literature survey and briefly review our previous results. Our most recent results at the time of submittal will also be included. Efforts are currently underway to construct an experiment at the University of Michigan Plasmadynamics and Electric Propulsion Laboratory (PEPL) to study magnetic nozzle physics for a RF-thruster. Our computational study will work directly with this experiment to validate the numerical

  8. Comparison of heat transfer characteristics of a slot jet reattachment nozzle and a conventional slot jet nozzle

    SciTech Connect

    Narayanan, V.; Seyed-Yagoobi, J.; Page, R.H.

    1996-12-31

    A new type of nozzle, the Slot Jet Reattachment Nozzle (SJR), was designed and built with a zero degree exit angle. The heat transfer characteristics of the submerged SJR nozzle were compared to a conventional submerged slot jet nozzle. The comparisons were made under identical air flow power at each nozzle`s favorable height from the impinging surface. Infrared imaging techniques were used to obtain the temperature distributions on the impinging surface. The results indicate that comparable local heat transfer coefficients are obtained by the SJR nozzle while the exerted force on the impinging surface is significantly reduced. The peak local heat transfer coefficient for the SJR nozzle is approximately 8.4% higher than the peak local heat transfer coefficient for the slot jet nozzle under the same flow power. Additional experiments were conducted under matching local peak pressure for the SJR and slot jet nozzles. The results showed significant enhancements, of the order of 1.5 times, in the peak local heat transfer coefficient for the SJR nozzle over the slot jet nozzle.

  9. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR...-managing agencies on adjacent lands (both public and private)....

  10. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR...-managing agencies on adjacent lands (both public and private)....

  11. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR OFF-ROAD VEHICLE USE § 420.3 Adjacent lands. When administratively feasible, the regulation of off-road vehicle use on Reclamation lands will...

  12. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR...-managing agencies on adjacent lands (both public and private)....

  13. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR OFF-ROAD VEHICLE USE § 420.3 Adjacent lands. When administratively feasible, the regulation of...

  14. Space Shuttle Main Engine nozzle thermal protection system

    NASA Technical Reports Server (NTRS)

    Nordlund, R. M.

    1985-01-01

    Two of the three Space Shuttle Main Engine (SSME) nozzles are exposed to significant reentry aeroheating loads. To ensure reusability of the Nozzle Assembly, the nozzle primary structure must not exceed specific temperature limits. Due to the thermal, pressure, and dynamic flexing of the nozzle during a mission cycle, an appropriate insulating system must have significant flexibility. Recent missions have demonstrated nozzle reentry aeroheating rates and heat loads much higher than predictions, higher than the capability of the original insulating system. A new insulating system has been developed using similar materials in an aerodynamically 'smooth' shape to both reduce the incoming heating and increase radiation cooling.

  15. Nozzle and wing geometry effects on OTW aerodynamic characteristics

    NASA Technical Reports Server (NTRS)

    Vonglahn, U.; Groesbeck, D.

    1976-01-01

    The effects of nozzle geometry and wing size on the aerodynamic performance of several 5:1 aspect ratio slot nozzles are presented for over-the-wing (OTW) configurations. Nozzle geometry variables include roof angle, sidewall cutback, and nozzle chordwise location. Wing variables include chord size, and flap deflection. Several external deflectors also were included for comparison. The data indicate that good flow turning may not necessarily provide the best aerodynamic performance. The results suggest that a variable exhaust nozzle geometry offers the best solution for a viable OTW configuration.

  16. Some Characteristics of Fuel Sprays from Open Nozzles

    NASA Technical Reports Server (NTRS)

    Rothrock, A M; Lee, D W

    1930-01-01

    The penetration and cone-angle of fuel sprays from open nozzles were recorded with the NACA Spray Photography Equipment. The results show that for injection systems in which the rate of pressure rise at the discharge orifice is high, open nozzles give spray-tip velocities and penetrations which compare favorably with those of closed nozzles. The spray cone-angle was the same for all tests, although open nozzles having different orifice diameters were used, and one nozzle was used both as an open and as a closed nozzle. In designing a fuel system using open nozzles, particular care must be taken to avoid air pockets. The check valve should be placed close to the discharge orifice.

  17. Turbulence Measurements of Separate Flow Nozzles with Mixing Enhancement Features

    NASA Technical Reports Server (NTRS)

    Bridges, James; Wernet, Mark P.

    2002-01-01

    Comparison of turbulence data taken in three separate flow nozzles, two with mixing enhancement features on their core nozzle, shows how the mixing enhancement features modify turbulence to reduce jet noise. The three nozzles measured were the baseline axisymmetric nozzle 3BB, the alternating chevron nozzle, 3A12B, with 6-fold symmetry, and the flipper tab nozzle 3T24B also with 6-fold symmetry. The data presented show the differences in turbulence characteristics produced by the geometric differences in the nozzles, with emphasis on those characteristics of interest in jet noise. Among the significant findings: the enhanced mixing devices reduce turbulence in the jet mixing region while increasing it in the fan/core shear layer, the ratios of turbulence components are significantly altered by the mixing devices, and the integral lengthscales do not conform to any turbulence model yet proposed. These findings should provide guidance for modeling the statistical properties of turbulence to improve jet noise prediction.

  18. Low Reynolds Number Nozzle Flow Study. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Whalen, Margaret V.

    1987-01-01

    An experimental study of low Reynolds number nozzle flow was performed. A brief comparison was made between some of the experimental performance data and performance predicted by a viscous flow code. The performance of 15, 20, and 25 deg conical nozzles, bell nozzles, and trumpet nozzles was evaluated with unheated nitrogen and hydrogen. The numerical analysis was applied to the conical nozzles only, using an existing viscous flow code that was based on a slender-channel approximation. Although the trumpet and 25 deg conical nozzles had slightly better performance at lower Reynolds numbers, it is unclear which nozzle is superior as all fell within the experimental error band. The numerical rssults were found to agree with experimental results for nitrogen and for some of the hydrogen data. Some code modification is recommended to improve confidence in the performance prediction.

  19. Experimental Study of a Nozzle Using Fluidic Counterflow for Thrust Vectoring

    NASA Technical Reports Server (NTRS)

    Flamm, Jeffrey D.

    1998-01-01

    A static experimental investigation of a counterflow thrust vectoring nozzle concept was performed. The study was conducted in the NASA Langley Research Center Jet Exit Test Facility. Internal performance characteristics were defined over a nozzle pressure ratio (jet total to ambient) range of 3.5 to 10.0. The effects of suction collar geometry and suction slot height on nozzle performance were examined. In the counterflow concept, thrust vectoring is achieved by applying a vacuum to a slot adjacent to a primary jet that is shrouded by a suction collar. Two flow phenomena work to vector the primary jet depending upon the test conditions and configuration. In one case, the vacuum source creates a secondary reverse flowing stream near the primary jet. The shear layers between the two counterflowing streams mix and entrain mass from the surrounding fluid. The presence of the collar inhibits mass entrainment and the flow near the collar accelerates, causing a drop in pressure on the collar. The second case works similarly except that the vacuum is not powerful enough to create a counterflowing stream and instead a coflowing stream is present. The primary jet is vectored if suction is applied asymmetrically on the top or bottom of the jet.

  20. Development of Schlieren Imaging for Analysis of Supersonic Complex Multi-stream Rectangular Nozzle

    NASA Astrophysics Data System (ADS)

    Coleman, Thomas; Berry, Matthew; Magstadt, Andrew; Gogineni, Sivaram; Glauser, Mark; Skytop Turbulence Laboratories Team; Spectral Energies LLC. Collaboration

    2015-11-01

    A schlieren apparatus has been installed to provide the shock structure of the flow in a supersonic complex multi-stream rectangular jet nozzle. The schlieren images collected are being used for analysis which is paired with unsteady pressure data taken simultaneously, both of which complement PIV data taken in same facility. The schlieren setup is of Herschellian z-type configuration aligned vertically and perpendicular to the nozzle exit. By making use of large twin parabolic mirrors, a 12.5 inch diameter test window has been achieved, capable of capturing the evolution of shock cells from development to collapse. An LED light source was used with its driver circuit to allow for controlled microsecond pulses for collecting time resolved schlieren. Schlieren results to date indicate that there is a shock train arising inside the nozzle and persisting downstream that is quasi steady. This has also been observed in simulations. The shock structure appears to have a dominant effect in that they localize and provide the skeleton for the other flow structures, affecting and being affected by the adjacent shear layers. We would like to acknowledge SBIR Phase 2 with Spectral Energies under direction of Barry Kiel (Program Manager).

  1. Analysis of plume backflow around a nozzle lip in a nuclear rocket

    NASA Astrophysics Data System (ADS)

    Chung, Chan H.; Kim, Suk C.; Stubbs, Robert M.; de Witt, Kenneth J.

    1993-06-01

    The structure of the flow around a nuclear thermal rocket nozzle lip has been investigated using the direct simulation Monte Carlo method. Special attention has been paid to the behavior of a small amount of harmful particles that may be present in the rocket exhaust gas. The harmful fission product particles are modeled by four inert gases whose molecular weights are in a range of 4 131. Atomic hydrogen, which exists in the flow due to the extremely high nuclear fuel temperature in the reactor, is also included. It is shown that the plume backflow is primarily determined by the thin subsonic fluid layer adjacent to the surface of the nozzle lip, and that the inflow boundary in the plume region has negligible effect on the backflow. It is also shown that a relatively large amount of the lighter species is scattered into the backflow region while the amount of the heavier species becomes negligible in this region due to extreme separation between the species. Results indicate that the backscattered molecules are very energetic and are fast-moving along the surface in the backflow region near the nozzle lip.

  2. Conceptual Design Method Developed for Advanced Propulsion Nozzles

    NASA Technical Reports Server (NTRS)

    Nadell, Shari-Beth; Barnhart, Paul J.

    1998-01-01

    As part of a contract with the NASA Lewis Research Center, a simple, accurate method of predicting the performance characteristics of a nozzle design has been developed for use in conceptual design studies. The Nozzle Performance Analysis Code (NPAC) can predict the on- and off-design performance of axisymmetric or two-dimensional convergent and convergent-divergent nozzle geometries. NPAC accounts for the effects of overexpansion or underexpansion, flow divergence, wall friction, heat transfer, and small mass addition or loss across surfaces when the nozzle gross thrust and gross thrust coefficient are being computed. NPAC can be used to predict the performance of a given nozzle design or to develop a preliminary nozzle system design for subsequent analysis. The input required by NPAC consists of a simple geometry definition of the nozzle surfaces, the location of key nozzle stations (entrance, throat, exit), and the nozzle entrance flow properties. NPAC performs three analysis "passes" on the nozzle geometry. First, an isentropic control volume analysis is performed to determine the gross thrust and gross thrust coefficient of the nozzle. During the second analysis pass, the skin friction and heat transfer losses are computed. The third analysis pass couples the effects of wall shear and heat transfer with the initial internal nozzle flow solutions to produce a system of equations that is solved at steps along the nozzle geometry. Small mass additions or losses, such as those resulting from leakage or bleed flow, can be included in the model at specified geometric sections. A final correction is made to account for divergence losses that are incurred if the nozzle exit flow is not purely axial.

  3. A comprehensive segmentation analysis of crude oil market based on time irreversibility

    NASA Astrophysics Data System (ADS)

    Xia, Jianan; Shang, Pengjian; Lu, Dan; Yin, Yi

    2016-05-01

    In this paper, we perform a comprehensive entropic segmentation analysis of crude oil future prices from 1983 to 2014 which used the Jensen-Shannon divergence as the statistical distance between segments, and analyze the results from original series S and series begin at 1986 (marked as S∗) to find common segments which have same boundaries. Then we apply time irreversibility analysis of each segment to divide all segments into two groups according to their asymmetry degree. Based on the temporal distribution of the common segments and high asymmetry segments, we figure out that these two types of segments appear alternately and do not overlap basically in daily group, while the common portions are also high asymmetry segments in weekly group. In addition, the temporal distribution of the common segments is fairly close to the time of crises, wars or other events, because the hit from severe events to oil price makes these common segments quite different from their adjacent segments. The common segments can be confirmed in daily group series, or weekly group series due to the large divergence between common segments and their neighbors. While the identification of high asymmetry segments is helpful to know the segments which are not affected badly by the events and can recover to steady states automatically. Finally, we rearrange the segments by merging the connected common segments or high asymmetry segments into a segment, and conjoin the connected segments which are neither common nor high asymmetric.

  4. Energy saving opportunities of energy efficient air nozzles

    NASA Astrophysics Data System (ADS)

    Slootmaekers, Tim; Slaets, Peter; Bartsoen, Tom; Malfait, Lieven; Vanierschot, Maarten

    2015-12-01

    Compressed air is a common energy medium. The production of compressed air itself is not a very efficient process. Avoiding any unnecessary losses of air can lead to large reductions in electricity consumption. Since blowing applications are one of the main domains were compressed-air is used, any reduction in the mass flow needed for operation can lead to significant energy savings. In this paper the normal volumetric flow rate and generated impact force are compared between a stepped nozzle and a so called energy saving nozzle which allows extra air from the surroundings to be entrained. These two different nozzle geometries are used in industrial blowing applications. Until now there was no study available which compares the impact forces and volumetric flow rates for these types of nozzles. The flow field of the two nozzles was calculated by CFD simulations. The impact forces and volumetric flow rates are calculated out of this flow field. Each nozzle was simulated with three different input pressures. The nozzles were simulated with an input pressure of 3, 4 and 5 barg. The energy saving nozzle consumes only 1 % less volumetric flow rate then the stepped nozzle at the same inlet pressure. The replacement of a stepped nozzle with an energy saving nozzle will not immediately result in a decrease in input volumetric flow rate. The pressure at the inlet of the energy saving nozzle has to be reduced as well. After reducing the input pressure the energy saving nozzle generates the same impact force than the stepped nozzle. Hereby a decrease of 4.5 % in input volumetric flow rate was possible. The energy cost will decrease with 4.5 % as well because the normal volumetric flow rate is directly proportional to the energy cost. The replacement of a stepped nozzle with an energy saving nozzle while maintaining the same inlet pressure is only useful when the impact force from the stepped nozzle is not sufficient. The energy saving nozzle can generate 5.6 % more impact

  5. Computational Fluid Dynamics Simulation of Dual Bell Nozzle Film Cooling

    NASA Technical Reports Server (NTRS)

    Braman, Kalen; Garcia, Christian; Ruf, Joseph; Bui, Trong

    2015-01-01

    Marshall Space Flight Center (MSFC) and Armstrong Flight Research Center (AFRC) are working together to advance the technology readiness level (TRL) of the dual bell nozzle concept. Dual bell nozzles are a form of altitude compensating nozzle that consists of two connecting bell contours. At low altitude the nozzle flows fully in the first, relatively lower area ratio, nozzle. The nozzle flow separates from the wall at the inflection point which joins the two bell contours. This relatively low expansion results in higher nozzle efficiency during the low altitude portion of the launch. As ambient pressure decreases with increasing altitude, the nozzle flow will expand to fill the relatively large area ratio second nozzle. The larger area ratio of the second bell enables higher Isp during the high altitude and vacuum portions of the launch. Despite a long history of theoretical consideration and promise towards improving rocket performance, dual bell nozzles have yet to be developed for practical use and have seen only limited testing. One barrier to use of dual bell nozzles is the lack of control over the nozzle flow transition from the first bell to the second bell during operation. A method that this team is pursuing to enhance the controllability of the nozzle flow transition is manipulation of the film coolant that is injected near the inflection between the two bell contours. Computational fluid dynamics (CFD) analysis is being run to assess the degree of control over nozzle flow transition generated via manipulation of the film injection. A cold flow dual bell nozzle, without film coolant, was tested over a range of simulated altitudes in 2004 in MSFC's nozzle test facility. Both NASA centers have performed a series of simulations of that dual bell to validate their computational models. Those CFD results are compared to the experimental results within this paper. MSFC then proceeded to add film injection to the CFD grid of the dual bell nozzle. A series of

  6. Jet-Surface Interaction: High Aspect Ratio Nozzle Test, Nozzle Design and Preliminary Data

    NASA Technical Reports Server (NTRS)

    Brown, Clifford; Dippold, Vance

    2015-01-01

    The Jet-Surface Interaction High Aspect Ratio (JSI-HAR) nozzle test is part of an ongoing effort to measure and predict the noise created when an aircraft engine exhausts close to an airframe surface. The JSI-HAR test is focused on parameters derived from the Turbo-electric Distributed Propulsion (TeDP) concept aircraft which include a high-aspect ratio mailslot exhaust nozzle, internal septa, and an aft deck. The size and mass flow rate limits of the test rig also limited the test nozzle to a 16:1 aspect ratio, half the approximately 32:1 on the TeDP concept. Also, unlike the aircraft, the test nozzle must transition from a single round duct on the High Flow Jet Exit Rig, located in the AeroAcoustic Propulsion Laboratory at the NASA Glenn Research Center, to the rectangular shape at the nozzle exit. A parametric nozzle design method was developed to design three low noise round-to-rectangular transitions, with 8:1, 12:1, and 16: aspect ratios, that minimizes flow separations and shocks while providing a flat flow profile at the nozzle exit. These designs validated using the WIND-US CFD code. A preliminary analysis of the test data shows that the actual flow profile is close to that predicted and that the noise results appear consistent with data from previous, smaller scale, tests. The JSI-HAR test is ongoing through October 2015. The results shown in the presentation are intended to provide an overview of the test and a first look at the preliminary results.

  7. Prosodic cues enhance rule learning by changing speech segmentation mechanisms

    PubMed Central

    de Diego-Balaguer, Ruth; Rodríguez-Fornells, Antoni; Bachoud-Lévi, Anne-Catherine

    2015-01-01

    Prosody has been claimed to have a critical role in the acquisition of grammatical information from speech. The exact mechanisms by which prosodic cues enhance learning are fully unknown. Rules from language often require the extraction of non-adjacent dependencies (e.g., he plays, he sings, he speaks). It has been proposed that pauses enhance learning because they allow computing non-adjacent relations helping word segmentation by removing the need to compute adjacent computations. So far only indirect evidence from behavioral and electrophysiological measures comparing learning effects after exposure to speech with and without pauses support this claim. By recording event-related potentials during the acquisition process of artificial languages with and without pauses between words with embedded non-adjacent rules we provide direct evidence on how the presence of pauses modifies the way speech is processed during learning to enhance segmentation and rule generalization. The electrophysiological results indicate that pauses as short as 25 ms attenuated the N1 component irrespective of whether learning was possible or not. In addition, a P2 enhancement was present only when learning of non-adjacent dependencies was possible. The overall results support the claim that the simple presence of subtle pauses changed the segmentation mechanism used reflected in an exogenously driven N1 component attenuation and improving segmentation at the behavioral level. This effect can be dissociated from the endogenous P2 enhancement that is observed irrespective of the presence of pauses whenever non-adjacent dependencies are learned. PMID:26483731

  8. Advanced nozzle and engine components test facility

    NASA Technical Reports Server (NTRS)

    Beltran, Luis R.; Delroso, Richard L.; Delrosario, Ruben

    1992-01-01

    A test facility for conducting scaled advanced nozzle and engine component research is described. The CE-22 test facility, located in the Engine Research Building of the NASA Lewis Research Center, contains many systems for the economical testing of advanced scale-model nozzles and engine components. The combustion air and altitude exhaust systems are described. Combustion air can be supplied to a model up to 40 psig for primary air flow, and 40, 125, and 450 psig for secondary air flow. Altitude exhaust can be simulated up to 48,000 ft, or the exhaust can be atmospheric. Descriptions of the multiaxis thrust stand, a color schlieren flow visualization system used for qualitative flow analysis, a labyrinth flow measurement system, a data acquisition system, and auxiliary systems are discussed. Model recommended design information and temperature and pressure instrumentation recommendations are included.

  9. A nozzle internal performance prediction method

    NASA Technical Reports Server (NTRS)

    Carlson, John R.

    1992-01-01

    A prediction method was written and incorporated into a three-dimensional Navier-Stokes code (PAB3D) for the calculation of nozzle internal performance. The following quantities are calculated: (1) discharge coefficient; (2) normal, side, and axial thrust ratios; (3) rolling, pitching, and yawing moments; and (4) effective pitch and yaw vector angles. Four different case studies are presented to confirm the applicability of the methodology. Internal and, in most situations, external flow-field regions are required to be modeled. The computed nozzle discharge coefficient matches both the level and the trend of the experimental data within quoted experimental data accuracy (0.5 percent). Moment and force ratios are generally within 1 to 2 percent of the absolute level of experimental data, with the trends of data matched accurately.

  10. Solid rocket motor nozzle flexseal design sensitivity

    NASA Astrophysics Data System (ADS)

    Donat, James R.

    1993-02-01

    On solid rocket motors, direction is controlled by controlling the thrust vector. To achieve this, the nozzle usually incorporates a flexseal that allows the nozzle to vector (or rotate) in any direction. The flexseal has a core of alternating layers of elastomer pads and metal or composite shims. Flexseal core design is an iterative process. An estimate of the flexseal core geometry is made. The core is then analyzed for performance characteristics such as stress, weight, and the torque required to vector the core. Based on a comparison between the requirements/constraints and analysis results, another estimate of the geometry is then made. Understanding the effects changes in the core geometry have on the performance characteristics greatly decreases the number of iterations and time required to optimize the design. This paper documents a study undertaken to better understand these effects and how sensitive performance characteristics are to core geometry changes.

  11. Stackable multi-port gas nozzles

    DOEpatents

    Poppe, Steve; Rozenzon, Yan; Ding, Peijun

    2015-03-03

    One embodiment provides a reactor for material deposition. The reactor includes a chamber and at least one gas nozzle. The chamber includes a pair of susceptors, each having a front side and a back side. The front side mounts a number of substrates. The susceptors are positioned vertically so that the front sides of the susceptors face each other, and the vertical edges of the susceptors are in contact with each other, thereby forming a substantially enclosed narrow channel between the substrates mounted on different susceptors. The gas nozzle includes a gas-inlet component situated in the center and a detachable gas-outlet component stacked around the gas-inlet component. The gas-inlet component includes at least one opening coupled to the chamber, and is configured to inject precursor gases into the chamber. The detachable gas-outlet component includes at least one opening coupled to the chamber, and is configured to output exhaust gases from the chamber.

  12. Canard configured aircraft with 2-D nozzle

    NASA Technical Reports Server (NTRS)

    Child, R. D.; Henderson, W. P.

    1978-01-01

    A closely-coupled canard fighter with vectorable two-dimensional nozzle was designed for enhanced transonic maneuvering. The HiMAT maneuver goal of a sustained 8g turn at a free-stream Mach number of 0.9 and 30,000 feet was the primary design consideration. The aerodynamic design process was initiated with a linear theory optimization minimizing the zero percent suction drag including jet effects and refined with three-dimensional nonlinear potential flow techniques. Allowances were made for mutual interference and viscous effects. The design process to arrive at the resultant configuration is described, and the design of a powered 2-D nozzle model to be tested in the LRC 16-foot Propulsion Wind Tunnel is shown.

  13. Nozzle designs with pitch precursor ablatives

    NASA Technical Reports Server (NTRS)

    Blevins, H. R.; Bedard, R. J.

    1976-01-01

    Recent developments in carbon phenolic ablatives for solid rocket motor nozzles have yielded a pitch precursor carbon fiber offering significant raw material availability and cost saving advantages as compared to conventional rayon precursor material. This paper discusses the results of an experimental program conducted to assess the thermal performance and characterize the thermal properties of pitch precursor carbon phenolic ablatives. The end result of this program is the complete thermal characterization of pitch fabric, pitch mat, hybrid pitch/rayon fabric and pitch mat molding compound. With these properties determined an analytic capability now exists for predicting the thermal performance of these materials in rocket nozzle liner applications. Further planned efforts to verify material performance and analytical prediction procedures through actual rocket motor firings are also discussed.

  14. PDE Nozzle Optimization Using a Genetic Algorithm

    NASA Technical Reports Server (NTRS)

    Billings, Dana; Turner, James E. (Technical Monitor)

    2000-01-01

    Genetic algorithms, which simulate evolution in natural systems, have been used to find solutions to optimization problems that seem intractable to standard approaches. In this study, the feasibility of using a GA to find an optimum, fixed profile nozzle for a pulse detonation engine (PDE) is demonstrated. The objective was to maximize impulse during the detonation wave passage and blow-down phases of operation. Impulse of each profile variant was obtained by using the CFD code Mozart/2.0 to simulate the transient flow. After 7 generations, the method has identified a nozzle profile that certainly is a candidate for optimum solution. The constraints on the generality of this possible solution remain to be clarified.

  15. Stress Reduction in Adjacent Level Discs via Dynamic Instrumentation: A Finite Element Analysis

    PubMed Central

    Castellvi, Antonio E.; Huang, Hao; Vestgaarden, Tov; Saigal, Sunil; Pienkowski, David

    2007-01-01

    Background Conventional (rigid) fusion instrumentation is believed to accelerate the degeneration of adjacent discs by increasing stresses caused by motion discontinuity. Fusion instrumentation that employs reduced rod stiffness and increased axial motion, or dynamic instrumentation, may partially alleviate this problem, but the effects of this instrumentation on the stresses in the adjacent disc are unknown. We used a finiteelement model to calculate and compare the stresses in the adjacent-level disc that are induced by rigid and dynamic posterior lumbar fusion instrumentation. Methods A 3-dimensional finite-element model of the lumbar spine was obtained that simulated flexion and extension. The L5–S1 segment of this model was fused, and the L4–L5 segment was fixed with rigid or dynamic instrumentation. The mechanical properties of the dynamic instrumentation were determined by laboratory testing and then used in the finite-element model. Peak stresses in the lumbar discs were calculated and compared. Results The reduced-stiffness component of the dynamic instrumentation was associated with a 1% to 2% reduction in peak compressive stresses in the adjacent-level disc (at 45° flexion), and the increased axial motion component of this instrumentation reduced peak disc stress by 8% to 9%. Areas of disc tissue exposed to 80% of peak stresses of 6.17 MPa were 47% less for discs adjacent to dynamic instrumentation than for those adjacent to rigid instrumentation. Conclusions Reduced stiffness and increased axial motion of dynamic posterior lumbar fusion instrumentation designs result in an approximately 10% cumulative stress reduction for each flexion cycle. The effect of this stress reduction over many cycles may be substantial. Clinical Relevance The cumulative effect of this reduced amplitude and distribution of peak stresses in the adjacent disc may partially alleviate the problem of adjacent-level disc degeneration. PMID:25802582

  16. Jet Engine Exhaust Nozzle Flow Effector

    NASA Technical Reports Server (NTRS)

    Turner, Travis L. (Inventor); Cano, Roberto J. (Inventor); Silcox, Richard J. (Inventor); Buehrle, Ralph D. (Inventor); Cagle, Christopher M. (Inventor); Cabell, Randolph H. (Inventor); Hilton, George C. (Inventor)

    2011-01-01

    A jet engine exhaust nozzle flow effector is a chevron formed with a radius of curvature with surfaces of the flow effector being defined and opposing one another. At least one shape memory alloy (SMA) member is embedded in the chevron closer to one of the chevron's opposing surfaces and substantially spanning from at least a portion of the chevron's root to the chevron's tip.

  17. Wormhole Formation in RSRM Nozzle Joint Backfill

    NASA Technical Reports Server (NTRS)

    Stevens, J.

    2000-01-01

    The RSRM nozzle uses a barrier of RTV rubber upstream of the nozzle O-ring seals. Post flight inspection of the RSRM nozzle continues to reveal occurrence of "wormholes" into the RTV backfill. The term "wormholes", sometimes called "gas paths", indicates a gas flow path not caused by pre-existing voids, but by a little-understood internal failure mode of the material during motor operation. Fundamental understanding of the mechanics of the RSRM nozzle joints during motor operation, nonlinear viscoelastic characterization of the RTV backfill material, identification of the conditions that predispose the RTV to form wormholes, and screening of candidate replacement materials is being pursued by a joint effort between Thiokol Propulsion, NASA, and the Army Propulsion & Structures Directorate at Redstone Arsenal. The performance of the RTV backfill in the joint is controlled by the joint environment. Joint movement, which applies a tension and shear load on the material, coupled with the introduction of high pressure gas in combination create an environment that exceeds the capability of the material to withstand the wormhole effect. Little data exists to evaluate why the material fails under the modeled joint conditions, so an effort to characterize and evaluate the material under these conditions was undertaken. Viscoelastic property data from characterization testing will anchor structural analysis models. Data over a range of temperatures, environmental pressures, and strain rates was used to develop a nonlinear viscoelastic model to predict material performance, develop criteria for replacement materials, and quantify material properties influencing wormhole growth. Three joint simulation analogs were developed to analyze and validate joint thermal barrier (backfill) material performance. Two exploratory tests focus on detection of wormhole failure under specific motor operating conditions. A "validation" test system provides data to "validate" computer models and

  18. Jet Engine Exhaust Nozzle Flow Effector

    NASA Technical Reports Server (NTRS)

    Turner, Travis L. (Inventor); Cano, Roberto J. (Inventor); Silox, Richard J. (Inventor); Buehrle, Ralph D. (Inventor); Cagle, Christopher M. (Inventor); Cabell, Randolph H. (Inventor); Hilton, George C. (Inventor)

    2014-01-01

    A jet engine exhaust nozzle flow effector is a chevron formed with a radius of curvature with surfaces of the flow effector being defined and opposing one another. At least one shape memory alloy (SMA) member is embedded in the chevron closer to one of the chevron's opposing surfaces and substantially spanning from at least a portion of the chevron's root to the chevron's tip.

  19. Dual-bell altitude compensating nozzles

    NASA Technical Reports Server (NTRS)

    Horn, M.; Fisher, S.

    1993-01-01

    The primary objective of this cold flow test effort was to assess the performance characteristics of dual bell nozzles and to obtain preliminary design criteria by testing a number of configurations. Characteristics of interest included low altitude performance, high altitude performance, and the flow transition process. In combination with this performance data, other factors such as cost, weight, fabricability, and vehicle related issues could then be traded to establish the feasibility of the concept.

  20. Flow Separation Side Loads Excitation of Rocket Nozzle FEM

    NASA Technical Reports Server (NTRS)

    Smalley, Kurt B.; Brown, Andrew; Ruf, Joseph; Gilbert, John

    2007-01-01

    Modern rocket nozzles are designed to operate over a wide range of altitudes, and are also built with large aspect ratios to enable high efficiencies. Nozzles designed to operate over specific regions of a trajectory are being replaced in modern launch vehicles by those that are designed to operate from earth to orbit. This is happening in parallel with modern manufacturing and wall cooling techniques allowing for larger aspect ratio nozzles to be produced. Such nozzles, though operating over a large range of altitudes and ambient pressures, are typically designed for one specific altitude. Above that altitude the nozzle flow is 'underexpanded' and below that altitude, the nozzle flow is 'overexpanded'. In both conditions the nozzle produces less than the maximum possible thrust at that altitude. Usually the nozzle design altitude is well above sea level, leaving the nozzle flow in an overexpanded state for its start up as well as for its ground testing where, if it is a reusable nozzle such as the Space Shuttle Main Engine (SSME), the nozzle will operate for the majority of its life. Overexpansion in a rocket nozzle presents the critical, and sometimes design driving, problem of flow separation induced side loads. To increase their understanding of nozzle side loads, engineers at MSFC began an investigation in 2000 into the phenomenon through a task entitled "Characterization and Accurate Modeling of Rocket Engine Nozzle Side Loads", led by A. Brown. The stated objective of this study was to develop a methodology to accurately predict the character and magnitude of nozzle side loads. The study included further hot-fire testing of the MC-l engine, cold flow testing of subscale nozzles, CFD analyses of both hot-fire and cold flow nozzle testing, and finite element (fe.) analysis of the MC-1 engine and cold flow tested nozzles. A follow on task included an effort to formulate a simplified methodology for modeling a side load during a two nodal diameter fluid

  1. Oscillating combustion from a premix fuel nozzle

    SciTech Connect

    Richards, G.A.; Yip, M.J.

    1995-08-01

    Stringent emissions requirements for stationary gas turbines have produced new challenges in combustor design. In the past, very low NOx pollutant emissions have been achieved through various combustion modifications, such as steam or water injection, or post-combustion cleanup methods such as selective catalytic reduction (SCR). An emerging approach to NOx abatement is lean premix combustion. Lean premix combustion avoids the cost and operational problems associated with other NOx control methods. By premixing fuel and air at very low equivalence ratios, the high temperatures which produce NOx are avoided. The challenges of premix combustion include avoiding flashback, and ensuring adequate fuel/air premixing. In addition, the combustion must be stable. The combustor should not operate so close to extinction that a momentary upset will extinguish the flame (static stability), and the flame should not oscillate (dynamic stability). Oscillations are undesirable because the associated pressure fluctuations can shorten component lifetime. Unfortunately, experience has shown that premix fuel nozzles burning natural gas are susceptible to oscillations. Eliminating these oscillations can be a costly and time consuming part of new engine development. As part of the U.S. Department of Energy`s Advanced Turbine Systems Program, the Morgantown Energy Technology Center (METC) is investigating the issue of combustion oscillations produced by lean premix fuel nozzles. METC is evaluating various techniques to stabilize oscillating combustion in gas turbines. Tests results from a premix fuel nozzle using swirl stabilization and a pilot flame are reported here.

  2. Optimization Methodology for Unconventional Rocket Nozzle Design

    NASA Technical Reports Server (NTRS)

    Follett, W.

    1996-01-01

    Several current rocket engine concepts such as the bell-annular tripropellant engine, and the linear aerospike being proposed for the X-33, require unconventional three-dimensional rocket nozzles which must conform to rectangular or sector-shaped envelopes to meet integration constraints. These types of nozzles exist outside the current experience database, therefore, development of efficient design methods for these propulsion concepts is critical to the success of launch vehicle programs. Several approaches for optimizing rocket nozzles, including streamline tracing techniques, and the coupling of CFD analysis to optimization algorithms are described. The relative strengths and weaknesses of four classes of optimization algorithms are discussed: Gradient based methods, genetic algorithms, simplex methods, and surface response methods. Additionally, a streamline tracing technique, which provides a very computationally efficient means of defining a three-dimensional contour, is discussed. The performance of the various optimization methods on thrust optimization problems for tripropellant and aerospike concepts is assessed and recommendations are made for future development efforts.

  3. Flow Energy Piezoelectric Bimorph Nozzle Harvester

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart; Lee, Hyeong Jae; Kim, Namhyo; Sun, Kai; Corbett, Gary; Walkemeyer, Phillip; Hasenoehrl, Jennifer; Hall, Jeffery L.; Colonius, Tim; Tosi, Luis Phillipe; Arrazola, Alvaro

    2014-01-01

    There is a need for a long-life power generation scheme that could be used downhole in an oil well to produce 1 Watt average power. There are a variety of existing or proposed energy harvesting schemes that could be used in this environment but each of these has its own limitations. The vibrating piezoelectric structure is in principle capable of operating for very long lifetimes (decades) thereby possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. In order to determine the feasibility of using piezoelectrics to produce suitable flow energy harvesting, we surveyed experimentally a variety of nozzle configurations that could be used to excite a vibrating piezoelectric structure in such a way as to enable conversion of flow energy into useful amounts of electrical power. These included reed structures, spring mass-structures, drag and lift bluff bodies and a variety of nozzles with varying flow profiles. Although not an exhaustive survey we identified a spline nozzle/piezoelectric bimorph system that experimentally produced up to 3.4 mW per bimorph. This paper will discuss these results and present our initial analyses of the device using dimensional analysis and constitutive electromechanical modeling. The analysis suggests that an order-of-magnitude improvement in power generation from the current design is possible.

  4. Flow energy piezoelectric bimorph nozzle harvester

    NASA Astrophysics Data System (ADS)

    Sherrit, Stewart; Lee, Hyeong Jae; Walkemeyer, Phillip; Hasenoehrl, Jennifer; Hall, Jeffrey L.; Colonius, Tim; Tosi, Luis Phillipe; Arrazola, Alvaro; Kim, Namhyo; Sun, Kai; Corbett, Gary

    2014-04-01

    There is a need for a long-life power generation scheme that could be used downhole in an oil well to produce 1 Watt average power. There are a variety of existing or proposed energy harvesting schemes that could be used in this environment but each of these has its own limitations. The vibrating piezoelectric structure is in principle capable of operating for very long lifetimes (decades) thereby possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. In order to determine the feasibility of using piezoelectrics to produce suitable flow energy harvesting, we surveyed experimentally a variety of nozzle configurations that could be used to excite a vibrating piezoelectric structure in such a way as to enable conversion of flow energy into useful amounts of electrical power. These included reed structures, spring mass-structures, drag and lift bluff bodies and a variety of nozzles with varying flow profiles. Although not an exhaustive survey we identified a spline nozzle/piezoelectric bimorph system that experimentally produced up to 3.4 mW per bimorph. This paper will discuss these results and present our initial analyses of the device using dimensional analysis and constitutive electromechanical modeling. The analysis suggests that an order-of-magnitude improvement in power generation from the current design is possible.

  5. Nonequilibrium in a low power arcjet nozzle

    NASA Technical Reports Server (NTRS)

    Zube, Dieter M.; Myers, Roger M.

    1991-01-01

    Emission spectroscopy measurements were made of the plasma flow inside the nozzle of a 1 kW class arcjet thruster. The thruster propellant was a hydrogen-nitrogen mixture used to simulate fully decomposed hydrazine. The 0.25 mm diameter holes were drilled into the diverging section of the tungsten thruster nozzle to provide optical access to the internal flow. Atomic electron excitation, vibrational, and rotational temperatures were determined for the expanding plasma using relative line intensity techniques. The atomic excitation temperatures decreased from 18,000K at a location 3 mm downstream of the constrictor to 9,000K at a location 9 mm from the constrictor, while the molecular vibrational and rotational temperatures decreased from 6,500K to 2,500K and from 8,000K to 3,000K, respectively, between the same locations. The electron density measured using hydrogen H line Stark broadening decreased from about 10(exp 15) cm(-3) to about 2 times 10(exp 14) cm(-3) during the expansion. The results show that the plasma is highly nonequilibrium throughout the nozzle, with most relaxation times equal or exceeding the particle residence time.

  6. RSRM Nozzle Anomalous Throat Erosion Investigation Overview

    NASA Technical Reports Server (NTRS)

    Clinton, R. G., Jr.; Wendel, Gary M.

    1998-01-01

    In September, 1996, anomalous pocketing erosion was observed in the aft end of the throat ring of the nozzle of one of the reusable solid rocket motors (RSRM 56B) used on NASA's space transportation system (STS) mission 79. The RSRM throat ring is constructed of bias tape-wrapped carbon cloth/ phenolic (CCP) ablative material. A comprehensive investigation revealed necessary and sufficient conditions for occurrence of the pocketing event and provided rationale that the solid rocket motors for the subsequent mission, STS-80, were safe to fly. The nozzles of both of these motors also exhibited anomalous erosion similar to, but less extensive than that observed on STS-79. Subsequent to this flight, the investigation to identify both the specific causes and the corrective actions for elimination of the necessary and sufficient conditions for the pocketing erosion was intensified. A detailed fault tree approach was utilized to examine potential material and process contributors to the anomalous performance. The investigation involved extensive constituent and component material property testing, pedigree assessments, supplier audits, process audits, full scale processing test article fabrication and evaluation, thermal and thermostructural analyses, nondestructive evaluation, and material performance tests conducted using hot fire simulation in laboratory test beds and subscale and full scale solid rocket motor static test firings. This presentation will provide an over-view of the observed anomalous nozzle erosion and the comprehensive, fault-tree based investigation conducted to resolve this issue.

  7. A study of the transmission characteristics of suppressor nozzles

    NASA Technical Reports Server (NTRS)

    Ahuja, K. K.; Salikuddin, M.; Burrin, R. H.; Plumbee, H. E., Jr.

    1980-01-01

    The internal noise radiation characteristics for a single stream 12 lobe 24 tube suppressor nozzle, and for a dual stream 36 chute suppressor nozzle were investigated. An equivalent single round conical nozzle and an equivalent coannular nozzle system were also tested to provide a reference for the two suppressors. The technique utilized a high voltage spark discharge as a noise source within the test duct which permitted separation of the incident, reflected and transmitted signals in the time domain. These signals were then Fourier transformed to obtain the nozzle transmission coefficient and the power transfer function. These transmission parameters for the 12 lobe, 24 tube suppressor nozzle and the reference conical nozzle are presented as a function of jet Mach number, duct Mach number polar angle and temperature. Effects of simulated forward flight are also considered for this nozzle. For the dual stream, 36 chute suppressor, the transmission parameters are presented as a function of velocity ratios and temperature ratios. Possible data for the equivalent coaxial nozzle is also presented. Jet noise suppression by these nozzles is also discussed.

  8. Reusable Solid Rocket Motor - V(RSRMV)Nozzle Forward Nose Ring Thermo-Structural Modeling

    NASA Technical Reports Server (NTRS)

    Clayton, J. Louie

    2012-01-01

    During the developmental static fire program for NASAs Reusable Solid Rocket Motor-V (RSRMV), an anomalous erosion condition appeared on the nozzle Carbon Cloth Phenolic nose ring that had not been observed in the space shuttle RSRM program. There were regions of augmented erosion located on the bottom of the forward nose ring (FNR) that measured nine tenths of an inch deeper than the surrounding material. Estimates of heating conditions for the RSRMV nozzle based on limited char and erosion data indicate that the total heat loading into the FNR, for the new five segment motor, is about 40-50% higher than the baseline shuttle RSRM nozzle FNR. Fault tree analysis of the augmented erosion condition has lead to a focus on a thermomechanical response of the material that is outside the existing experience base of shuttle CCP materials for this application. This paper provides a sensitivity study of the CCP material thermo-structural response subject to the design constraints and heating conditions unique to the RSRMV Forward Nose Ring application. Modeling techniques are based on 1-D thermal and porous media calculations where in-depth interlaminar loading conditions are calculated and compared to known capabilities at elevated temperatures. Parameters such as heat rate, in-depth pressures and temperature, degree of char, associated with initiation of the mechanical removal process are quantified and compared to a baseline thermo-chemical material removal mode. Conclusions regarding postulated material loss mechanisms are offered.

  9. Study on inner hole testing of nozzle with small size and complex contour

    NASA Astrophysics Data System (ADS)

    Zhang, Liang; Su, Jun-hong; Yang, Li-hong; Xu, Jun-qi

    2010-10-01

    Testing of small size and complex contour of Nozzle, an important component affecting the engine performance, is very difficult, particularly for the inner hole. Due to difficulty in holding, it is easy to scrap the surface of the inner hole by the traditional contact-type detection methods. In this paper testing method of the hole is researched in details with image stitching technology. In the testing, a serial of focused images in different depths of inner hole of nozzle are collected by CCD camera, and compared by image focusing evaluation function, thus depth information in various locations of the inner hole images is obtained. A full depth image, the panorama of the inner hole, is rebuilt by multi-focus image fusion algorithm, for the image pixels corresponding to the focus altitudes are segmented. To achieve 3D reconstruction of the inner hole, the depth information by linear interpolation is fitted to restore a precise inner hole depth information. The results show that the inner hole of nozzle can be tested precisely with high precision which can meet the design requirements, and the entire contour can be reconstructed by the testing method.

  10. Coupled CFD-Thermal Analysis of Erosion Patterns Resulting from Nozzle Wedgeouts on the SRTMV-N2

    NASA Technical Reports Server (NTRS)

    Ables, Catherine; Davis, Philip

    2014-01-01

    The objective of this analysis was to study the effects of the erosion patterns from the introduction of nozzle flaws machined into the nozzle of the SRTMV-N2 (Solid Rocket Test Motor V Nozzle 2). The SRTMV-N2 motor was a single segment static subscale solid rocket motor used to further develop the RSRMV (Redesigned Solid Rocket Motor V Segment). Two flaws or "wedgeouts" were placed in the nozzle inlet parallel to the ply angles of that section to study erosion effects. One wedgeout was placed in the nose cap region and the other placed in the inlet ring on the opposite side of the bondline, separated 180 degrees circumferentially. A coupled CFD (Computational Fluid Analysis)-thermal iterative analytical approach was utilized at the wedgeouts to analyze the erosion profile during the burn time. The iterative CFD thermal approach was applied at five second intervals throughout the motor burn. The coupled fluid thermal boundary conditions were derived from a steady state CFD solution at the beginning of the interval. The derived heat fluxes were then applied along the surface and a transient thermal solution was developed to characterize the material response over the specified interval. Eroded profiles of each of the nozzle's wedgeouts and the original contour were created at each of the specified intervals. The final iteration of the erosion profile showed that both wedgeouts were "washedout," indicating that the erosion profile of the wedgeout had rejoined the original eroded contour, leaving no trace of the wedgeouts post fire. This analytical assessment agreed with post-fire observations made of the SRTMV-N2 wedgeouts, which noted a smooth eroded contour.

  11. Laser ablation of human atherosclerotic plaque without adjacent tissue injury

    NASA Technical Reports Server (NTRS)

    Grundfest, W. S.; Litvack, F.; Forrester, J. S.; Goldenberg, T.; Swan, H. J. C.

    1985-01-01

    Seventy samples of human cadaver atherosclerotic aorta were irradiated in vitro using a 308 nm xenon chloride excimer laser. Energy per pulse, pulse duration and frequency were varied. For comparison, 60 segments were also irradiated with an argon ion and an Nd:YAG laser operated in the continuous mode. Tissue was fixed in formalin, sectioned and examined microscopically. The Nd:YAG and argon ion-irradiated tissue exhibited a central crater with irregular edges and concentric zones of thermal and blast injury. In contrast, the excimer laser-irradiated tissue had narrow deep incisions with minimal or no thermal injury. These preliminary experiments indicate that the excimer laser vaporizes tissue in a manner different from that of the continuous wave Nd:YAG or argon ion laser. The sharp incision margins and minimal damage to adjacent normal tissue suggest that the excimer laser is more desirable for general surgical and intravascular uses than are the conventionally used medical lasers.

  12. Details of Side Load Test Data and Analysis for a Truncated Ideal Contour Nozzle and a Parabolic Contour Nozzle

    NASA Technical Reports Server (NTRS)

    Ruf, Joseph H.; McDaniels, David M.; Brown, Andrew M.

    2010-01-01

    Two cold flow subscale nozzles were tested for side load characteristics during simulated nozzle start transients. The two test article contours were a truncated ideal and a parabolic. The current paper is an extension of a 2009 AIAA JPC paper on the test results for the same two nozzle test articles. The side load moments were measured with the strain tube approach in MSFC s Nozzle Test Facility. The processing techniques implemented to convert the strain gage signals into side load moment data are explained. Nozzle wall pressure profiles for separated nozzle flow at many NPRs are presented and discussed in detail. The effect of the test cell diffuser inlet on the parabolic nozzle s wall pressure profiles for separated flow is shown. The maximum measured side load moments for the two contours are compared. The truncated ideal contour s peak side load moment was 45% of that of the parabolic contour. The calculated side load moments, via mean-plus-three-standard-deviations at each nozzle pressure ratio, reproduced the characteristics and absolute values of measured maximums for both contours. The effect of facility vibration on the measured side load moments is quantified and the effect on uncertainty is calculated. The nozzle contour designs are discussed and the impact of a minor fabrication flaw in the nozzle contours is explained.

  13. OTW noise correlation for variations in nozzle/wing geometry with 5:1 slot nozzles

    NASA Technical Reports Server (NTRS)

    Vonglahn, U.; Groesbeck, D.

    1976-01-01

    Acoustic data obtained from a model-scale study with 5:1 slot nozzles are analyzed and correlated in terms of apparent noise sources. Variations in nozzle geometry include roof angle and sidewall cutback. In addition, geometry variations in wing size and flap deflection are included. Three dominant noise sources were evident in the data and correlated: fluctuating lift noise, trailing edge noise and a redirected jet mixing noise that included the effect of reflection of jet noise by the surface. Pertinent variables in the correlations include the shear layer thickness and peak jet flow velocity at the trailing edge.

  14. Hybrid image segmentation using watersheds

    NASA Astrophysics Data System (ADS)

    Haris, Kostas; Efstratiadis, Serafim N.; Maglaveras, Nicos; Pappas, Costas

    1996-02-01

    A hybrid image segmentation algorithm is proposed which combines edge- and region-based techniques through the morphological algorithm of watersheds. The algorithm consists of the following steps: (1) edge-preserving statistical noise reduction, (2) gradient approximation, (3) detection of watersheds on gradient magnitude image, and (4) hierarchical region merging (HRM) in order to get semantically meaningful segmentations. The HRM process uses the region adjacency graph (RAG) representation of the image regions. At each step, the most similar pair of regions is determined (minimum cost RAG edge), the regions are merged and the RAG is updated. Traditionally, the above is implemented by storing all the RAG edges in a priority queue (heap). We propose a significantly faster algorithm which maintains an additional graph, the most similar neighbor graph, through which the priority queue size and processing time are drastically reduced. The final segmentation is an image partition which, through the RAG, provides information that can be used by knowledge-based high level processes, i.e. recognition. In addition, this region based representation provides one-pixel wide, closed, and accurately localized contours/surfaces. Due to the small number of free parameters, the algorithm can be quite effectively used in interactive image processing. Experimental results obtained with 2D MR images are presented.

  15. Acoustic characteristics of externally blown flap systems with mixer nozzles

    NASA Technical Reports Server (NTRS)

    Goodykoontz, J. H.; Dorsch, R. G.; Wagner, J. M.

    1974-01-01

    Noise tests were conducted on a large scale, cold flow model of an engine-under-the-wing externally blown flap lift augmentation system employing a mixer nozzle. The mixer nozzle was used to reduce the flap impingement velocity and, consequently, try to attenuate the additional noise caused by the interaction between the jet exhaust and the wing flap. Results from the mixer nozzle tests are summarized and compared with the results for a conical nozzle. The comparison showed that with the mixer nozzle, less noise was generated when the trailing flap was in a typical landing setting (e.g., 60 deg). However, for a takeoff flap setting (20 deg), there was little or no difference in the acoustic characteristics when either the mixer or conical nozzle was used.

  16. Aerodynamic performance of a transonic low aspect ratio turbine nozzle

    SciTech Connect

    Moustapha, S.H. . Turbine Aerodynamics); Carscallen, W.E. . Combustion and Fluids Engineering Lab.); McGeachy, J.D. . Dept. of Mechanical Engineering)

    1993-07-01

    This paper presents detailed information of the three-dimensional flow field in a realistic turbine nozzle with an aspect ratio of 0.65 and a turning angle of 76 deg. The nozzle has been tested in a large-scale planar cascade over a range of exit Mach numbers from 0.3 to 1.3. The experimental results are presented in the form of nozzle passage Mach number distributions and spanwise distribution of losses and exit flow angle. Details of the flow field inside the nozzle passage are examined by means of surface flow visualization and Schlieren pictures. The performance of the nozzle is compared to the data obtained for the same nozzle tested in an annular cascade and a stage environment. Excellent agreement is found between the measured pressure distribution and the prediction of a three-dimensional Euler flow solver.

  17. Star 48 solid rocket motor nozzle analyses and instrumented firings

    NASA Technical Reports Server (NTRS)

    Porter, R. L.

    1986-01-01

    The analyses and testing performed by NASA in support of an expanded and improved nozzle design data base for use by the U.S. solid rocket motor industry is presented. A production nozzle with a history of one ground failure and two flight failures was selected for analyses and testing. The stress analysis was performed with the Champion computer code developed by the U.S. Navy. Several improvements were made to the code. Strain predictions were made and compared to test data. Two short duration motor firings were conducted with highly instrumented nozzles. The first nozzle had 58 thermocouples, 66 strain gages, and 8 bondline pressure measurements. The second nozzle had 59 thermocouples, 68 strain measurements, and 8 bondline pressure measurements. Most of this instrumentation was on the nonmetallic parts, and provided significantly more thermal and strain data on the nonmetallic components of a nozzle than has been accumulated in a solid rocket motor test to date.

  18. CF6-50 Short Core Exhaust Nozzle

    NASA Technical Reports Server (NTRS)

    Dusa, D. J.; Hrach, F. J.

    1980-01-01

    The General Electric CF6-50 engine nacelle was originally equipped with both fan nozzle and core nozzle thrust reversers. Many airline operators later deactivated the core reverser. Elimination of the core reverser enabled design changes to be made to help improve performance. A reduction in core nozzle length of approximately two feet was possible. This concept, defined as the Short Core Exhaust Nozzle, was evaluated in engine ground tests, including performance, acoustic, and endurance tests under the NASA/Lewis Engine Component Improvement Program. The test results verified the performance predictions from scale model tests. The Short Core Exhaust Nozzle provides an internal cruise SFC reduction of 0.9% without an increase in engine noise. The nozzle hardware successfully completed 1000 flight cycles of endurance testing with no signs of distress.

  19. Gas turbine nozzle vane insert and methods of installation

    DOEpatents

    Miller, William John; Predmore, Daniel Ross; Placko, James Michael

    2002-01-01

    A pair of hollow elongated insert bodies are disposed in one or more of the nozzle vane cavities of a nozzle stage of a gas turbine. Each insert body has an outer wall portion with apertures for impingement-cooling of nozzle wall portions in registration with the outer wall portion. The insert bodies are installed into the cavity separately and spreaders flex the bodies toward and to engage standoffs against wall portions of the nozzle whereby the designed impingement gap between the outer wall portions of the insert bodies and the nozzle wall portions is achieved. The spreaders are secured to the inner wall portions of the insert bodies and the bodies are secured to one another and to the nozzle vane by welding or brazing.

  20. Static performance of five twin-engine nonaxisymmetric nozzles with vectoring and reversing capability

    NASA Technical Reports Server (NTRS)

    Capone, F. J.

    1978-01-01

    Transonic tunnel test was performed to determine the static performance of five twin-engine nonaxisymmetric nozzles and a base-line axisymmetric nozzle at three nozzle power settings. Static thrust-vectoring and thrust-reversing performance were also determined. Nonaxisymmetric-nozzle concepts included two-dimensional convergent-divergent nozzles, wedge nozzles, and a nozzle with a single external-expansion ramp. All nonaxisymmetric nozzles had essentially the same statis performance as the axisymmetric nozzle. Effective thrust vectoring and reversing was also achieved.

  1. Equations for the design of two-dimensional supersonic nozzles

    NASA Technical Reports Server (NTRS)

    Pinkel, I Irving

    1948-01-01

    Equations are presented for obtaining the wall coordinates of two-dimensional supersonic nozzles. The equations are based on the application of the method of characteristics to irrotational flow of perfect gases in channels. Curves and tables are included for obtaining the parameters required by the equations for the wall coordinates. A brief discussion of characteristics as applied to nozzle design is given to assist in understanding and using the nozzle-design method of this report. A sample design is shown.

  2. Fluidized-bed calciner with combustion nozzle and shroud

    DOEpatents

    Wielang, Joseph A.; Palmer, William B.; Kerr, William B.

    1977-01-01

    A nozzle employed as a burner within a fluidized bed is coaxially enclosed within a tubular shroud that extends beyond the nozzle length into the fluidized bed. The open-ended shroud portion beyond the nozzle end provides an antechamber for mixture and combustion of atomized fuel with an oxygen-containing gas. The arrangement provides improved combustion efficiency and excludes bed particles from the high-velocity, high-temperature portions of the flame to reduce particle attrition.

  3. Mounting apparatus for a nozzle guide vane assembly

    DOEpatents

    Boyd, G.L.; Shaffer, J.E.

    1995-09-12

    The present invention provides a ceramic nozzle guide assembly with an apparatus for mounting it to a metal nozzle case that includes an intermediate ceramic mounting ring. The mounting ring includes a plurality of projections that are received within a plurality of receptacles formed in the nozzle case. The projections of the mounting ring are secured within the receptacles by a ceramic retainer that allows contact between the two components only along arcuate surfaces thus eliminating sliding contact between the components. 8 figs.

  4. Mounting apparatus for a nozzle guide vane assembly

    DOEpatents

    Boyd, Gary L.; Shaffer, James E.

    1995-01-01

    The present invention provides a ceramic nozzle guide assembly with an apparatus for mounting it to a metal nozzle case that includes an intermediate ceramic mounting ring. The mounting ring includes a plurality of projections that are received within a plurality of receptacles formed in the nozzle case. The projections of the mounting ring are secured within the receptacles by a ceramic retainer that allows contact between the two components only along arcuate surfaces thus eliminating sliding contact between the components.

  5. Pressurizer with a mechanically attached surge nozzle thermal sleeve

    DOEpatents

    Wepfer, Robert M

    2014-03-25

    A thermal sleeve is mechanically attached to the bore of a surge nozzle of a pressurizer for the primary circuit of a pressurized water reactor steam generating system. The thermal sleeve is attached with a series of keys and slots which maintain the thermal sleeve centered in the nozzle while permitting thermal growth and restricting flow between the sleeve and the interior wall of the nozzle.

  6. 46 CFR 181.320 - Fire hoses and nozzles.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Fire hoses and nozzles. 181.320 Section 181.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) FIRE PROTECTION EQUIPMENT Fire Main System § 181.320 Fire hoses and nozzles. (a) A fire hose with a nozzle must be attached to each fire...

  7. An investigation of viscous losses in radial inflow turbine nozzles

    NASA Technical Reports Server (NTRS)

    Khalil, I.; Tabakoff, W.; Hamed, A.

    1977-01-01

    A theoretical model is developed to predict losses in radial inflow turbine nozzles. The analysis is presented in two parts. The first one evaluates the losses which occur across the vaned region of the nozzle, while the second part deals with the losses which take place in the vaneless field. It is concluded that the losses in a radial nozzle would not be greatly affected by the addition of a large vaneless space.

  8. Study for conceptual design of VEO, VTOL exhaust nozzle

    NASA Technical Reports Server (NTRS)

    Bittrick, W. C.

    1980-01-01

    Design requirements for a VEO Wing V/STOL exhaust nozzle with a two dimensional shape and having the capability for upper surface blowing, spanwise blowing, and 90 deg turning of the exhaust flow for VTOL were established. A preliminary design of the nozzle that identified the actuation scheme, key dimensions, the flowpath, and the recommended materials were prepared. The airplane characteristics resulting from integrating the study nozzle were established.

  9. Process modeling for carbon-phenolic nozzle materials

    NASA Technical Reports Server (NTRS)

    Letson, Mischell A.; Bunker, Robert C.; Remus, Walter M., III; Clinton, R. G.

    1989-01-01

    A thermochemical model based on the SINDA heat transfer program is developed for carbon-phenolic nozzle material processes. The model can be used to optimize cure cycles and to predict material properties based on the types of materials and the process by which these materials are used to make nozzle components. Chemical kinetic constants for Fiberite MX4926 were determined so that optimization of cure cycles for the current Space Shuttle Solid Rocket Motor nozzle rings can be determined.

  10. Fabrication, Cleaning, and Filtering of Microscopic Droplet Beam Nozzles

    NASA Astrophysics Data System (ADS)

    Warner, J.; Hunter, M.; Weierstall, U.; Spence, J. C. H.; Doak, R. B.

    2006-10-01

    Structure determination of proteins is a subject of intense current interest. Most relevant is a protein's native conformation, which generally requires it be immersed in water (if water-soluble) or a lipid jacket (if a membrane protein). Emerging schemes of serial protein diffraction propose to embed proteins in microscopic water droplets (membrane proteins encased in a detergent micelle) and pass these in vacuum through an x-ray or electron beam. Droplet diameters of <2 μm and <200 nm are dictated by the respective probe penetration depths. Rayleigh nozzles of <1 μm and <100 nm can deliver such droplets, but clogging becomes a major hurdle at nozzle diameters below even 10 μm. This talk will present an extensive study of the cleaning, filtering, and operation of 4 μm diameter nozzles with intent to minimize clogging. Borosilicate and fused silica nozzles were investigated in both commercial and self-fabricated forms. Equipment was developed to flush the nozzles from both the tip and distal ends. A variety of solvents and detergents were tested, with and without sonication and both before and after the nozzle tip was formed. Flame burnishing was employed to smooth and clean the nozzles. In situ formation of silicate filter frits was investigated. Still, only about 30% of the 4 μm nozzles would run without clogging. An alternative to solid convergent nozzles will be described.

  11. Computer program for natural gas flow through nozzles

    NASA Technical Reports Server (NTRS)

    Johnson, R. C.

    1972-01-01

    Subroutines, FORTRAN 4 type, were developed for calculating isentropic natural gas mass flow rate through nozzle. Thermodynamic functions covering compressibility, entropy, enthalpy, and specific heat are included.

  12. Erosion resistant nozzles for laser plasma extreme ultraviolet (EUV) sources

    DOEpatents

    Kubiak, Glenn D.; Bernardez, II, Luis J.

    2000-01-04

    A gas nozzle having an increased resistance to erosion from energetic plasma particles generated by laser plasma sources. By reducing the area of the plasma-facing portion of the nozzle below a critical dimension and fabricating the nozzle from a material that has a high EUV transmission as well as a low sputtering coefficient such as Be, C, or Si, it has been shown that a significant reduction in reflectance loss of nearby optical components can be achieved even after exposing the nozzle to at least 10.sup.7 Xe plasma pulses.

  13. Performance Characteristics of the Methane Fueled Rocket Nozzles

    NASA Astrophysics Data System (ADS)

    Ito, Takashi; Miyajima, Hiroshi

    Performance of the methane fueled rocket nozzles are numerically investigated using computational fluid dynamics approach. A simple set of chemical reactions and kinetics for methane/oxygen nozzle flow is proposed. The chamber pressure, mixture ratio and size of the nozzle are parametrically changed to study the influence of characteristic rocket engine design parameters on nozzle losses. The amount of dissociation is high when the chamber pressure is low and the kinetic loss becomes dominant compared to the other nozzle losses. The peak specific impulse is achieved at a higher mixture ratio region as the chamber pressure increases. The chemical non-equilibrium flow appears mainly at down stream region of the nozzle throat. The influence of the chemical non-equilibrium effect decreases as the chamber pressure increases. Supersonic chemically reactive gas stays longer in the nozzle as the size of the nozzle become larger and the amount of recombination increases which decreases the kinetic loss. When the chamber pressure is high, the kinetic loss becomes small and the effect of the size of nozzle also becomes small.

  14. Evaluation of nozzle shapes for an optical flow meter

    NASA Astrophysics Data System (ADS)

    Sheikholeslami, M. Z.; Patel, B. R.

    1992-05-01

    Numerical modeling is performed for turbulent flow in axisymmetric nozzles using Creare's computer program FLUENT/BFC. The primary objective of the project was to assist Spectron Development Laboratories in selecting an optimum nozzle shape for an optical flowmeter. The nozzle performance is evaluated for various length to diameter ratios, area contraction ratios, and Reynolds numbers. The computations have demonstrated that a cubic profile nozzle with length to diameter ratio of 1.6 and area contraction ratio of 6.2 can decrease the velocity profile non-uniformity from 15 percent at the entrance to 1 percent at the exit. The configuration is recommended for further investigation.

  15. Analysis of Nozzle Jet Plume Effects on Sonic Boom Signature

    NASA Technical Reports Server (NTRS)

    Bui, Trong

    2010-01-01

    An axisymmetric full Navier-Stokes computational fluid dynamics (CFD) study was conducted to examine nozzle exhaust jet plume effects on the sonic boom signature of a supersonic aircraft. A simplified axisymmetric nozzle geometry, representative of the nozzle on the NASA Dryden NF-15B Lift and Nozzle Change Effects on Tail Shock (LaNCETS) research airplane, was considered. The highly underexpanded nozzle flow is found to provide significantly more reduction in the tail shock strength in the sonic boom N-wave pressure signature than perfectly expanded and overexpanded nozzle flows. A tail shock train in the sonic boom signature, similar to what was observed in the LaNCETS flight data, is observed for the highly underexpanded nozzle flow. The CFD results provide a detailed description of the nozzle flow physics involved in the LaNCETS nozzle at different nozzle expansion conditions and help in interpreting LaNCETS flight data as well as in the eventual CFD analysis of a full LaNCETS aircraft. The current study also provided important information on proper modeling of the LaNCETS aircraft nozzle. The primary objective of the current CFD research effort was to support the LaNCETS flight research data analysis effort by studying the detailed nozzle exhaust jet plume s imperfect expansion effects on the sonic boom signature of a supersonic aircraft. Figure 1 illustrates the primary flow physics present in the interaction between the exhaust jet plume shock and the sonic boom coming off of an axisymmetric body in supersonic flight. The steeper tail shock from highly expanded jet plume reduces the dip of the sonic boom N-wave signature. A structured finite-volume compressible full Navier-Stokes CFD code was used in the current study. This approach is not limited by the simplifying assumptions inherent in previous sonic boom analysis efforts. Also, this study was the first known jet plume sonic boom CFD study in which the full viscous nozzle flow field was modeled, without

  16. Noise Benefits of Increased Fan Bypass Nozzle Area

    NASA Technical Reports Server (NTRS)

    Woodward, Richard P.; Hughes, Christopher E.

    2004-01-01

    An advanced model turbofan (typical of current engine technology) was tested in the NASA Glenn 9 by 15 Foot Low Speed Wind Tunnel (9-by 15-Foot LSWT) to explore far field acoustic effects of increased bypass nozzle area. This fan stage test was part of the NASA Glenn Fan Broadband Source Diagnostic Test, second entry (SDT2) which acquired aeroacoustic results over a range of test conditions. The baseline nozzle was sized to produce maximum stage performance for the engine at a high altitude, cruise point condition. However, the wind tunnel testing is conducted near sea level conditions. Therefore, in order to simulate and obtain performance at other aircraft operating conditions, two additional nozzles were designed and tested-one with a +5 percent increase in weight flow (+5.4 percent increase in nozzle area compared with the baseline nozzle), sized to simulate the performance at the stage design point conditions, and the other with a +7.5 percent increase in weight flow (+10.9 percent increase in nozzle area), sized for maximum weight flow with a fixed nozzle at sea level conditions. Measured acoustic benefits with increased nozzle area were very encouraging, showing overall sound power level (OAPWL) reductions of 2 or more dB while the stage thrust actually increased by several percentage points except fro the most open nozzle at takeoff rotor speed where stage performance decreased. These noise reduction benefits were seen to primarily affect broadband noise, and were evident throughout the range of measured sideline angles.

  17. Water distribution characteristics of spray nozzles in a cooling tower

    NASA Astrophysics Data System (ADS)

    Vitkovic, Pavol

    2015-05-01

    Water distribution characteristics of spray nozzles with spray plates used to distribute cooling water to the cooling fills in a cooling tower is one of the important parameters for the selection of nozzles. Water distribution characteristic describes the distribution of water from the axis of the nozzle along a fill. One of the parameters affecting the water distribution characteristic of the nozzle is airflow velocity of counter flow airstream. Water distribution characteristics are commonly measured using by a set of containers. The problem with this method of the measurement of characteristics is block of the airflow with collections of containers. Therefore, this work is using the visualization method.

  18. Flow separation in rocket nozzles under high altitude condition

    NASA Astrophysics Data System (ADS)

    Stark, R.; Génin, C.

    2016-03-01

    The knowledge of flow separation in rocket nozzles is crucial for rocket engine design and optimum performance. Typically, flow separation is studied under sea-level conditions. However, this disregards the change of the ambient density during ascent of a launcher. The ambient flow properties are an important factor concerning the design of altitude-adaptive rocket nozzles like the dual bell nozzle. For this reason an experimental study was carried out to study the influence of the ambient density on flow separation within conventional nozzles.

  19. TMI-2 instrument nozzle examinations at Argonne National Laboratory, February 1991--June 1993

    SciTech Connect

    Neimark, L.A.; Shearer, T.L.; Purohit, A.; Hins, A.G.

    1994-06-01

    The accident at the Three Mile Island Unit 2 (TMI-2) reactor in March 1979 resulted in the relocation of approximately 19,000 kg of molten core material to the lower head of the reactor vessel. This material caused extensive damage to the instrument guide tubes and nozzles and was suspected of having caused significant metallurgical changes in the condition of the lower head itself. These changes and their effect on the margin-to-failure of the lower head became the focal point of an investigation co-sponsored by the United States Nuclear Regulatory Commission (NRC) and the Organization for Economic Co-operation and Development (OECD). The TMI-2 Vessel Investigation Project (VIP) was formed to determine the metallurgical state of the vessel at the lower head and to assess the margin-to-failure of the vessel under the conditions existing during the accident. This report was prepared under the auspices of the OECD/NEA Three Mile Island Vessel Investigation Project. Under the auspices of the VIP, specimens of the reactor vessel were removed in February 1990 by MPR Associates, Inc. In addition to these specimens, fourteen instrument nozzle segments and two segments of instrument guide tubes were retrieved for metallurgical evaluation. The purpose of this evaluation was to provide additional information on the thermal conditions on the lower head that would influence the margin-to-failure, and to provide insight into the progression of the accident scenario, specifically the movement of the molten fuel across the lower head.

  20. Coaxial nozzle-assisted 3D bioprinting with built-in microchannels for nutrients delivery.

    PubMed

    Gao, Qing; He, Yong; Fu, Jian-zhong; Liu, An; Ma, Liang

    2015-08-01

    This study offers a novel 3D bioprinting method based on hollow calcium alginate filaments by using a coaxial nozzle, in which high strength cell-laden hydrogel 3D structures with built-in microchannels can be fabricated by controlling the crosslinking time to realize fusion of adjacent hollow filaments. A 3D bioprinting system with a Z-shape platform was used to realize layer-by-layer fabrication of cell-laden hydrogel structures. Curving, straight, stretched or fractured filaments can be formed by changes to the filament extrusion speed or the platform movement speed. To print a 3D structure, we first adjusted the concentration and flow rate of the sodium alginate and calcium chloride solution in the crosslinking process to get partially crosslinked filaments. Next, a motorized XY stages with the coaxial nozzle attached was used to control adjacent hollow filament deposition in the precise location for fusion. Then the Z stage attached with a Z-shape platform moved down sequentially to print layers of structure. And the printing process always kept the top two layers fusing and the below layers solidifying. Finally, the Z stage moved down to keep the printed structure immersed in the CaCl2 solution for complete crosslinking. The mechanical properties of the resulting fused structures were investigated. High-strength structures can be formed using higher concentrations of sodium alginate solution with smaller distance between adjacent hollow filaments. In addition, cell viability of this method was investigated, and the findings show that the viability of L929 mouse fibroblasts in the hollow constructs was higher than that in alginate structures without built-in microchannels. Compared with other bioprinting methods, this study is an important technique to allow easy fabrication of lager-scale organs with built-in microchannels. PMID:26004235

  1. On the time-course of adjacent and non-adjacent transposed-letter priming

    PubMed Central

    Ktori, Maria; Kingma, Brechtsje; Hannagan, Thomas; Holcomb, Phillip J.; Grainger, Jonathan

    2014-01-01

    We compared effects of adjacent (e.g., atricle-ARTICLE) and non-adjacent (e.g., actirle-ARTICLE) transposed-letter (TL) primes in an ERP study using the sandwich priming technique. TL priming was measured relative to the standard double-substitution condition. We found significantly stronger priming effects for adjacent transpositions than non-adjacent transpositions (with 2 intervening letters) in behavioral responses (lexical decision latencies), and the adjacent priming effects emerged earlier in the ERP signal, at around 200 ms post-target onset. Non-adjacent priming effects emerged about 50 ms later and were short-lived, being significant only in the 250-300 ms time-window. Adjacent transpositions on the other hand continued to produce priming in the N400 time-window (300-500 ms post-target onset). This qualitatively different pattern of priming effects for adjacent and non-adjacent transpositions is discussed in the light of different accounts of letter transposition effects, and the utility of drawing a distinction between positional flexibility and positional noise. PMID:25364497

  2. Exit chimney joint and method of forming the joint for closed circuit steam cooled gas turbine nozzles

    DOEpatents

    Burdgick, Steven Sebastian; Burns, James Lee

    2002-01-01

    A nozzle segment for a gas turbine includes inner and outer band portions and a vane extending between the band portions. The inner and outer band portions are each divided into first and second plenums separated by an impingement plate. Cooling steam is supplied to the first cavity for flow through the apertures to cool the outer nozzle wall. The steam flows through a leading edge cavity in the vane into the first cavity of the inner band portion for flow through apertures of the impingement plate to cool the inner nozzle wall. Spent cooling steam flows through a plurality of cavities in the vane, exiting through an exit chimney in the outer band. The exit chimney is secured at its inner end directly to the nozzle vane wall surrounding the exit cavities, to the margin of the impingement plate at a location intermediate the ends of the exit chimney and to margins of an opening through the cover whereby each joint is externally accessible for joint formation and for subsequent inspection.

  3. Critical Propulsion Components. Volume 3; Exhaust Nozzle

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Several studies have concluded that a supersonic aircraft, if environmentally acceptable and economically viable, could successfully compete in the 21st century marketplace. However, before industry can commit to what is estimated as a 15 to 20 billion dollar investment, several barrier issues must be resolved. In an effort to address these barrier issues, NASA and Industry teamed to form the High-Speed Research (HSR) program. As part of this program, the Critical Propulsion Components (CPC) element was created and assigned the task of developing those propulsion component technologies necessary to: (1) reduce cruise emissions by a factor of 10 and (2) meet the ever-increasing airport noise restrictions with an economically viable propulsion system. The CPC-identified critical components were ultra-low emission combustors, low-noise/high-performance exhaust nozzles, low-noise fans, and stable/high-performance inlets. Propulsion cycle studies (coordinated with NASA Langley Research Center sponsored airplane studies) were conducted throughout this CPC program to help evaluate candidate components and select the best concepts for the more complex and larger scale research efforts. The propulsion cycle and components ultimately selected were a mixed-flow turbofan (MFTF) engine employing a lean, premixed, prevaporized (LPP) combustor coupled to a two-dimensional mixed compression inlet and a two-dimensional mixer/ejector nozzle. Due to the large amount of material presented in this report, it was prepared in four volumes; Volume 1: Summary, Introduction, and Propulsion System Studies, Volume 2: Combustor, Volume 3: Exhaust Nozzle, and Volume 4: Inlet and Fan/Inlet Acoustic Team.

  4. On the Theory of the Laval Nozzle

    NASA Technical Reports Server (NTRS)

    Falkovich, S. V.

    1949-01-01

    In the present paper, the motion of a gas in a plane-parallel Laval nozzle in the neighborhood of the transition from subsonic to supersonic velocities is studied. In a recently published paper, F. I. Frankl, applying the holograph method of Chaplygin, undertook a detailed investigation of the character of the flow near the line of transition from subsonic to supersonic velocities. From the results of Tricomi's investigation on the theory of differential equations of the mixed elliptic-hyperbolic type, Frankl introduced as one of the independent variables in place of the modulus of the velocity, a certain specially chosen function of this modulus. He thereby succeeded in explaining the character of the flow at the point of intersection of the transition line and the axis of symmetry (center of the nozzle) and in studying the behavior of the stream function in the neighborhood of this point by separating out the principal term having, together with its derivatives, the maximum value as compared with the corresponding corrections. This principal term is represented in Frankl's paper in the form of a linear combination of two hypergeometric functions. In order to find this linear combination, it is necessary to solve a number of boundary problems, which results in a complex analysis. In the investigation of the flow with which this paper is concerned, a second method is applied. This method is based on the transformation of the equations of motion to a form that may be called canonical for the system of differential equations of the mixed elliptic-hyperbolic type to which the system of equations of the motion of an ideal compressible fluid refers. By studying the behavior of the integrals of this system in the neighborhood of the parabolic line, the principal term of the solution is easily separated out in the form of a polynomial of the third degree. As a result, the computation of the transitional part of the nozzle is considerably simplified.

  5. BWR feedwater nozzle and control-rod-drive return line nozzle cracking

    SciTech Connect

    Not Available

    1981-11-01

    In its 1978 Annual Report to Congress, the Nuclear Regulatory Commission identified as an unresolved safety issue the appearance of cracks in feedwater nozzles at boiling-water reactors (BWRs). Later similar cracking, detected in return water lines for control-rod-drive systems at BWRs, was designated Part II of the issue. This article outlines the resolution of these cracking problems.

  6. Airfoil shape for a turbine nozzle

    SciTech Connect

    Burdgick, Steven Sebastian; Patik, Joseph Francis; Itzel, Gary Michael

    2002-01-01

    A first-stage nozzle vane includes an airfoil having a profile according to Table I. The annulus profile of the hot gas path is defined in conjunction with the airfoil profile and the profile of the inner and outer walls by the Cartesian coordinate values given in Tables I and II, respectively. The airfoil is a three-dimensional bowed design, both in the airfoil body and in the trailing edge. The airfoil is steam and air-cooled by flowing cooling mediums through cavities extending in the vane between inner and outer walls.

  7. NASA/MSFC nozzle test bed

    NASA Technical Reports Server (NTRS)

    Crose, James G.; Mack, Thomas E.; Marx, Douglas A.; Goldberg, Benjamin; Shrader, John E.

    1989-01-01

    As part of an effort to improve the state-of-the-art in nozzle technology, a solid propulsion test bed facility is being designed and will be located at Marshall Space Flight Center. The test bed will consist of a plasma arc facility and several small scale rocket motor test facilities ranging in size from the ballistic environmental generator motor with a 1/2 in. diameter throat to the MNASA motor with a 9 and 1/2 in. diameter throat capability. The test bed system will be used primarily to study materials behavior from the standpoint of char, erosion, and thermal stress phenomena.

  8. Mach disk from underexpanded axisymmetric nozzle flow

    NASA Technical Reports Server (NTRS)

    Chang, I.-S.; Chow, W. L.

    1974-01-01

    The flowfield associated with the underexpanded axisymmetric nozzle freejet flow including the appearance of a Mach disk has been studied. It is shown that the location and size of the Mach disk are governed by the appearance of a triple-point shock configuration and the condition that the central core flow will reach a state of 'choking at a throat'. It is recognized that coalescence of waves requires special attention and the reflected wave, as well as the vorticity generated from these wave interactions, have to be taken accurately into account. The theoretical results obtained agreed well with the experimental data.

  9. Transonic potential flow in hyperbolic nozzles

    NASA Technical Reports Server (NTRS)

    Park, M.; Caughey, D. A.

    1986-01-01

    The full potential equation for the classical problem of transonic flow through a hyperbolic nozzle (with or without a shock wave) is solved in conservation form using the finite volume method of Jameson and Caughey (1977). Either a firstor a second-order numerical viscosity is added in the direction of the flow, explicitly, in conservation form. A multigrid alternating direction implicit method is used to solve the difference equations, and the results obtained are compared with analytical and numerical results from previous researches.

  10. A Class of De Laval Nozzles

    NASA Technical Reports Server (NTRS)

    Falkovich, S. V.

    1949-01-01

    A study is made herein of the irrotational adiabatic motion of a gas in the transition from subsonic to supersonic velocities. A shape of the de Laval nozzle is given, which transforms a homogeneous plane-parallel flow at large subsonic velocity into a supersonic flow without any shockwaves beyond the transition line from the subsonic to the supersonic regions of flow. The method of solution is based on integration near the transition line of the gas equations of motion in the form investigated by S. A. Christianovich.

  11. Segment alignment control system

    NASA Technical Reports Server (NTRS)

    Aubrun, JEAN-N.; Lorell, Ken R.

    1988-01-01

    The segmented primary mirror for the LDR will require a special segment alignment control system to precisely control the orientation of each of the segments so that the resulting composite reflector behaves like a monolith. The W.M. Keck Ten Meter Telescope will utilize a primary mirror made up of 36 actively controlled segments. Thus the primary mirror and its segment alignment control system are directly analogous to the LDR. The problems of controlling the segments in the face of disturbances and control/structures interaction, as analyzed for the TMT, are virtually identical to those for the LDR. The two systems are briefly compared.

  12. Effect of magnetic and physical nozzles on plasma thruster performance

    NASA Astrophysics Data System (ADS)

    Takahashi, Kazunori; Charles, Christine; Boswell, Rod; Ando, Akira

    2014-08-01

    Plasma cross-field diffusion in a magnetic nozzle is inhibited by increasing the magnetic field strength in a helicon plasma thruster attached to a pendulum thrust balance, while maintaining constant plasma density and electron temperature in the source tube, i.e. a constant plasma injection into the magnetic nozzle, where the field strength near the radio frequency (rf) antenna is less than 210 G and the operating argon pressure in the vacuum chamber is 0.8 mTorr. Inhibition of the cross-field diffusion yields a higher electron pressure in the magnetic nozzle and a resultant larger thrust. The thrust component arising from the magnetic nozzle approaches the theoretical limit derived from an ideal magnetic nozzle approximation where no plasma is lost from the nozzle and there is an azimuthal plasma current originating from the electron diamagnetic drift. It is also shown that the momentum of the plasma lost from the magnetic nozzle is captured by a physical nozzle attached at the source exit resulting in a larger thrust. Two physical nozzles of different sizes (nozzle 1 : 10.5 cm in length with a maximum diameter of 20 cm, nozzle 2 : 26 cm in length with a maximum diameter of 36 cm) are tested. The maximum thrust of 20 ± 1 mN is obtained for 25 sccm argon propellant and 2 kW rf power with a reflection power less than 5 W, which gives a specific impulse of 2750 ± 165 s and a thrust efficiency of 13.5 ± 1.5%.

  13. PROPAGATION AND LINKAGE OF OCEANIC RIDGE SEGMENTS.

    USGS Publications Warehouse

    Pollard, David D.; Aydin, Atilla

    1984-01-01

    An investigation was made of spreading ridges and the development of structures that link ridge segments using an analogy between ridges and cracks in elastic plates. The ridge-propagation force and a path factor that controls propagation direction were calculated for echelon ridge segments propagating toward each other. The ridge-propagation force increases as ridge ends approach but then declines sharply as the ends pass, so ridge segments may overlap somewhat. The sign of the path factor changes as ridge ends approach and pass, so the overlapping ridge ends may diverge and then converge following a hook-shaped path. The magnitudes of shear stresses in the plane of the plate and orientations of maximum shear planes between adjacent ridge segments were calculated to study transform faulting. For different loading conditions simulating ridge push, plate pull, and ridge suction, a zone of intense mechanical interaction between adjacent ridge ends in which stresses are concentrated was identified. The magnitudes of mean stresses in the plane of the plate and orientations of principal stress planes were also calculated.

  14. Air assist fuel nozzle reduces aircraft gas turbine engine emissions at idle operation

    NASA Technical Reports Server (NTRS)

    Briehl, D.; Papathakos, L. C.

    1972-01-01

    Reduction in unburned hydrocarbons from jet engine by use of air assist fuel nozzle is discussed. Operation of nozzle for improving combustion efficiency by improving fuel atomization is analyzed. Advantages to be achieved by air assist fuel nozzle are analyzed.

  15. Magnetic Interface for Segmented Mirror Assembly

    NASA Technical Reports Server (NTRS)

    Stahl, H.

    2012-01-01

    Newly developed magnetic devices are used to create an interface between adjacent mirror segments so that once assembled, aligned, and phased, the multiple segments will behave functionally equivalent to a monolithic aperture mirror. One embodiment might be a kinematic interface that is reversible so that any number of segments can be pre-assembled, aligned, and phased to facilitate fabrication operations, and then disassembled and reassembled, aligned, and phased in space for operation. The interface mechanism has sufficient stiffness, force, and stability to maintain phasing. The key to producing an interface is the correlated magnetic surface. While conventional magnets are only constrained in one direction -- the direction defined by their point of contact (they are in contact and cannot get any closer) -- correlated magnets can be designed to have constraints in multiple degrees of freedom. Additionally, correlated magnetic surfaces can be designed to have a limited range of action.

  16. Fault Diagnostics and Prognostics for Large Segmented SRMs

    NASA Technical Reports Server (NTRS)

    Luchinsky, Dmitry; Osipov, Viatcheslav V.; Smelyanskiy, Vadim N.; Timucin, Dogan A.; Uckun, Serdar; Hayashida, Ben; Watson, Michael; McMillin, Joshua; Shook, David; Johnson, Mont; Hyde, Scott

    2009-01-01

    We report progress in development of the fault diagnostic and prognostic (FD&P) system for large segmented solid rocket motors (SRMs). The model includes the following main components: (i) 1D dynamical model of internal ballistics of SRMs; (ii) surface regression model for the propellant taking into account erosive burning; (iii) model of the propellant geometry; (iv) model of the nozzle ablation; (v) model of a hole burning through in the SRM steel case. The model is verified by comparison of the spatially resolved time traces of the flow parameters obtained in simulations with the results of the simulations obtained using high-fidelity 2D FLUENT model (developed by the third party). To develop FD&P system of a case breach fault for a large segmented rocket we notice [1] that the stationary zero-dimensional approximation for the nozzle stagnation pressure is surprisingly accurate even when stagnation pressure varies significantly in time during burning tail-off. This was also found to be true for the case breach fault [2]. These results allow us to use the FD&P developed in our earlier research [3]-[6] by substituting head stagnation pressure with nozzle stagnation pressure. The axial corrections to the value of the side thrust due to the mass addition are taken into account by solving a system of ODEs in spatial dimension.

  17. Magnetic Nozzle and Plasma Detachment Experiment

    NASA Technical Reports Server (NTRS)

    Chavers, Gregory; Dobson, Chris; Jones, Jonathan; Martin, Adam; Bengtson, Roger D.; Briezman, Boris; Arefiev, Alexey; Cassibry, Jason; Shuttpelz, Branwen; Deline, Christopher

    2006-01-01

    High power plasma propulsion can move large payloads for orbit transfer (such as the ISS), lunar missions, and beyond with large savings in fuel consumption owing to the high specific impulse. At high power, lifetime of the thruster becomes an issue. Electrodeless devices with magnetically guided plasma offer the advantage of long life since magnetic fields confine the plasma radially and keep it from impacting the material surfaces. For decades, concerns have been raised about the plasma remaining attached to the magnetic field and returning to the vehicle along the closed magnetic field lines. Recent analysis suggests that this may not be an issue of the magnetic field is properly shaped in the nozzle region and the plasma has sufficient energy density to stretch the magnetic field downstream. An experiment was performed to test the theory regarding the Magneto-hydrodynamic (MHD) detachment scenario. Data from this experiment will be presented. The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) being developed by the Ad Astra Rocket Company uses a magnetic nozzle as described above. The VASIMR is also a leading candidate for exploiting an electric propulsion test platform being considered for the ISS.

  18. Simulating radiative shocks in nozzle shock tubes

    NASA Astrophysics Data System (ADS)

    van der Holst, B.; Tóth, G.; Sokolov, I. V.; Daldorff, L. K. S.; Powell, K. G.; Drake, R. P.

    2012-06-01

    We use the recently developed Center for Radiative Shock Hydrodynamics (CRASH) code to numerically simulate laser-driven radiative shock experiments. These shocks are launched by an ablated beryllium disk and are driven down xenon-filled plastic tubes. The simulations are initialized by the two-dimensional version of the Lagrangian Hyades code which is used to evaluate the laser energy deposition during the first 1.1 ns. Later times are calculated with the CRASH code. CRASH solves for the multi-material hydrodynamics with separate electron and ion temperatures on an Eulerian block-adaptive-mesh and includes a multi-group flux-limited radiation diffusion and electron thermal heat conduction. The goal of the present paper is to demonstrate the capability to simulate radiative shocks of essentially three-dimensional experimental configurations, such as circular and elliptical nozzles. We show that the compound shock structure of the primary and wall shock is captured and verify that the shock properties are consistent with order-of-magnitude estimates. The synthetic radiographs produced can be used for comparison with future nozzle experiments at high-energy-density laser facilities.

  19. Analysis of film cooling in rocket nozzles

    NASA Technical Reports Server (NTRS)

    Woodbury, Keith A.

    1993-01-01

    This report summarizes the findings on the NASA contract NAG8-212, Task No. 3. The overall project consists of three tasks, all of which have been successfully completed. In addition, some supporting supplemental work, not required by the contract, has been performed and is documented herein. Task 1 involved the modification of the wall functions in the code FDNS (Finite Difference Navier-Stokes) to use a Reynolds Analogy-based method. This task was completed in August, 1992. Task 2 involved the verification of the code against experimentally available data. The data chosen for comparison was from an experiment involving the injection of helium from a wall jet. Results obtained in completing this task also show the sensitivity of the FDNS code to unknown conditions at the injection slot. This task was completed in September, 1992. Task 3 required the computation of the flow of hot exhaust gases through the P&W 40K subscale nozzle. Computations were performed both with and without film coolant injection. This task was completed in July, 1993. The FDNS program tends to overpredict heat fluxes, but, with suitable modeling of backside cooling, may give reasonable wall temperature predictions. For film cooling in the P&W 40K calorimeter subscale nozzle, the average wall temperature is reduced from 1750R to about 1050R by the film cooling. The average wall heat flux is reduced by a factor of 3.

  20. Min-cut segmentation of cursive handwriting in tabular documents

    NASA Astrophysics Data System (ADS)

    Davis, Brian L.; Barrett, William A.; Swingle, Scott D.

    2015-01-01

    Handwritten tabular documents, such as census, birth, death and marriage records, contain a wealth of information vital to genealogical and related research. Much work has been done in segmenting freeform handwriting, however, segmentation of cursive handwriting in tabular documents is still an unsolved problem. Tabular documents present unique segmentation challenges caused by handwriting overlapping cell-boundaries and other words, both horizontally and vertically, as "ascenders" and "descenders" overlap into adjacent cells. This paper presents a method for segmenting handwriting in tabular documents using a min-cut/max-flow algorithm on a graph formed from a distance map and connected components of handwriting. Specifically, we focus on line, word and first letter segmentation. Additionally, we include the angles of strokes of the handwriting as a third dimension to our graph to enable the resulting segments to share pixels of overlapping letters. Word segmentation accuracy is 89.5% evaluating lines of the data set used in the ICDAR2013 Handwriting Segmentation Contest. Accuracy is 92.6% for a specific application of segmenting first and last names from noisy census records. Accuracy for segmenting lines of names from noisy census records is 80.7%. The 3D graph cutting shows promise in segmenting overlapping letters, although highly convoluted or overlapping handwriting remains an ongoing challenge.

  1. Static internal performance of an axisymmetric nozzle with multiaxis thrust-vectoring capability

    NASA Technical Reports Server (NTRS)

    Carson, George T., Jr.; Capone, Francis J.

    1991-01-01

    An investigation was conducted in the static test facility of the Langley 16 Foot Transonic Tunnel in order to determine the internal performance characteristics of a multiaxis thrust vectoring axisymmetric nozzle. Thrust vectoring for this nozzle was achieved by deflection of only the divergent section of this nozzle. The effects of nozzle power setting and divergent flap length were studied at nozzle deflection angles of 0 to 30 at nozzle pressure ratios up to 8.0.

  2. SOLIDS TRANSPORT BETWEEN ADJACENT CAFB FLUIDIZED BEDS

    EPA Science Inventory

    The report gives results of an experimental investigation of a pulsed, dense-phase pneumatic transport system for controlled circulation between adjacent fluidized beds. A model was developed to predict performance. The program provides technical support for EPA's program to demo...

  3. Border separation for adjacent orthogonal fields

    SciTech Connect

    Werner, B.L.; Khan, F.M.; Sharma, S.C.; Lee, C.K.; Kim, T.H. )

    1991-06-01

    Field border separations for adjacent orthogonal fields can be calculated geometrically, given the validity of some important assumptions such as beam alignment and field uniformity. Thermoluminescent dosimetry (TLD) measurements were used to investigate dose uniformity across field junctions as a function of field separation and, in particular, to review the CCSG recommendation for the treatment of medulloblastoma with separate head and spine fields.

  4. Investigation of Nozzle Stability for the First Ovalization Mode by Numerical Solution of the Fluid Structure Interaction Problem

    NASA Astrophysics Data System (ADS)

    Schwane, R.; Zia, Y.

    2005-02-01

    The present paper validates results from numerical simulations for side load generation in rocket nozzles against related data from analytical models that are presently used for rocket engine nozzle design activities. Key words: Nozzle stability; nozzle ovalization; flow structure interaction.

  5. Analytical study of nozzle performance for nuclear thermal rockets

    NASA Technical Reports Server (NTRS)

    Davidian, Kenneth O.; Kacynski, Kenneth J.

    1991-01-01

    Nuclear propulsion has been identified as one of the key technologies needed for human exploration of the Moon and Mars. The Nuclear Thermal Rocket (NTR) uses a nuclear reactor to heat hydrogen to a high temperature followed by expansion through a conventional convergent-divergent nozzle. A parametric study of NTR nozzles was performed using the Rocket Engine Design Expert System (REDES) at the NASA Lewis Research Center. The REDES used the JANNAF standard rigorous methodology to determine nozzle performance over a range of chamber temperatures, chamber pressures, thrust levels, and different nozzle configurations. A design condition was set by fixing the propulsion system exit radius at five meters and throat radius was varied to achieve a target thrust level. An adiabatic wall was assumed for the nozzle, and its length was assumed to be 80 percent of a 15 degree cone. The results conclude that although the performance of the NTR, based on infinite reaction rates, looks promising at low chamber pressures, finite rate chemical reactions will cause the actual performance to be considerably lower. Parameters which have a major influence on the delivered specific impulse value include the chamber temperature and the chamber pressures in the high thrust domain. Other parameters, such as 2-D and boundary layer effects, kinetic rates, and number of nozzles, affect the deliverable performance of an NTR nozzle to a lesser degree. For a single nozzle, maximum performance of 930 seconds and 1030 seconds occur at chamber temperatures of 2700 and 3100 K, respectively.

  6. Effects of nozzle spray angle on droplet size and velocity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spray applicators have many choices in selecting a spray nozzle to make an application of an agricultural product. They must balance flowrate, spray pressure, and nozzle type and setup to deliver their agrochemical in the right droplet size for their particular needs. Studies were conducted to det...

  7. Grit blasting nozzle fabricated from mild tool steel proves satisfactory

    NASA Technical Reports Server (NTRS)

    Mc Farland, J. E.; Turbitt, B.

    1966-01-01

    Dry blasting with glass beads through a nozzle assembly descales both the outside and inside surfaces of tubes of Inconel 718 used for the distribution of gaseous oxygen. The inside of the nozzle is coated with polyurethane and the deflector with a commercially available liquid urethane rubber.

  8. Rayleigh Scattering for Measuring Flow in a Nozzle Testing Facility

    NASA Technical Reports Server (NTRS)

    Gomez, Carlos R.; Panda, Jayanta

    2006-01-01

    A molecular Rayleigh-scattering-based air-density measurement system was built in a large nozzle-and-engine-component test facility for surveying supersonic plumes from jet-engine exhaust. A molecular Rayleigh-scattering-based air-density measurement system was built in a large nozzle-and-enginecomponent test facility for surveying supersonic plumes from jet-engine exhaust

  9. Noise from Aft Deck Exhaust Nozzles: Differences in Experimental Embodiments

    NASA Technical Reports Server (NTRS)

    Bridges, James

    2014-01-01

    Two embodiments of a rectangular nozzle on an aft deck are compared. In one embodiment the lower lip of the nozzle was extended with the sidewalls becoming triangles. In a second embodiment a rectangular nozzle was fitted with a surface that fit flush to the lower lip and extended outward from the sides of the nozzle, approximating a semi-infinite plane. For the purpose of scale-model testing, making the aft deck an integral part of the nozzle is possible for relatively short deck lengths, but a separate plate model is more flexible, accounts for the expanse of deck to the sides of the nozzle, and allows the nozzle to stand off from the deck. Both embodiments were tested and acoustic far-field results were compared. In both embodiments the extended deck introduces a new noise source, but the amplitude of the new source was dependent upon the span (cross-stream dimension) of the aft deck. The noise increased with deck length (streamwise dimension), and in the case of the beveled nozzle it increased with increasing aspect ratio. In previous studies of slot jets in wings it was noted that the increased noise from the extended aft deck appears as a dipole at the aft deck trailing edge, an acoustic source type with different dependence on velocity than jet mixing noise. The extraneous noise produced by the aft deck in the present studies also shows this behavior both in directivity and in velocity scaling.

  10. Combustor nozzle for a fuel-flexible combustion system

    DOEpatents

    Haynes, Joel Meier; Mosbacher, David Matthew; Janssen, Jonathan Sebastian; Iyer, Venkatraman Ananthakrishnan

    2011-03-22

    A combustor nozzle is provided. The combustor nozzle includes a first fuel system configured to introduce a syngas fuel into a combustion chamber to enable lean premixed combustion within the combustion chamber and a second fuel system configured to introduce the syngas fuel, or a hydrocarbon fuel, or diluents, or combinations thereof into the combustion chamber to enable diffusion combustion within the combustion chamber.

  11. The Effect of Nozzle Trailing Edge Thickness on Jet Noise

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda; Kinzie, Kevin; Haskin, Henry

    2004-01-01

    The effect of nozzle trailing edge thickness on broadband acoustic radiation and the production of tones is investigated for coannular nozzles. Experiments were performed for a core nozzle trailing edge thickness between 0.38 mm and 3.17 mm. The on-set of discrete tones was found to be predominantly affected by the velocity ratio, the ratio of the fan velocity to the core velocity, although some dependency on trailing edge thickness was also noted. For a core nozzle trailing edge thickness greater than or equal to 0.89 mm, tones were produced for velocity ratios between 0.91 and 1.61. For a constant nozzle trailing edge thickness, the frequency varied almost linearly with the core velocity. The Strouhal number based on the core velocity changed with nozzle trailing edge thickness and varied between 0.16 and 0.2 for the core nozzles used in the experiments. Increases in broadband noise with increasing trailing edge thickness were observed for tone producing and non-tone producing conditions. A variable thickness trailing edge (crenellated) nozzle resulted in no tonal production and a reduction of the broadband trailing edge noise relative to that of the corresponding constant thickness trailing edge.

  12. Powered fire nozzle for fast penetration of structures: A concept

    NASA Technical Reports Server (NTRS)

    Parker, J. F.; Robbins, R. L.

    1975-01-01

    Nozzle has been proposed with tip that will punch through wall very quickly. It would allow extinguishing agent to be delivered inside closed structure in minimum amount of time. Two versions of nozzle have been conceived: one operated from hydraulic pressure source and one activated by explosive charge.

  13. An overview of spray drift reduction testing of spray nozzles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The importance of the development and testing of drift reduction technologies (DRTs) is increasing. Common spray drift reduction technologies include spray nozzles and spray adjuvants. Following draft procedures developed for a DRT program, three spray nozzles were tested under high air speed cond...

  14. Rapid Fabrication Techniques for Liquid Rocket Channel Wall Nozzles

    NASA Technical Reports Server (NTRS)

    Gradl, Paul R.

    2016-01-01

    The functions of a regeneratively-cooled nozzle are to (1) expand combustion gases to increase exhaust gas velocity while, (2) maintaining adequate wall temperatures to prevent structural failure, and (3) transfer heat from the hot gases to the coolant fluid to promote injector performance and stability. Regeneratively-cooled nozzles are grouped into two categories: tube-wall nozzles and channel wall nozzles. A channel wall nozzle is designed with an internal liner containing a series of integral coolant channels that are closed out with an external jacket. Manifolds are attached at each end of the nozzle to distribute coolant to and away from the channels. A variety of manufacturing techniques have been explored for channel wall nozzles, including state of the art laser-welded closeouts and pressure-assisted braze closeouts. This paper discusses techniques that NASA MSFC is evaluating for rapid fabrication of channel wall nozzles that address liner fabrication, slotting techniques and liner closeout techniques. Techniques being evaluated for liner fabrication include large-scale additive manufacturing of freeform-deposition structures to create the liner blanks. Abrasive water jet milling is being evaluated for cutting the complex coolant channel geometries. Techniques being considered for rapid closeout of the slotted liners include freeform deposition, explosive bonding and Cold Spray. Each of these techniques, development work and results are discussed in further detail in this paper.

  15. Internal Designs Application for Inlet and Nozzle Aeroperformance Improvement

    NASA Technical Reports Server (NTRS)

    Gilinsky, M.; Blankson, I. M.

    2000-01-01

    The following research results are based on development of an approach previously proposed by the authors for optimum nozzle design to obtain maximum thrust. The design was denoted a Telescope nozzle. A Telescope nozzle contains one or several internal designs of certain location, which are inserted at certain locations into a divergent conical or planar main nozzle near its exit. Such a design provides additional thrust augmentation over 20% by comparison with the optimum single nozzle of equivalent lateral area. What is more, recent experimental acoustic tests have discovered an essential noise reduction due to Telescope nozzles application. In this paper, some additional theoretical results are presented for Telescope nozzles and a similar approach is applied for aeroperformance improvement of a supersonic inlet. In addition, a classic gas dynamics problem of a similar supersonic flow into a plate has been analyzed. In some particular cases, new exact analytical solutions are obtained for a flow into a wedge with an oblique shock wave. Numerical simulations were conducted for supersonic flow into a divergent portion of a 2D or axisymmetric nozzle with several plane or conical designs as well as into a 2D or axisymmetric supersonic inlet with a forebody. The 1st order Kryko-Godunov march- ing numerical scheme for inviscid supersonic flows was used. Several cases were tested using the NASA CFL3d code based on full Navier-Stokes equations. Numerical simulation results have confirmed essential benefits of Telescope design applications in propulsion systems.

  16. Internal Designs Application for Inlet and Nozzle Aeroperformance Improvement

    NASA Technical Reports Server (NTRS)

    Gilinsky, M.; Blankson, I. M.

    2000-01-01

    The following research results are based on development of an approach previously proposed by the authors for optimum nozzle design to obtain maximum thrust. The design was denoted a Telescope nozzle. A Telescope nozzle contains one or several internal designs of certain location, which are inserted at certain locations into a divergent conical or planar main nozzle near its exit. Such a design provides additional thrust augmentation over 20% by comparison with the optimum single nozzle of equivalent lateral area. What is more, recent experimental acoustic tests have discovered an essential noise reduction due to Telescope nozzles application. In this paper, some additional theoretical results are presented for Telescope nozzles and a similar approach is applied for aeroperformance improvement of a supersonic inlet. In addition, a classic gas dynamics problem of a similar supersonic flow into a plate has been analyzed. In some particular cases, new exact analytical solutions are obtained for a flow into a wedge with an oblique shock wave. Numerical simulations were conducted for supersonic flow into a divergent portion of a 2D or axisymmetric nozzle with several plane or conuical designs as well as into a 2D or axisymmetric supersonic inlet with a forebody. The 1st order Kryko-Godunov marching numerical scheme for inviscid supersonic flows was used. Several cases were tested using the NASA CFL3d code based on full Navier-Stokes equations. Numerical simulation results have confirmed essential benefits of Telescope design applications in propulsion systems.

  17. Internal Designs Application for Inlet and Nozzle Aeroperformance Improvement

    NASA Technical Reports Server (NTRS)

    Gilinsky, M.; Blankson, I. M.

    2000-01-01

    The following research results are based on development of an approach previously proposed by the authors for optimum nozzle design to obtain maximum thrust. The design was denoted a Telescope nozzle. A Telescope nozzle contains one or several internal designs of certain location, which are inserted at certain locations into a divergent conical or planar main nozzle near its exit. Such a design provides additional thrust augmentation over 20% by comparison with the optimum single nozzle of equivalent lateral area. What is more, recent experimental acoustic tests have discovered an essential noise reduction due to Telescope nozzles application. In this paper, some additional theoretical results are presented for Telescope nozzles and a similar approach is applied for aeroperformance improvement of a supersonic inlet. In addition, a classic gas dynamics problem of a similar supersonic flow into a plate has been analyzed. In some particular cases, new exact analytical solutions are obtained for a flow into a wedge with an oblique shock wave. Numerical simulations were conducted for supersonic flow into a divergent portion of a 2D or axisymmetric nozzle with several plane or conical designs as well as into a 2D or axisymmetric supersonic inlet with a forebody. The 1st order Kryko-Godunov marching numerical scheme for inviscid supersonic flows was used. Several cases were tested using the NASA CFL3d code based on full Navier-Stokes equations. Numerical simulation results have confirmed essential benefits of Telescope design applications in propulsion systems.

  18. Analysis of nitrogen condensation in an expanding nozzle flow

    NASA Technical Reports Server (NTRS)

    Wang, F. C.

    1976-01-01

    Condensation of nitrogen flow in an expanding nozzle flow is analyzed using one-dimensional gas dynamic equations and the equations for nucleation and droplet growth. Effects of variations in the Tolman constant and the mass accommodation factor are discussed as well as the effect of foreign nuclei. Comparisons are made with experimental data obtained from a small, contoured nozzle.

  19. Closeup view looking into the nozzle of the Space Shuttle ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Close-up view looking into the nozzle of the Space Shuttle Main Engine number 2061 looking at the cooling tubes along the nozzle wall and up towards the Main Combustion Chamber and Injector Plate - Space Transportation System, Space Shuttle Main Engine, Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  20. Improved technique for localizing electropolishing features novel nozzles

    NASA Technical Reports Server (NTRS)

    1964-01-01

    Impingement electropolishing is accomplished by use of an electrolyte film, which is evenly distributed by an insulated nozzle designed to match the contour of the workpiece to be treated. The workpiece is connected to the positive terminal of a generator and the nozzle to the negative terminal.

  1. Comparative Results of Tests on Several Different Types of Nozzles

    NASA Technical Reports Server (NTRS)

    Kisenko, M. S.

    1944-01-01

    This paper presents the results of tests conducted to determine the effect of the constructional elements of a Laval nozzle on the velocity and pressure distribution and the magnitude of the reaction force of the jet. The effect was studied of the shapes of the entrance section of the nozzle and three types of divergent sections: namely, straight cone, conoidal with cylindrical and piece and diffuser obtained computationally by a graphical method due to Professor F. I. Frankle. The effect of the divergence angle of the nozzle on the jet reaction was also investigated. The results of the investigation showed that the shape of the generator of the inner surface of the entrance part of the nozzle essentially has no effect on the character of the flow and on the reaction. The nozzle that was obtained by graphical computation assured the possibility of obtaining a flow for which the velocity of all the gas particles is parallel to the axis of symmetry of the nozzle, the reaction being on the average 2 to 3 percent greater than for the usual conical nozzle under the same conditions, For the conical nozzle the maximum reaction was obtained for a cone angle of 25deg to 27deg. At the end of this paper a sample computation is given by the graphical method. The tests were started at the beginning of 1936 and this paper was written at the same time.

  2. Two-Phase Hero Turbine With Curved Nozzles

    NASA Technical Reports Server (NTRS)

    Fabris, Gracio

    1991-01-01

    Proposed hero turbine includes de Laval nozzles modified to new curved, longer, more-gradually-tapered shape that promotes flashing and reduces separation. Turbines designed with new nozzles compete with rotary separator turbines used in geothermal powerplants. Other potential applications include heat pumps and thermal-energy conversion systems.

  3. Investigation of Hypersonic Nozzle Flow Uniformity Using NO Fluorescence

    NASA Technical Reports Server (NTRS)

    O'Byrne, S.; Danehy, P. J.; Houwing, A. F. P.

    2005-01-01

    Planar laser-induced fluorescence visualisation is used to investigate nonuniformities in the flow of a hypersonic conical nozzle. Possible causes for the nonuniformity are outlined and investigated, and the problem is shown to be due to a small step at the nozzle throat. Entrainment of cold boundary layer gas is postulated as the cause of the signal nonuniformity.

  4. Sipunculans and segmentation

    PubMed Central

    Kristof, Alen; Brinkmann, Nora

    2009-01-01

    Comparative molecular, developmental and morphogenetic analyses show that the three major segmented animal groups—Lophotrochozoa, Ecdysozoa and Vertebrata—use a wide range of ontogenetic pathways to establish metameric body organization. Even in the life history of a single specimen, different mechanisms may act on the level of gene expression, cell proliferation, tissue differentiation and organ system formation in individual segments. Accordingly, in some polychaete annelids the first three pairs of segmental peripheral neurons arise synchronously, while the metameric commissures of the ventral nervous system form in anterior-posterior progression. Contrary to traditional belief, loss of segmentation may have occurred more often than commonly assumed, as exemplified in the sipunculans, which show remnants of segmentation in larval stages but are unsegmented as adults. The developmental plasticity and potential evolutionary lability of segmentation nourishes the controversy of a segmented bilaterian ancestor versus multiple independent evolution of segmentation in respective metazoan lineages. PMID:19513266

  5. Segmented trapped vortex cavity

    NASA Technical Reports Server (NTRS)

    Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

    2010-01-01

    An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

  6. [Bilateral segmental neurofibromatosis].

    PubMed

    Rose, I; Vakilzadeh, F

    1991-12-01

    Segmental neurofibromatosis is a rare type of neurofibromatosis. We report a case of bilateral manifestation, review the literature on this extremely uncommon variant, and discuss the possible causative mechanisms and the genetic risk of segmental neurofibromatosis. PMID:1765491

  7. Station Tour: Russian Segment

    NASA Video Gallery

    Expedition 33 Commander Suni Williams concludes her tour of the International Space Station with a visit to the Russian segment, which includes Zarya, the first segment of the station launched in 1...

  8. Effect of several geometric parameters on the static internal performance of three nonaxisymmetric nozzle concepts

    NASA Technical Reports Server (NTRS)

    Berrier, B. L.; Re, R. J.

    1979-01-01

    Effects of several geometric parameters on the internal performance of nonaxisymmetric convergent-divergent, single-ramp expansion, and wedge nozzles were investigated at nozzle pressure ratios up to approximately 10. In addition, two different thrust-vectoring schemes were investigated with the wedge nozzle. The results indicated that as with conventional round nozzles, peak nonaxisymmetric nozzle, internal performance occurred near the nozzle pressure ratio required for fully expanded exhaust flow. Nozzle sidewall length or area generally had little effect on the internal performance of the nozzles investigated.

  9. Thermographic Leak Detection of the Space Shuttle Main Engine Nozzle

    NASA Technical Reports Server (NTRS)

    Walker, James L.; Russell, Samuel S.

    1999-01-01

    The Space Shuttle Main Engines Nozzles consist of over one thousand tapered Inconel coolant tubes brazed to a stainless steel structural jacket. Liquid Hydrogen flows through the tubing, from the aft to forward end of the nozzle, under high pressure to maintain a thermal balance between the rocket exhaust and the nozzle wall. Three potential problems occur within the SSME nozzle coolant tubes as a result of manufacturing anomalies and the highly volatile service environment including poor or incomplete bonding of the tubes to the structural jacket, cold wall leaks and hot wall leaks. Of these conditions the identification of cold wall leaks has been the most problematic. The methods and results presented in this summary addresses the thermographic identification of cold wall "interstitial" leaks between the structural jacket and coolant tubes of the Space Shuttle Main Engines Nozzles.

  10. Shape memory alloy actuated adaptive exhaust nozzle for jet engine

    NASA Technical Reports Server (NTRS)

    Song, Gangbing (Inventor); Ma, Ning (Inventor)

    2009-01-01

    The proposed adaptive exhaust nozzle features an innovative use of the shape memory alloy (SMA) actuators for actively control of the opening area of the exhaust nozzle for jet engines. The SMA actuators remotely control the opening area of the exhaust nozzle through a set of mechanism. An important advantage of using SMA actuators is the reduction of weight of the actuator system for variable area exhaust nozzle. Another advantage is that the SMA actuator can be activated using the heat from the exhaust and eliminate the need of other energy source. A prototype has been designed and fabricated. The functionality of the proposed SMA actuated adaptive exhaust nozzle is verified in the open-loop tests.

  11. Experimental determination of three dimensional liquid rocket nozzle admittances.

    NASA Technical Reports Server (NTRS)

    Zinn, B. T.; Bell, W. A.; Daniel, B. R.; Smith, A. J., Jr.

    1972-01-01

    The three dimensional nozzle admittance, an important parameter in combustion instability studies, was experimentally measured for several nozzle configurations. The admittance values were obtained using a modification of the classical impedance tube technique. The modified impedance tube method measures the admittance of a duct termination in the presence of one dimensional mean flow and three dimensional oscillations. Values of the nozzle admittance were obtained from pressure amplitude measurements taken at discrete points along the length of the tube. To determine the effects of nozzle geometry, nozzles were tested with half-angles of 15, 30, and 45 degrees and entrance Mach numbers of 0.08, 0.16, and 0.20. The admittance results are presented as functions of nondimensional frequency for mixed first tangential-longitudinal modes. These results are compared with available theoretical predictions and favorable agreement between theory and experiment is shown.

  12. Transonic wind tunnel test of a supersonic nozzle installation

    NASA Technical Reports Server (NTRS)

    Yetter, J. A.; Evelyn, G. B.; Mercer, C.

    1982-01-01

    The design of the propulsion system installation affects strongly the total drag and overall performance of an aircraft, and the concept, placement, and integration details of the exhaust nozzle are major considerations in the configuration definition. As part of the NASA Supersonic Cruise Research (SCR) program, a wind tunnel test program has been conducted to investigate exhaust nozzle-airframe interactions at transonic speeds. First phase testing is to establish guidelines for follow-on testing. A summary is provided of the results of first phase testing, taking into account the test approach, the effect of nozzle closure on aircraft aerodynamic characteristics, nozzle installation effects and nacelle interference drag, and an analytical study of the effects of nozzle closure on the aircraft.

  13. Possible and Impossible Segments.

    ERIC Educational Resources Information Center

    Walker, Rachel; Pullum, Geoffrey K.

    1999-01-01

    Examines the relationship between phonetic possibility and phonological permissibility of segment types. Specific focus is on whether there are any phonetically impossible segments phonologically permissible, and whether there are any phonetically possible segments phonologically impermissable. Examines the case of nasality spreading in Sudanese…

  14. Novel design for transparent high-pressure fuel injector nozzles.

    PubMed

    Falgout, Z; Linne, M

    2016-08-01

    The efficiency and emissions of internal combustion (IC) engines are closely tied to the formation of the combustible air-fuel mixture. Direct-injection engines have become more common due to their increased practical flexibility and efficiency, and sprays dominate mixture formation in these engines. Spray formation, or rather the transition from a cylindrical liquid jet to a field of isolated droplets, is not completely understood. However, it is known that nozzle orifice flow and cavitation have an important effect on the formation of fuel injector sprays, even if the exact details of this effect remain unknown. A number of studies in recent years have used injectors with optically transparent nozzles (OTN) to allow observation of the nozzle orifice flow. Our goal in this work is to design various OTN concepts that mimic the flow inside commercial injector nozzles, at realistic fuel pressures, and yet still allow access to the very near nozzle region of the spray so that interior flow structure can be correlated with primary breakup dynamics. This goal has not been achieved until now because interior structures can be very complex, and the most appropriate optical materials are brittle and easily fractured by realistic fuel pressures. An OTN design that achieves realistic injection pressures and grants visual access to the interior flow and spray formation will be explained in detail. The design uses an acrylic nozzle, which is ideal for imaging the interior flow. This nozzle is supported from the outside with sapphire clamps, which reduces tensile stresses in the nozzle and increases the nozzle's injection pressure capacity. An ensemble of nozzles were mechanically tested to prove this design concept. PMID:27587161

  15. Analysis, design and testing of high pressure waterjet nozzles

    NASA Technical Reports Server (NTRS)

    Mazzoleni, Andre P.

    1996-01-01

    The Hydroblast Research Cell at MSFC is both a research and a processing facility. The cell is used to investigate fundamental phenomena associated with waterjets as well as to clean hardware for various NASA and contractor projects. In the area of research, investigations are made regarding the use of high pressure waterjets to strip paint, grease, adhesive and thermal spray coatings from various substrates. Current industrial methods of cleaning often use ozone depleting chemicals (ODC) such as chlorinated solvents, and high pressure waterjet cleaning has proven to be a viable alternative. Standard methods of waterjet cleaning use hand held or robotically controlled nozzles. The nozzles used can be single-stream or multijet nozzles, and the multijet nozzles may be mounted in a rotating head or arranged in a fan-type shape. We consider in this paper the use of a rotating, multijet, high pressure water nozzle which is robotically controlled. This method enables rapid cleaning of a large area, but problems such as incomplete coverage (e.g. the formation of 'islands' of material not cleaned) and damage to the substrate from the waterjet have been observed. In addition, current stripping operations require the nozzle to be placed at a standoff distance of approximately 2 inches in order to achieve adequate performance. This close proximity of the nozzle to the target to be cleaned poses risks to the nozzle and the target in the event of robot error or the striking of unanticipated extrusions on the target surface as the nozzle sweeps past. Two key motivations of this research are to eliminate the formation of 'coating islands' and to increase the allowable standoff distance of the nozzle.

  16. Novel design for transparent high-pressure fuel injector nozzles

    NASA Astrophysics Data System (ADS)

    Falgout, Z.; Linne, M.

    2016-08-01

    The efficiency and emissions of internal combustion (IC) engines are closely tied to the formation of the combustible air-fuel mixture. Direct-injection engines have become more common due to their increased practical flexibility and efficiency, and sprays dominate mixture formation in these engines. Spray formation, or rather the transition from a cylindrical liquid jet to a field of isolated droplets, is not completely understood. However, it is known that nozzle orifice flow and cavitation have an important effect on the formation of fuel injector sprays, even if the exact details of this effect remain unknown. A number of studies in recent years have used injectors with optically transparent nozzles (OTN) to allow observation of the nozzle orifice flow. Our goal in this work is to design various OTN concepts that mimic the flow inside commercial injector nozzles, at realistic fuel pressures, and yet still allow access to the very near nozzle region of the spray so that interior flow structure can be correlated with primary breakup dynamics. This goal has not been achieved until now because interior structures can be very complex, and the most appropriate optical materials are brittle and easily fractured by realistic fuel pressures. An OTN design that achieves realistic injection pressures and grants visual access to the interior flow and spray formation will be explained in detail. The design uses an acrylic nozzle, which is ideal for imaging the interior flow. This nozzle is supported from the outside with sapphire clamps, which reduces tensile stresses in the nozzle and increases the nozzle's injection pressure capacity. An ensemble of nozzles were mechanically tested to prove this design concept.

  17. Multi-segment detector

    NASA Technical Reports Server (NTRS)

    George, Peter K. (Inventor)

    1978-01-01

    A plurality of stretcher detector segments are connected in series whereby detector signals generated when a bubble passes thereby are added together. Each of the stretcher detector segments is disposed an identical propagation distance away from passive replicators wherein bubbles are replicated from a propagation path and applied, simultaneously, to the stretcher detector segments. The stretcher detector segments are arranged to include both dummy and active portions thereof which are arranged to permit the geometry of both the dummy and active portions of the segment to be substantially matched.

  18. Combustor exhaust-emissions and blowout-limits with diesel number 2 and jet A fuels utilizing air-atomizing and pressure atomizing nozzles

    NASA Technical Reports Server (NTRS)

    Ingebo, R. D.; Norgren, C. T.

    1975-01-01

    Experimental tests with diesel number 2 and Jet A fuels were conducted in a combustor segment to obtain comparative data on exhaust emissions and blowout limits. An air-atomizing nozzle was used to inject the fuels. Tests were also made with diesel number 2 fuel using a pressure-atomizing nozzle to determine the effectiveness of the air-atomizing nozzle in reducing exhaust emissions. Test conditions included fuel-air ratios of 0.008 to 0.018, inlet-air total pressures and temperatures of 41 to 203 newtons per square centimeter and 477 to 811 K, respectively, and a reference velocity of 21.3 meters per second. Smoke number and unburned hydrocarbons were twice as high with diesel number 2 as with Jet A fuel. This was attributed to diesel number 2 having a higher concentration of aromatics and lower volatility than Jet A fuel. Oxides of nitrogen, carbon monoxide, and blowout limits were approximately the same for the two fuels. The air-atomizing nozzle, as compared with the pressure-atomizing nozzle, reduced oxides-of-nitrogen by 20 percent, smoke number by 30 percent, carbon monoxide by 70 percent, and unburned hydrocarbons by 50 percent when used with diesel number 2 fuel.

  19. Convoluted nozzle design for the RL10 derivative 2B engine

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The convoluted nozzle is a conventional refractory metal nozzle extension that is formed with a portion of the nozzle convoluted to show the extendible nozzle within the length of the rocket engine. The convoluted nozzle (CN) was deployed by a system of four gas driven actuators. For spacecraft applications the optimum CN may be self-deployed by internal pressure retained, during deployment, by a jettisonable exit closure. The convoluted nozzle is included in a study of extendible nozzles for the RL10 Engine Derivative 2B for use in an early orbit transfer vehicle (OTV). Four extendible nozzle configurations for the RL10-2B engine were evaluated. Three configurations of the two position nozzle were studied including a hydrogen dump cooled metal nozzle and radiation cooled nozzles of refractory metal and carbon/carbon composite construction respectively.

  20. Color image segmentation

    NASA Astrophysics Data System (ADS)

    McCrae, Kimberley A.; Ruck, Dennis W.; Rogers, Steven K.; Oxley, Mark E.

    1994-03-01

    The most difficult stage of automated target recognition is segmentation. Current segmentation problems include faces and tactical targets; previous efforts to segment these objects have used intensity and motion cues. This paper develops a color preprocessing scheme to be used with the other segmentation techniques. A neural network is trained to identify the color of a desired object, eliminating all but that color from the scene. Gabor correlations and 2D wavelet transformations will be performed on stationary images; and 3D wavelet transforms on multispectral data will incorporate color and motion detection into the machine visual system. The paper will demonstrate that color and motion cues can enhance a computer segmentation system. Results from segmenting faces both from the AFIT data base and from video taped television are presented; results from tactical targets such as tanks and airplanes are also given. Color preprocessing is shown to greatly improve the segmentation in most cases.

  1. Feedback mechanism for smart nozzles and nebulizers

    DOEpatents

    Montaser, Akbar [Potomac, MD; Jorabchi, Kaveh [Arlington, VA; Kahen, Kaveh [Kleinburg, CA

    2009-01-27

    Nozzles and nebulizers able to produce aerosol with optimum and reproducible quality based on feedback information obtained using laser imaging techniques. Two laser-based imaging techniques based on particle image velocimetry (PTV) and optical patternation map and contrast size and velocity distributions for indirect and direct pneumatic nebulizations in plasma spectrometry. Two pulses from thin laser sheet with known time difference illuminate droplets flow field. Charge coupled device (CCL)) captures scattering of laser light from droplets, providing two instantaneous particle images. Pointwise cross-correlation of corresponding images yields two-dimensional velocity map of aerosol velocity field. For droplet size distribution studies, solution is doped with fluorescent dye and both laser induced florescence (LIF) and Mie scattering images are captured simultaneously by two CCDs with the same field of view. Ratio of LIF/Mie images provides relative droplet size information, then scaled by point calibration method via phase Doppler particle analyzer.

  2. Plumb nozzle for nuclear fuel assembly

    SciTech Connect

    Silverblatt, B.L.

    1986-02-25

    An elongated nuclear reactor fuel assembly is described having an asymmetric weight distribution across a cross section, including a nozzle affixed to one end of the fuel assembly having lifting surfaces formed thereon on which the fuel assembly can be supported when suspended from the surfaces. At least one of the lifting surfaces is located at a first elevation relative to the longitudinal axis of the fuel assembly. A second of the lifting surfaces is located at a second elevation different from the first elevation wherein the difference in the first and second elevations is sized to offset the asymmetric weight distribution when the fuel assembly is supported from the first and second surface so that when so supported the fuel assembly will hang plumb.

  3. Multidisciplinary Approach to Linear Aerospike Nozzle Optimization

    NASA Technical Reports Server (NTRS)

    Korte, J. J.; Salas, A. O.; Dunn, H. J.; Alexandrov, N. M.; Follett, W. W.; Orient, G. E.; Hadid, A. H.

    1997-01-01

    A model of a linear aerospike rocket nozzle that consists of coupled aerodynamic and structural analyses has been developed. A nonlinear computational fluid dynamics code is used to calculate the aerodynamic thrust, and a three-dimensional fink-element model is used to determine the structural response and weight. The model will be used to demonstrate multidisciplinary design optimization (MDO) capabilities for relevant engine concepts, assess performance of various MDO approaches, and provide a guide for future application development. In this study, the MDO problem is formulated using the multidisciplinary feasible (MDF) strategy. The results for the MDF formulation are presented with comparisons against sequential aerodynamic and structural optimized designs. Significant improvements are demonstrated by using a multidisciplinary approach in comparison with the single- discipline design strategy.

  4. Noise Prediction Module for Offset Stream Nozzles

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda S.

    2011-01-01

    A Modern Design of Experiments (MDOE) analysis of data acquired for an offset stream technology was presented. The data acquisition and concept development were funded under a Supersonics NRA NNX07AC62A awarded to Dimitri Papamoschou at University of California, Irvine. The technology involved the introduction of airfoils in the fan stream of a bypass ratio (BPR) two nozzle system operated at transonic exhaust speeds. The vanes deflected the fan stream relative to the core stream and resulted in reduced sideline noise for polar angles in the peak jet noise direction. Noise prediction models were developed for a range of vane configurations. The models interface with an existing ANOPP module and can be used or future system level studies.

  5. Multidisciplinary Approach to Aerospike Nozzle Design

    NASA Technical Reports Server (NTRS)

    Korte, J. J.; Salas, A. O.; Dunn, H. J.; Alexandrov, N. M.; Follett, W. W.; Orient, G. E.; Hadid, A. H.

    1997-01-01

    A model of a linear aerospike rocket nozzle that consists of coupled aerodynamic and structural analyses has been developed. A nonlinear computational fluid dynamics code is used to calculate the aerodynamic thrust, and a three-dimensional finite-element model is used to determine the structural response and weight. The model will be used to demonstrate multidisciplinary design optimization (MDO) capabilities for relevant engine concepts, assess performance of various MDO approaches, and provide a guide for future application development. In this study, the MDO problem is formulated using the multidisciplinary feasible (MDF) strategy. The results for the MDF formulation are presented with comparisons against separate aerodynamic and structural optimized designs. Significant improvements are demonstrated by using a multidisciplinary approach in comparison with the single-discipline design strategy.

  6. Improved ablative materials for the ASRM nozzle

    NASA Technical Reports Server (NTRS)

    Canfield, A.; Clinton, R. G.; Armour, W.; Koenig, J.

    1992-01-01

    Rayon precursor carbon-cloth phenolic was developed more than 30 years ago and is used in most nozzles today including the Poseidon, Trident, Peacekeeper, Small ICBM, Space Shuttle, and numerous tactical and space systems. Specifications and manufacturing controls were placed on these materials and, once qualified, a no-change policy was instituted. The current material is acceptable; however, prepreg variability does not always accommodate the requirements of automation. The advanced solid rocket motor requires material with less variability for automated manufacturing. An advanced solid rocket motor materials team, composed of NASA, Thiokol, Aerojet, SRI, and Lockheed specialists, along with materials suppliers ICI Fiberite/Polycarbon, BP Chemicals/Hitco, and Amoco, embarked on a program to improve the current materials. The program consisted of heat treatment studies and standard and low-density material improvements evaluation. Improvements evaluated included fiber/fabric heat treatments, weave variations, resin application methods, process controls, and monitors.

  7. Serrating Nozzle Surfaces for Complete Transfer of Droplets

    NASA Technical Reports Server (NTRS)

    Kim, Chang-Jin " CJ" ; Yi, Uichong

    2010-01-01

    A method of ensuring the complete transfer of liquid droplets from nozzles in microfluidic devices to nearby surfaces involves relatively simple geometric modification of the nozzle surfaces. The method is especially applicable to nozzles in print heads and similar devices required to dispense liquid droplets having precise volumes. Examples of such devices include heads for soft printing of ink on paper and heads for depositing droplets of deoxyribonucleic acid (DNA) or protein solutions on glass plates to form microarrays of spots for analysis. The main purpose served by the present method is to ensure that droplets transferred from a nozzle have consistent volume, as needed to ensure accuracy in microarray analysis or consistent appearance of printed text and images. In soft printing, droplets having consistent volume are generated inside a print head, but in the absence of the present method, the consistency is lost in printing because after each printing action (in which a drop is ejected from a nozzle), a small residual volume of liquid remains attached to the nozzle. By providing for complete transfer of droplets (and thus eliminating residual liquid attached to the nozzle) the method ensures consistency of volume of transferred droplets. An additional benefit of elimination of residue is prevention of cross-contamination among different liquids printed through the same nozzle a major consideration in DNA microarray analysis. The method also accelerates the printing process by minimizing the need to clean a printing head to prevent cross-contamination. Soft printing involves a hydrophobic nozzle surface and a hydrophilic print surface. When the two surfaces are brought into proximity such that a droplet in the nozzle makes contact with the print surface, a substantial portion of the droplet becomes transferred to the print surface. Then as the nozzle and the print surface are pulled apart, the droplet is pulled apart and most of the droplet remains on the

  8. The Low Frequency Aeroacoustics of Buried Nozzle Systems

    NASA Astrophysics Data System (ADS)

    Taylor, M. V.; Crighton, D. G.; Cargill, A. M.

    1993-05-01

    A simplified model of a "buried nozzle" aeroengine system is considered. The primary flow issues into a co-annular flow within a mixing chamber, and then the co-annular flow issues into the ambient medium from a secondary nozzle. Within the mixing chamber only fine scale mixing takes place, and shear layers within the mixing chamber and downstream of the secondary nozzle are assumed to sustain large scale instability waves. Excitation of this system is provided by low frequency plane waves, incident from upstream on the primary nozzle (and emanating from combustion processes in the hot core of an aeroengine). The response of this system, in the acoustic far field and in the mixing chamber, is obtained analytically from the asymptotic solution, at low frequency, of model sub-problems the solutions of which determine the wave reflection and transmission processes at the primary and secondary nozzles. In these sub-problems the shear layers are represented by vortex sheets and the nozzle walls by semi-infinite circular ducts, with Kutta conditions imposed on the unsteady flow at the primary and secondary nozzle lips. Analytical descriptions are given of the various wave modes (quasi-plane acoustic waves, and instability waves localized on the primary and secondary shear layers), of the acoustic field strength and directivity (essentially monopole, dipole and quadrupole fields), and of the conditions under which near-resonant response may occur, with large amplitudes of the perturbations in the mixing chamber and in the acoustic field.

  9. Research on stability of nozzle-floating plate institution

    NASA Astrophysics Data System (ADS)

    Huang, Bin; Tao, Jiayue; Yi, Jiajing; Chen, Shijing

    2016-01-01

    In this paper, air hammer instability of nozzle-floating plate institution in gas lubricated force sensor were studied. Through establishment of the theoretical model for the analysis of the nozzle-floating plate institution stability, combined with air hammer stability judgment theorems, we had some simulation research on the radius of the nozzle, the radius of the pressure chamber, pressure chamber depth, orifice radius and the relationship between air supply pressure and bearing capacity, in order to explore the instability mechanism of nozzle-floating plate institution. For conducting experimental observations for the stability of two groups nozzle-floating plate institution, which have typical structural parameters conducted experimental observations. We set up a special experimental device, verify the correctness of the theoretical study and simulation results. This paper shows that in the nozzle-floating plate institution, increasing the nozzle diameter, reduced pressure chamber radius, reducing the depth of the pressure chamber and increase the supply orifice radius, and other measures is conducive to system stability. Results of this study have important implications for research and design of gas lubricated force sensor.

  10. Influence of nozzle random side loads on launch vehicle dynamics

    NASA Astrophysics Data System (ADS)

    Srivastava, Nilabh; Tkacik, Peter T.; Keanini, Russell G.

    2010-08-01

    It is well known that the dynamic performance of a rocket or launch vehicle is enhanced when the length of the divergent section of its nozzle is reduced or the nozzle exit area ratio is increased. However, there exists a significant performance trade-off in such rocket nozzle designs due to the presence of random side loads under overexpanded nozzle operating conditions. Flow separation and the associated side-load phenomena have been extensively investigated over the past five decades; however, not much has been reported on the effect of side loads on the attitude dynamics of rocket or launch vehicle. This paper presents a quantitative investigation on the influence of in-nozzle random side loads on the attitude dynamics of a launch vehicle. The attitude dynamics of launch vehicle motion is captured using variable-mass control-volume formulation on a cylindrical rigid sounding rocket model. A novel physics-based stochastic model of nozzle side-load force is developed and embedded in the rigid-body model of rocket. The mathematical model, computational scheme, and results corresponding to side loading scenario are subsequently discussed. The results highlight the influence of in-nozzle random side loads on the roll, pitch, yaw, and translational dynamics of a rigid-body rocket model.

  11. Calculation of propulsive nozzle flowfields in multidiffusing chemically reacting environments

    NASA Astrophysics Data System (ADS)

    Kacynski, Kenneth John

    1994-04-01

    An advanced engineering model has been developed to aid in the analysis and design of hydrogen/oxygen chemical rocket engines. The complete multispecies, chemically reacting and multidiffusing Navier-Stokes equations are modelled, including the Soret thermal diffusion and the Dufour energy transfer terms. In addition to the spectrum of multispecies aspects developed, the model developed in this study is also conservative in axisymmetric flow for both inviscid and viscous flow environments and the boundary conditions employ a viscous, chemically reacting, reference plane characteristics method. Demonstration cases are presented for a 1030:1 area ratio nozzle, a 25 lbf film cooled nozzle, and a transpiration cooled plug and spool rocket engine. The results indicate that the thrust coefficient predictions of the 1030:1 and the 25 lbf film cooled nozzle are within 0.2 to 0.5 percent, respectively, of experimental measurements when all of the chemical reaction and diffusion terms are considered. Further, the model's predictions agree very well with the heat transfer measurements made in all of the nozzle test cases. The Soret thermal diffusion term is demonstrated to have a significant effect on the predicted mass fraction of hydrogen along the wall of the nozzle in both the laminar flow 1030:1 nozzle and the turbulent flow plug and spool nozzle analysis cases performed. Further, the Soret term was shown to represent an important fraction of the diffusion fluxes occurring in a transpiration cooled rocket engine.

  12. An experimental study on jets issuing from elliptic inclined nozzles

    NASA Astrophysics Data System (ADS)

    New, T. H.

    2009-06-01

    This paper reports on an experimental flow visualisation and digital particle image velocimetry investigation on forced jets exhausting from aspect ratio equal to three elliptic nozzles with exits inclined at 30° and 60°. Flow images show that shear layer instabilities and subsequent vortex roll-ups are formed parallel to the inclined nozzle exits at 30° incline and that rapid re-orientation of the vortex roll-ups occurs at 60° incline. Flow observations also show that strong axis-switching occurs in a non-inclined elliptic nozzle. However, 30° and 60° elliptic inclined nozzles produce significant distortions to and suppression of the axis-switching behaviour, respectively. As a result, flow stresses and turbulent kinetic energy distributions become increasingly asymmetric. Their coherency and magnitudes along the shorter nozzle lengths also vary significantly. This can be attributed to the dissimilar formations of vortex roll-ups and rib structures, as well as unequal mutual interactions between them as the incline-angle increases. Lastly, results also show that unlike circular inclined nozzles, elliptic inclined nozzles do not produce serpentine-shaped jet columns nor lead to significant lateral jet-spread at large incline-angles.

  13. Unsteady transitions of separation patterns in single expansion ramp nozzle

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Xu, J.; Yu, K.; Mo, J.

    2015-11-01

    The single expansion ramp nozzle is one of the optimal configurations for a planar rocket-based combined cycle engine because of its good integration and self-adaptability at off-design operation. The single expansion ramp nozzle is seriously overexpanded when the vehicle is at low speed, resulting in complex flow separation phenomena. Several separation patterns have been found in the single expansion ramp nozzle. Numerical simulations have shown that the transition between these separation patterns occurs in the nozzle startup and shutdown processes. However, only a few relevant experimental studies have been reported. This study reproduces the nozzle startup and shutdown processes using wind tunnel experiments. Two restricted shock separation patterns are observed in the experiment, namely, a separation bubble either forms on the ramp or the flap. The detailed flow fields in the transition processes are captured using a high-speed camera. The shock wave structures in the two separation patterns, influences of the nozzle pressure ratio (NPR) on the separation patterns and changes of the shock waves in the transition processes are discussed in detail. Shock wave instabilities accompany the separation transition, which usually takes less than 5 ms. The nozzle pressure ratios corresponding to the separation pattern transition are different in the startup and shutdown processes, which leads to a hysteresis effect.

  14. A shear reversal nozzle for efficient gas atomization

    SciTech Connect

    Brown, S.W.

    1992-12-01

    The primary purpose of this report is to establish definitive rationale and technical drivers for atomizing nozzles that employ the shear reversal principle. In a shear reversing nozzle, the liquid to be atomized is introduced into a supersonic gas flow and is allowed to accelerate to a velocity near that of the gas before it exits the nozzle. The pressure conditions at the exit of the nozzle are managed in such a manner to produce a strong normal shock wave in the gas flow field. The shock wave causes a large reduction in the gas velocity at the exit of the nozzle. Because the liquid is traveling near the initial gas velocity as it exits the nozzle, it now encounters a relatively slow moving gas flow field, which causes further reductions in the particle size. An elementary atomizing model is presented comprising two distinct processes: (1) particle divisions and (2) particle shearing. From the model, the primary process variables were identified and strategies were presented to maximize the production of fine diameter particles. In addition, an elementary finite difference model was presented to aid in the determination of the overall length of the shear reversing nozzle. Finally, a procedure was given to establish proper sizing of the components involved.

  15. Droplet formation under the effect of a flexible nozzle plate.

    PubMed

    Sangplung, S; Liburdy, J A

    2009-09-01

    Droplet formation from a flexible nozzle plate driven by a prescribed-waveform excitation of a piezoelectric is numerically investigated using a computational fluid dynamics (CFD) model with the volume of fluid (VOF) method. The droplet generator with a flexible nozzle plate, which is free to vibrate due to the pressure acting on the plate, is modeled in a CFD computational domain. The CFD analysis includes the fluid-structure interaction between fluid and a flexible plate using large deflection theory. The problem is characterized by the nondimensional variables based on the capillary parameters of time, velocity, and pressure. The CFD model is validated with the experiment results. This study examines the characteristics of the applied waveforms and nozzle plate material properties to change the vibrational characteristics of the nozzle plate. The effect of fluid properties on the droplet formation process is also investigated focusing on surface tension and viscous forces. Increasing the impulse of the piezoelectric can be used to cause a higher droplet velocity and it is shown that the vibration of the nozzle plate has a strong effect on the droplet velocity, shape, and volume. Surface tension has a strong influence on the droplet formation characteristics in contrast to viscous forces. For the combination of a fluid with high surface tension and the most flexible nozzle plate, this system cannot cause the droplet ejected out of the nozzle. PMID:19501837

  16. Static investigation of several yaw vectoring concepts on nonaxisymmetric nozzles

    NASA Technical Reports Server (NTRS)

    Mason, M. L.; Berrier, B. L.

    1985-01-01

    A test has been conducted in the static test facility of the Langley 16-Foot Transonic Tunnel to determine the flow-turning capability and the effects on nozzle internal performance of several yaw vectoring concepts. Nonaxisymmetric convergent-divergent nozzles with throat areas simulating dry and afterburning power settings and single expansion ramp nozzles with a throat area simulating a dry power setting were modified for yaw thrust vectoring. Forward-thrust and pitch-vectored nozzle configurations were tested with each yaw vectoring concept. Four basic yaw vectoring concepts were investigated on the nonaxisymmetric convergent-divergent nozzles: (1) translating sidewall; (2) downstream (of throat) flaps; (3) upstream (of throat) port/flap; and (4) powered rudder. Selected combinations of the rudder with downstream flaps or upstream port/flap were also tested. A single yaw vectoring concept, post-exit flaps, was investigated on the single expansion ramp nozzles. All testing was conducted at static (no external flow) conditions and nozzle pressure ratios varied from 2.0 up to 10.0.

  17. Probability of rupture of multiple fault segments

    USGS Publications Warehouse

    Andrews, D.J.; Schwerer, E.

    2000-01-01

    Fault segments identified from geologic and historic evidence have sometimes been adopted as features limiting the likely extends of earthquake ruptures. There is no doubt that individual segments can sometimes join together to produce larger earthquakes. This work is a trial of an objective method to determine the probability of multisegment ruptures. The frequency of occurrence of events on all conjectured combinations of adjacent segments in northern California is found by fitting to both geologic slip rates and to an assumed distribution of event sizes for the region as a whole. Uncertainty in the shape of the distribution near the maximum magnitude has a large effect on the solution. Frequencies of individual events cannot be determined, but it is possible to find a set of frequencies to fit a model closely. A robust conclusion for the San Francisco Bay region is that large multisegment events occur on the San Andreas and San Gregorio faults, but single-segment events predominate on the extended Hayward and Calaveras strands of segments.

  18. Final data report: Plenum-Nozzle Flow Characteristics Experiment

    SciTech Connect

    Duignan, M.R.; May, C.P.

    1993-09-01

    A database was developed for the flow of water through a scaled nozzle of a Savannah River Site (SRS) reactor inlet plenum. The water flow in the nozzle was such that it ranged from stratified to water-solid conditions. Data on the entry of air into the nozzle and plenum as a function of water flow are of interest in loss-of-coolant studies. The scaled nozzle was 0.44 m long, had an entrance diameter of 0.095 m, an exit opening of 0.058 m {times} 0.356 m, and an exit hydraulic diameter approximately equal to that of the inlet. Within the nozzle were three flow-straightening vanes which divided the flow path into four channels. This report includes all of the data taken for the first phase of the Plenum-Nozzle and Cold-Leg Vertical Process-Pipe Flow Characteristics Experiments: Plenum-Nozzle Experiment. Those data include daily reference checks, to determine proper operation of all instrumentation before the experiment was run, and the actual data themselves in engineering units. Not included are the videographic data which are available for each test run. However, there are four (4) 3/4 in. -video tapes of visual data and the specific tape and the location on that tape are indicated for each test run on the data sheets. The database is from sixteen test modes (e.g., flow direction, location of pipe break, air-water or just water, single nozzle or three nozzle). The flow rates ranged to approximately 320 gpm ({approx}10 kgpm prototypic) for both air and water. All data were taken at steady-state, isothermal (300 K{plus_minus}1.5 K), and atmospheric pressure conditions.

  19. Application of LBB to a nozzle-pipe interface

    SciTech Connect

    Yu, Y.J.; Sohn, G.H.; Kim, Y.J.

    1997-04-01

    Typical LBB (Leak-Before-Break) analysis is performed for the highest stress location for each different type of material in the high energy pipe line. In most cases, the highest stress occurs at the nozzle and pipe interface location at the terminal end. The standard finite element analysis approach to calculate J-Integral values at the crack tip utilizes symmetry conditions when modeling near the nozzle as well as away from the nozzle region to minimize the model size and simplify the calculation of J-integral values at the crack tip. A factor of two is typically applied to the J-integral value to account for symmetric conditions. This simplified analysis can lead to conservative results especially for small diameter pipes where the asymmetry of the nozzle-pipe interface is ignored. The stiffness of the residual piping system and non-symmetries of geometry along with different material for the nozzle, safe end and pipe are usually omitted in current LBB methodology. In this paper, the effects of non-symmetries due to geometry and material at the pipe-nozzle interface are presented. Various LBB analyses are performed for a small diameter piping system to evaluate the effect a nozzle has on the J-integral calculation, crack opening area and crack stability. In addition, material differences between the nozzle and pipe are evaluated. Comparison is made between a pipe model and a nozzle-pipe interface model, and a LBB PED (Piping Evaluation Diagram) curve is developed to summarize the results for use by piping designers.

  20. Fuel Injector Nozzle For An Internal Combustion Engine

    DOEpatents

    Cavanagh, Mark S.; Urven, Jr.; Roger L.; Lawrence, Keith E.

    2006-04-25

    A direct injection fuel injector includes a nozzle tip having a plurality of passages allowing fluid communication between an inner nozzle tip surface portion and an outer nozzle tip surface portion and directly into a combustion chamber of an internal combustion engine. A first group of the passages have inner surface apertures located substantially in a first common plane. A second group of the passages have inner surface apertures located substantially in at least a second common plane substantially parallel to the first common plane. The second group has more passages than the first group.