Science.gov

Sample records for calculating pipe failure

  1. Review of Failure Probability Calculations for HFIR Primary Coolant System Piping

    SciTech Connect

    Simonen, Fredric A.

    2001-10-31

    During July 2001, Pacific Northwest National Laboratory was requested by the U.S. Department of Energy, Office of Nuclear Facilities Management, Office of Nuclear Energy, Science and Technology, Germantown, Maryland, to review calculations of piping failure probabilities for the High Flux Test Reactor (HFIR) located at and operated by the Oak Ridge National Laboratory (ORNL). The objective of the failure probability calculations was to estimate the probabilities of large leaks (>1500 gpm) that are of sufficient size to disable the primary coolant system of HFIR to the extent that there is a potential for core damage. PNNL reviewed the computational methods and the inputs to the calculations along with an evaluation of potential failure mechanisms not explicitly addressed by the ORNL calculations. The review concluded that the calculated failure probabilities even with consideration of uncertainties in the calculations and of other potential failure mechanisms provide a high level of confidence that failure frequencies are less than the stated goal of 10-6 piping failures per year.

  2. Lower San Fernando corrugated metal pipe failure

    SciTech Connect

    Bardet, J.P.; Davis, C.A.

    1995-12-31

    During the January 17, 1994, Northridge earthquake, a 2.4 m diameter corrugated metal pipe was subjected to 90 m of extensive lateral crushing failure at the Lower San Fernando Dam. The dam and outlet works were reconstructed after the 1971 San Fernando Earthquake. In 1994, the dam underwent liquefaction upstream of the reconstructed berm. The pipe collapsed on the west side of the liquefied zone and a large sinkhole formed over the drain line. The failure of this drain line provides a unique opportunity to study the seismic response of buried drains and culverts.

  3. Corrosion failures of austenitic stainless steel piping

    SciTech Connect

    Louthan, M.R. Jr.

    1993-10-01

    The safe and efficient operation of many chemical/industrial systems requires the continued integrity of the process piping; this is achieved through a complex series of interactions influenced by design, fabrication, construction, operation, inspection and lay-up requirements. Potential material-enviroment interactions are frequently, if evaluated at all, relegated to secondary considerations. This tendency virtually assures corrosion induced degradation of the process piping systems. Pitting, crevice attack, stress cracking, microbiologically influenced corrosion, intergranular attack and corrosion fatigue have caused leaks, cracks, failures and shutdown of numerous process systems. This paper uses the lessons learned from failure analysis to emphasize the importance of an integrated material program to system success. The necessity of continuing evaluation if also emphasized through examples of failures which were associated with materials-environment interactions caused by slight alterations of processes and/or systems.

  4. Instrumented failure of hillslope models with soil-pipes

    NASA Astrophysics Data System (ADS)

    Sharma, Raj H.; Konietzky, Heinz

    2011-07-01

    Soil-pipes (porous pipes inside a hillslope) are often detected in collapsed slopes indicating their influence on slope failure processes. Only limited studies can be found regarding the impacts of soil-pipes on landslide mechanisms. Hillslope models prepared in a flume are experimented with different soil-pipe configurations: a) no pipe, b) closed pipe and c) open pipe. Pore-water pressures were measured at six different locations along a slope. Discharges at the outlet of soil-pipe and groundwater seepage were also recorded. For the above mentioned pipe configurations two types of experiments were conducted: a) rainfall-induced failure and b) seepage-induced failure. Experimental results show that a closed pipe accumulates water around its lower end and continuously increases pore-water pressure till a failure. An open pipe works as a means of hillslope drainage and reduces the pore-water pressure of an entire slope. However, if open pipe is blocked, pore-water pressure close to its lower end rises rapidly, leading to immediate soil mass movement. For both seepage and rainfall-induced failure experiments, the maximum pressure before the failure was larger at a slope with an open pipe (once it is closed) than a slope with a pipe closed from the beginning or that without a soil-pipe. This indicates that the blockage of soil-pipes makes a slope more susceptible to failure. Displacement vectors show that soil movement velocity close to the surface was highest at slopes with open pipes after closure and lowest at slopes without pipes because of a higher degree of saturation and pore-water pressure at the time of failure of the former. Before a large failure, small fluctuations in pore-water pressure were also observed which can be an indicator of impending failure.

  5. PVC (polyvinylchloride) pipe reliability and failure modes

    SciTech Connect

    Carroll, M.M.

    1984-06-01

    This report is narrowed to one variety of plastic pipe, polyvinylchloride (PVC), because of its common and extensive industrial, commercial and residential applications. There are certain disadvantages which must also be considered. PVC pipe is essentially brittle in nature, and it is relatively easily damaged by mechanical means such as being struck by tools or other materials; being weakened or fractured by gouging, abrasion or rough handling such as commonly occurs when pipe sections are thrown or walked on by workers. Excessive heat, welding slag, sunlight, and certain chemicals adversely affect it. There is also some concern about manufacturing processes which can affect product quality and integrity.

  6. Extension of pipe failure models to consider the absence of data from replaced pipes.

    PubMed

    Scheidegger, Andreas; Scholten, Lisa; Maurer, Max; Reichert, Peter

    2013-07-01

    Predictions of the expected number of failures of water distribution network pipes are important to develop an optimal management strategy. A number of probabilistic pipe failure models have been proposed in the literature for this purpose. They have to be calibrated on failure records. However, common data management practices mean that replaced pipes are often absent from available data sets. This leads to a 'survival selection bias', as pipes with frequent failures are more likely to be absent from the data. To address this problem, we propose a formal statistical approach to extend the likelihood function of a pipe failure model by a replacement model. Frequentist maximum likelihood estimation or Bayesian inference can then be applied for parameter estimation. This approach is general and is not limited to a particular failure or replacement model. We implemented this approach with a Weibull-exponential failure model and a simple constant probability replacement model. Based on this distribution assumptions, we illustrated our concept with two examples. First, we used simulated data to show how replacement causes a 'survival selection bias' and how to successfully correct for it. A second example with real data illustrates how a model can be extended to consider covariables.

  7. NASTRAN analysis of heat-transfer fluid fill pipe failure

    NASA Technical Reports Server (NTRS)

    Winter, J. R.

    1980-01-01

    An example that shows the difficulties of failure analyses and the advantage of the finite element method (NASTRAN) in assisting in determining the true cause of a failure is presented. In this example, cracks were developing along a pipe weld. After discarding several possible causes for the failures, it was finally determined that the problem was due to stress corrosion cracking associated with a rather unusual and novel environmental condition.

  8. 46 CFR 154.520 - Piping calculations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... allowable stress values under § 56.07-10 of this chapter and, if the design temperature is −110 °C (−166 °F) or lower, the stress analysis must be specially approved by the Commandant (CG-ENG) and must include: (a) Pipe weight loads; (b) Acceleration loads; (c) Internal pressure loads; (d) Thermal loads; and (e...

  9. 46 CFR 154.520 - Piping calculations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... allowable stress values under § 56.07-10 of this chapter and, if the design temperature is −110 °C (−166 °F) or lower, the stress analysis must be specially approved by the Commandant (CG-ENG) and must include: (a) Pipe weight loads; (b) Acceleration loads; (c) Internal pressure loads; (d) Thermal loads; and (e...

  10. Failure and factors of safety in piping system design

    SciTech Connect

    Antaki, G.A.

    1993-06-01

    An important body of test and performance data on the behavior of piping systems has led to an ongoing reassessment of the code stress allowables and their safety margin. The codes stress allowables, and their factors of safety, are developed from limits on the incipient yield (for ductile materials), or incipient rupture (for brittle materials), of a test specimen loaded in simple tension. In this paper, we examine the failure theories introduced in the B31 and ASME III codes for piping and their inherent approximations compared to textbook failure theories. We summarize the evolution of factors of safety in ASME and B31 and point out that, for piping systems, it is appropriate to reconsider the concept and definition of factors of safety.

  11. Reactor Materials Program process water piping indirect failure frequency

    SciTech Connect

    Daugherty, W.L.

    1989-10-30

    Following completion of the probabilistic analyses, the LOCA Definition Project has been subject to various external reviews, and as a result the need for several revisions has arisen. This report updates and summarizes the indirect failure frequency analysis for the process water piping. In this report, a conservatism of the earlier analysis is removed, supporting lower failure frequency estimates. The analysis results are also reinterpreted in light of subsequent review comments.

  12. Failure analysis of a Stirling engine heat pipe

    NASA Technical Reports Server (NTRS)

    Moore, Thomas J.; Cairelli, James E.; Khalili, Kaveh

    1989-01-01

    Failure analysis was conducted on a heat pipe from a Stirling Engine test rig which was designed to operate at 1073 K. Premature failure had occurred due to localized overheating at the leading edge of the evaporator fin. It was found that a crack had allowed air to enter the fin and react with the sodium coolant. The origin of the crack was found to be located at the inner surface of the Inconel 600 fin where severe intergranular corrosion had taken place.

  13. 46 CFR 56.35-1 - Pipe stress calculations (replaces 119.7).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Pipe stress calculations (replaces 119.7). 56.35-1... PIPING SYSTEMS AND APPURTENANCES Expansion, Flexibility and Supports § 56.35-1 Pipe stress calculations (replaces 119.7). (a) A summary of the results of pipe stress calculations for the main and auxiliary steam...

  14. 46 CFR 56.35-1 - Pipe stress calculations (replaces 119.7).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Pipe stress calculations (replaces 119.7). 56.35-1... PIPING SYSTEMS AND APPURTENANCES Expansion, Flexibility and Supports § 56.35-1 Pipe stress calculations (replaces 119.7). (a) A summary of the results of pipe stress calculations for the main and auxiliary steam...

  15. 46 CFR 56.35-1 - Pipe stress calculations (replaces 119.7).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Pipe stress calculations (replaces 119.7). 56.35-1... PIPING SYSTEMS AND APPURTENANCES Expansion, Flexibility and Supports § 56.35-1 Pipe stress calculations (replaces 119.7). (a) A summary of the results of pipe stress calculations for the main and auxiliary steam...

  16. 46 CFR 56.35-1 - Pipe stress calculations (replaces 119.7).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Pipe stress calculations (replaces 119.7). 56.35-1... PIPING SYSTEMS AND APPURTENANCES Expansion, Flexibility and Supports § 56.35-1 Pipe stress calculations (replaces 119.7). (a) A summary of the results of pipe stress calculations for the main and auxiliary steam...

  17. 46 CFR 56.35-1 - Pipe stress calculations (replaces 119.7).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Pipe stress calculations (replaces 119.7). 56.35-1... PIPING SYSTEMS AND APPURTENANCES Expansion, Flexibility and Supports § 56.35-1 Pipe stress calculations (replaces 119.7). (a) A summary of the results of pipe stress calculations for the main and auxiliary steam...

  18. Calculate nonfluidized flow in cyclone diplegs and transition pipes

    SciTech Connect

    Talavera, P.G.

    1995-12-01

    A new method to calculate nonfluidized flow of solid particles accounts for varying void fractions and angle of internal friction for different particle types. Thus, it is more accurate and flexible than existing empirical equations. Nonfluidized flow of solid particles is encountered frequently in the hydrocarbon processing industry. Cyclone diplegs in a FCCU reactor and regenerator is one area where the dense flow of solids is found. Sizing these lines to handle the dense flow of solids uses mainly empirical methods. Designers presently use rules of thumb and empirical equations to determine catalyst flow in pipes and cyclone diplegs. Rates are frequently expressed in flux rates with values ranging from 50 to 350 lb/sec-ft{sup 2}. But these empirical methods do not account for varying void fractions for different types of solids. Nonfluidized dense flow of solids through pipes can be broken into three areas. The first is solids flow into a pipe in nonhindered flow. An example of this is flow from a nonflooded cyclone dust bowl. The second area is solids flow into a pipe in hindered (friction) flow. An example of this is nonfluidized flow of solids from hoppers or from a flooded cyclone bowl. Core transport of solids in a pipe is third. An example of this is solids flow through a pipe with no restrictions.

  19. Size safety valve discharge piping with a programmable calculator

    SciTech Connect

    D'ambra, A.

    1982-10-01

    Discussed is a program that will aid in the proper sizing of steam safety valve discharge piping frequently encountered in steam distribution systems. Basis for calculation is the ASME/ANSI Power Piping Code. Code reference is not necessary for running the program. Presented is a safety valve installation schematic, the program listing, data registers, constants, and a sample problem. The calculation done by this program is a fluid momentum check to assure that selected pipe sizes yield velocities and back pressures such that the steam blowing out of the safety valve is driven up the stack and not backwards out of the clearance. Back pressure should not exceed safety valve manufacturers' limits to realize full design capacity of the installation.

  20. S Tank Farm SL-119 saltwell piping failure analysis report

    SciTech Connect

    Carlos, W.C.

    1994-08-05

    On January 24, 1992, while pressure testing saltwell line SL-119 in the 241-S Tank Farm, water was observed spraying out of heat trace enclosure. The SL-115, SL-116, SN-215, and SN-216 saltwell lines also recently failed pressure testing because of leaks. This study documents the pertinent facts about the SL-119 line and discusses the cause of the failures. The inspection of the SL-119 failure revealed two through-the-wall holes in the top center of the pipeline. The inspection also strongly suggests that the heat tracing system is directly responsible for causing the SL-119 failure. Poor design of the heat tracing system allowed water to enter, condense, and collect in the electric metallic tubing (EMT) carbon steel conduits. Water flowed to the bottom of the elbow of the conduit and corroded out the elbow. The design also allowed drifting desert sand to enter into the conduit and fall to the bottom (elbow) of the conduit. The sand became wet and aided in the corrosion of the elbow of the conduit. After the EMT conduits corroded though, the water dripped from the corroded ends of the EMT conduits onto the top of the saltwell pipe, corroding the two holes into the top of the line. If the heat tracing hot splice box had not allowed moisture to enter the EMT conduits, the saltwell piping would not have corroded and caused SL-119 to fail.

  1. Probabilistic analyses of failure in reactor coolant piping. [Double-ended guillotine break

    SciTech Connect

    Holman, G.S.

    1984-07-20

    LLNL is performing probabilistic reliability analyses of PWR and BWR reactor coolant piping for the NRC Office of Nuclear Regulatory Research. Specifically, LLNL is estimating the probability of a double-ended guillotine break (DEGB) in the reactor coolant loop piping in PWR plants, and in the main stream, feedwater, and recirculation piping of BWR plants. In estimating the probability of DEGB, LLNL considers two causes of pipe break: pipe fracture due to the growth of cracks at welded joints (direct DEGB), and pipe rupture indirectly caused by the seismically-induced failure of critical supports or equipment (indirect DEGB).

  2. Could Acoustic Emission Testing Show a Pipe Failure in Advance?

    NASA Astrophysics Data System (ADS)

    Soares, S. D.; Teixeira, J. C. G.

    2004-02-01

    During the last 20 years PETROBRAS has been attempting to use Acoustic Emission (AE) as an inspection tool. In this period the AE concept has changed from a revolutionary method to a way of finding areas to make a complete inspection. PETROBRAS has a lot of pressure vessels inspected by AE and with other NDTs techniques to establish their relationship. In other hand, PETROBRAS R&D Center has conducted destructive hydrostatic tests in pipelines samples with artificial defects made by milling. Those tests were monitored by acoustic emission and manual ultrasonic until the complete failure of pipe sample. This article shows the results obtained and a brief proposal of analysis criteria for this environment of test.

  3. Predicting the Probability of Failure of Cementitious Sewer Pipes Using Stochastic Finite Element Method.

    PubMed

    Alani, Amir M; Faramarzi, Asaad

    2015-06-10

    In this paper, a stochastic finite element method (SFEM) is employed to investigate the probability of failure of cementitious buried sewer pipes subjected to combined effect of corrosion and stresses. A non-linear time-dependant model is used to determine the extent of concrete corrosion. Using the SFEM, the effects of different random variables, including loads, pipe material, and corrosion on the remaining safe life of the cementitious sewer pipes are explored. A numerical example is presented to demonstrate the merit of the proposed SFEM in evaluating the effects of the contributing parameters upon the probability of failure of cementitious sewer pipes. The developed SFEM offers many advantages over traditional probabilistic techniques since it does not use any empirical equations in order to determine failure of pipes. The results of the SFEM can help the concerning industry (e.g., water companies) to better plan their resources by providing accurate prediction for the remaining safe life of cementitious sewer pipes.

  4. Failure probability of PWR reactor coolant loop piping. [Double-ended guillotine break

    SciTech Connect

    Lo, T.; Woo, H.H.; Holman, G.S.; Chou, C.K.

    1984-02-01

    This paper describes the results of assessments performed on the PWR coolant loop piping of Westinghouse and Combustion Engineering plants. For direct double-ended guillotine break (DEGB), consideration was given to crack existence probability, initial crack size distribution, hydrostatic proof test, preservice inspection, leak detection probability, crack growth characteristics, and failure criteria based on the net section stress failure and tearing modulus stability concept. For indirect DEGB, fragilities of major component supports were estimated. The system level fragility was then calculated based on the Boolean expression involving these fragilities. Indirect DEGB due to seismic effects was calculated by convolving the system level fragility and the seismic hazard curve. The results indicate that the probability of occurrence of both direct and indirect DEGB is extremely small, thus, postulation of DEGB in design should be eliminated and replaced by more realistic criteria.

  5. Fatigue life calculation of desuperheater for solving pipe cracking issue using finite element method (FEM) software

    NASA Astrophysics Data System (ADS)

    Kumar, Aravinda; Singh, Jeetendra Kumar; Mohan, K.

    2012-06-01

    Desuperheater assembly experiences thermal cycling in operation by design. During power plant's start up, load change and shut down, thermal gradient is highest. Desuperheater should be able to handle rapid ramp up or ramp down of temperature in these operations. With "hump style" two nozzle desuperheater, cracks were appearing in the pipe after only few cycles of operation. From the field data, it was clear that desuperheater is not able to handle disproportionate thermal expansion happening in the assembly during temperature ramp up and ramp down in operation and leading to cracks appearing in the piping. Growth of thermal fatigue crack is influenced by several factors including geometry, severity of thermal stress and applied mechanical load. This paper seeks to determine cause of failure of two nozzle "hump style" desuperheater using Finite Element Method (FEM) simulation technique. Thermal stress simulation and fatigue life calculation were performed using commercial FEA software "ANSYS" [from Ansys Inc, USA]. Simulation result showed that very high thermal stress is developing in the region where cracks are seen in the field. From simulation results, it is also clear that variable thermal expansion of two nozzle studs is creating high stress at the water manifold junction. A simple and viable solution is suggested by increasing the length of the manifold which solved the cracking issues in the pipe.

  6. Determination of Secondary Encasement Pipe Design Pressure

    SciTech Connect

    TEDESCHI, A.R.

    2000-10-26

    This document published results of iterative calculations for maximum tank farm transfer secondary pipe (encasement) pressure upon failure of the primary pipe. The maximum pressure was calculated from a primary pipe guillotine break. Results show encasement pipeline design or testing pressures can be significantly lower than primary pipe pressure criteria.

  7. Project W-320, 241-C-106 sluicing: Piping calculations. Volume 4

    SciTech Connect

    Bailey, J.W.

    1998-07-24

    This supporting document has been prepared to make the FDNW calculations for Project W-320 readily retrievable. The objective of this calculation is to perform the structural analysis of the Pipe Supports designed for Slurry and Supernate transfer pipe lines in order to meet the requirements of applicable ASME codes. The pipe support design loads are obtained from the piping stress calculations W320-27-I-4 and W320-27-I-5. These loads are the total summation of the gravity, pressure, thermal and seismic loads. Since standard typical designs are used for each type of pipe support such as Y-Stop, Guide and Anchors, each type of support is evaluated for the maximum loads to which this type of supports are subjected. These loads are obtained from the AutoPipe analysis and used to check the structural adequacy of these supports.

  8. Project W-320, 241-C-106 sluicing: Piping calculations. Volume 2

    SciTech Connect

    Bailey, J.W.

    1998-07-25

    This supporting document has been prepared to make the FDNW calculations for Project W-320 readily retrievable. The objectives of this calculation are (1) To perform static and Safety Class 2 dynamic stress analysis of the Slurry and Supernate Process (inner) piping connecting Tanks 241-C-106 and 241-AY-102 in order to be in compliance with the Code requirements; (2) To assure the thermal expansion of the process pipe not be strained by the outer encasement pipe; and (3) To furnish process pipe support to the Civil Engineering group.

  9. Parametric calculations of fatigue-crack growth in piping. [PWR; BWR

    SciTech Connect

    Simonen, F.A.; Goodrich, C.W.

    1983-03-01

    A major objective of this program is to provide data that can be used to formulate recommended revisions to ASME Section XI and regulatory requirements for inservice inspection of piping and pressure vessels. This study presents calculations of the growth of piping flaws produced by fatigue. Flaw growth was predicted as a function of the initial flaw size, the level and number of stress cycles, the piping material, and environmental factors.

  10. Pipe Axial Flaw Failure Criteria (PAFFC): Version 1.0 user`s manual and software

    SciTech Connect

    Leis, B.N.; Ghadiali, N.D.

    1994-05-04

    This topical report is the technical manual and basis for delivery of the software tided Pipe Axial Flaw Failure Criterion. This criterion was developed under SI Task 1. 13 for the Line Pipe Research Supervisory Committee of the Pipeline Research Committee. This software has been given the acronym PAFFC, which follows from the underlined letters in the title for this code. The purpose of PAFFC is to determine the failure conditions associated with a single external axial flaw in a gas transmission pipeline. Failure is determined concurrently in terms of two independent failure processes - fracture and/or net-section (plastic) collapse of the ligament between the flaw and the inside surface of the pipe.

  11. Beam and shell modes of buckling of buried pipes induced by compressive ground failure

    SciTech Connect

    Chiou, Y.J.; Chi, S.Y.

    1995-12-31

    The buckling of buried pipeline induced by compressive ground failure was investigated. Both the beam mode of buckling and local shell mode of buckling, and their interactions were studied. The pipeline response was analyzed numerically. The results agree qualitatively with past researches and possess satisfactory comparisons with actual case histories. The relations of critical buried depth versus ratio of pipe diameter to thickness for buried pipe with different imperfections and various soil foundations were established.

  12. Predicting the Probability of Failure of Cementitious Sewer Pipes Using Stochastic Finite Element Method

    PubMed Central

    Alani, Amir M.; Faramarzi, Asaad

    2015-01-01

    In this paper, a stochastic finite element method (SFEM) is employed to investigate the probability of failure of cementitious buried sewer pipes subjected to combined effect of corrosion and stresses. A non-linear time-dependant model is used to determine the extent of concrete corrosion. Using the SFEM, the effects of different random variables, including loads, pipe material, and corrosion on the remaining safe life of the cementitious sewer pipes are explored. A numerical example is presented to demonstrate the merit of the proposed SFEM in evaluating the effects of the contributing parameters upon the probability of failure of cementitious sewer pipes. The developed SFEM offers many advantages over traditional probabilistic techniques since it does not use any empirical equations in order to determine failure of pipes. The results of the SFEM can help the concerning industry (e.g., water companies) to better plan their resources by providing accurate prediction for the remaining safe life of cementitious sewer pipes. PMID:26068092

  13. New Formulas for Calculating the Fluid Flow Characteristics in a Circular Pipe

    NASA Astrophysics Data System (ADS)

    Chesnokov, Yu. G.

    2017-07-01

    We propose new formulas for calculating the friction factor in pipes with smooth walls and relations between the mean and the maximum fluid flow velocity in a pipe. The formulas are in better agreement with experimental data than the literature relations. An expression for the friction factor suitable for all flow conditions is proposed. The results of this work can be used in calculating the hydraulic resistance of pipes, as well as in calculating the heat and mass transfer processes in apparatuses incorporating tubular elements.

  14. Failures Analysis of E-Glass Fibre reinforced pipes in Oil and Gas Industry: A Review

    NASA Astrophysics Data System (ADS)

    Bobba, Sujith; Leman, Z.; Zainuddin, E. S.; Sapuan, S. M.

    2017-07-01

    A comprehensive review is conducted on the failures in the field of manufacturing and installation of E-glass fiber reinforced pipes (GFRP). Some of the failures which are mainly encountered after the installation of E-Glass fiber reinforced pipes are the for nation of air bubbles in between the polyester resin layer and the surface film, dispersion of moisture in between the tubing outer and inner layers after installation, heat released in between the layers of E-glass fiber reinforced pipes due to exothermic reaction which in turn results in the formation of cracks on the surface of the pipe. The recent findings and challenges performed in conducting research regarding the deterioration caused in glass fiber reinforced pipes are highlighted and each type of failure that was identified was illustrated with an appropriate high resolution photograph. Performing creep resistance and fatigue analysis are new aspects which are still requited to be analyzed which ave not been stated in the literature which are nominated.

  15. Vacuum Bellows, Vacuum Piping, Cryogenic Break, and Copper Joint Failure Rate Estimates for ITER Design Use

    SciTech Connect

    L. C. Cadwallader

    2010-06-01

    The ITER international project design teams are working to produce an engineering design in preparation for construction of the International Thermonuclear Experimental Reactor (ITER) tokamak. During the course of this work, questions have arisen in regard to safety barriers and equipment reliability as important facets of system design. The vacuum system designers have asked several questions about the reliability of vacuum bellows and vacuum piping. The vessel design team has asked about the reliability of electrical breaks and copper-copper joints used in cryogenic piping. Research into operating experiences of similar equipment has been performed to determine representative failure rates for these components. The following chapters give the research results and the findings for vacuum system bellows, power plant stainless steel piping (amended to represent vacuum system piping), cryogenic system electrical insulating breaks, and copper joints.

  16. Investigation of a Modified 9Cr-1Mo (P91) Pipe Failure

    SciTech Connect

    Klueh, Ronald L; Shingledecker, John P

    2006-04-01

    A modified 9Cr-1Mo feedwater (condensate) line at an Eastman Chemical Company plant failed in January 2005. The line was in continuous service since start-up December 2001 until failure. The Plant Superintendent estimated there were three thermal cycles since start-up, although there may have been as many as 25 thermal cycles during commissioning. Normal operating temperature was 325 F (163 C) and pressure was 1762 psig. The line was steam traced with the tracing activated only when ambient outdoor temperature dropped to 40 F (5 C). A modified 9Cr-1Mo steel (P91) pipe failure in a feedwater line in a chemical plant was investigated. The failure occurred in the vicinity of an elbow produced with socket welds of the pipe to the elbow. Based on metallography and hardness measurements, it was concluded that failure occurred because of an improper post-weld heat treatment of the socket weldment.

  17. An analysis of molten-corium-induced failure of drain pipes in BWR Mark 2 containments

    SciTech Connect

    Taleyarkhan, R.P. ); Podowski, M.Z. )

    1991-01-01

    This study has focused on mechanistic simulation and analysis of potential failure modes for inpedestal drywell drain pipes in the Limerick boiling water reactor (BWR) Mark 2 containment. Physical phenomena related to surface tension breakdown, heatup, melting, ablation, crust formation and failure, and core material relocation into drain pipes with simultaneous melting of pipe walls were modeled and analyzed. The results of analysis have been used to assess the possibility of drain pipe failure and the resultant loss of pressure-suppression capability. Estimates have been made for the timing and amount of molten corium released to the wetwell. The study has revealed that significantly different melt progression sequences can result depending upon the failure characteristics of the frozen metallic crust which forms over the drain cover during the initial stages of debris pour. Another important result is that it can take several days for the molten fuel to ablate the frozen metallic debris layer -- if the frozen layer has cooled below 1100 K before fuel attack. 10 refs., 3 figs., 4 tabs.

  18. Failure mechanisms and lifetime prediction methodology for polybutylene pipe in water distribution system

    NASA Astrophysics Data System (ADS)

    Niu, Xiqun

    Polybutylene (PB) is a semicrystalline thermoplastics. It has been widely used in potable water distribution piping system. However, field practice shows that failure occurs much earlier than the expected service lifetime. What are the causes and how to appropriately evaluate its lifetime motivate this study. In this thesis, three parts of work have been done. First is the understanding of PB, which includes material thermo and mechanical characterization, aging phenomena and notch sensitivity. The second part analyzes the applicability of the existing lifetime testing method for PB. It is shown that PB is an anomaly in terms of the temperature-lifetime relation because of the fracture mechanism transition across the testing temperature range. The third part is the development of the methodology of lifetime prediction for PB pipe. The fracture process of PB pipe consists of three stages, i.e., crack initiation, slow crack growth (SCG) and crack instability. The practical lifetime of PB pipe is primarily determined by the duration of the first two stages. The mechanism of crack initiation and the quantitative estimation of the time to crack initiation are studied by employing environment stress cracking technique. A fatigue slow crack growth testing method has been developed and applied in the study of SCG. By using Paris-Erdogan equation, a model is constructed to evaluate the time for SCG. As a result, the total lifetime is determined. Through this work, the failure mechanisms of PB pipe has been analyzed and the lifetime prediction methodology has been developed.

  19. Pitting failure of copper pipings for emergency fire sprinkler in ground water

    NASA Astrophysics Data System (ADS)

    Baek, Seung-won; Lee, Jong-kwon; Kim, Jong-jip; Kim, Kyung-ja

    2015-05-01

    The possibility of microbiologically influenced corrosion was investigated in the early pitted copper pipes. The pipes were installed for less than 6 months as an immergency fire sprinkler. The bacteria were cultured by sampling of corrosion by-product near pits on failed copper pipes for the aerobic as well as anaerobic bacteria. However, only aerobic bacteria was found, which were Micrococcus Luteus and Bacillus sp.. The corrosion rate of copper pipes were studied by weight loss in the groundwater and polarization method. In immersion test as well as the electrochemical polarization test in ground water, only Micrococcus Luteus could activate corrosion of copper by 20% and 15%, respectively. On the other hand, Bacillus sp. showed little effect on corrosion in the above two tests. The shape and characteristics of failed copper pipes as well as simulated copper were investigated using stereoscope, optical microscopy, scanning electron microscope and EDS. The cause of pits were discussed, related with the dissolved copper concentrations, pH, and optical density. It could be concluded that the early failure of copper pipings could be ascribed to the acceration of copper in the presence of bacteria, i.e., Micrococcus Luteus.

  20. Report: Identification of root cause failure of piping in a service water system

    SciTech Connect

    Lutey, R.W.; Mason, P.D.

    1994-12-31

    This report deals with studies on the identification of the root cause of piping failures in a service water system, and to develop a proposal for action to prevent further failures. The failures were characterized as pin hole through-wall penetrations associated with butt-welds, restricted to stagnant flow carbon steel piping. Based on extensive tests, inspections and observations the conclusions presented in this report are summarized as follows: (1) the pin hole failures were characterized as root cause, microbiologically influenced corrosion (MIC), this conclusion was based upon microbiological, visual, and chemical testing at the as-is site of a recent failure, pipe segments were available for extensive testing and comparison to previous failures; (2) failures were isolated to stagnant sites at points where poor weld penetration provided optimum conditions for MIC to occur; (3) extensive examination of the process flow and intermittent flow sites characterized as high risk areas were made, no evidence of microbiological involvement with corrosion was found, no evidence of any type of significant pitting corrosion was found at these sites; (4) removal and replacement of stagnant line and weld sites was done as a major step in preventing further failures. MIC inoculum, primarily anaerobic microorganisms, was found at many anaerobic and aerobic sites in the system. This suggested that a preventive chemical treatment program would be appropriate to maintain the system at a MIC free status. A monitoring program was suggested to assess on a real-time-basis, the potential for MIC and to monitor the mitigation of MIC.

  1. Failure Analysis of PRDS Pipe in a Thermal Power Plant Boiler

    NASA Astrophysics Data System (ADS)

    Ghosh, Debashis; Ray, Subrata; Mandal, Jiten; Mandal, Nilrudra; Shukla, Awdhesh Kumar

    2016-06-01

    The pressure reducer desuperheater (PRDS) pipeline is used for reducing the pressure and desuperheating of the steam in different auxiliary pipeline. When the PRDS pipeline is failed, the reliability of the boiler is affected. This paper investigates the probable cause/causes of failure of the PRDS tapping line. In that context, visual inspection, outside diameter and wall thickness measurement, chemical analysis, metallographic examination and hardness measurement are conducted as part of the investigative studies. Apart from these tests, mechanical testing and fractographic analysis are also conducted as supplements. Finally, it has been concluded that the PRDS pipeline has mainly failed due to graphitization due to prolonged exposure of the pipe at higher temperature. The improper material used is mainly responsible for premature failure of the pipe.

  2. Wave path calculation for phased array imaging to evaluate weld zone of elbow pipes (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Park, Choon-Su; Park, Jin Kyu; Choi, Wonjae; Cho, Seunghyun; Kim, Dong-Yeol; Han, Ki Hyung

    2017-04-01

    It has long been non-destructively evaluated on weld joints of various pipes which are indispensable to most of industrial structures. Ultrasound evaluation has been used to detect flaws in welding joints, but some technical deficiencies still remain. Especially, ultrasound imaging on weld of elbow pipes has many challenging issues due to varying surface along circumferential direction. Conventional ultrasound imaging has particularly focused on ultrasonic wave propagation based on ray theory. This confines the incident angle and the position of an array transducer as well. Total focusing method (TFM), however, can provide not only high resolution images but also flexibility that enables to use ultrasonic waves to every direction that they can reach. This leads us to develop a method to get images of weld zone from an elbow part that curves. It is inevitable of each ultrasonic wave from the array transducer to transmit through different media and to be reflected from the boundary with angles along the curved surface. To form a correct PA image, careful calculation is made to ensure that time delay of receive-after-transmit is correctly shifted and summed even under non-planar boundary condition. Here, a method to calculate wave paths for the zone of interest at weld joint of an elbow pipe is presented. Numerical simulations of wave propagation on an elbow pipe are made to verify the proposed method. It is also experimentally demonstrated that the proposed method is well applied to various actual pipes that contains artificial flaws with a flexible wedge.

  3. Qualification of a Method to Calculate the Irrecoverable Pressure Loss in High Reynolds Number Piping Systems

    SciTech Connect

    Sigg, K. C.; Coffield, R. D.

    2002-09-01

    High Reynolds number test data has recently been reported for both single and multiple piping elbow design configurations at earlier ASME Fluid Engineering Division conferences. The data of these studies ranged up to a Reynolds number of 42 x 10[sup]6 which is significantly greater than that used to establish design correlations before the data was available. Many of the accepted design correlations, based on the lower Reynolds number data, date back as much as fifty years. The new data shows that these earlier correlations are extremely conservative for high Reynolds number applications. Based on the recent high Reynolds number information a new recommended method has been developed for calculating irrecoverable pressure loses in piping systems for design considerations such as establishing pump sizing requirements. This paper describes the recommended design approach and additional testing that has been performed as part of the qualification of the method. This qualification testing determined the irrecoverable pressure loss of a piping configuration that would typify a limiting piping section in a complicated piping network, i.e., multiple, tightly coupled, out-of-plane elbows in series under high Reynolds number flow conditions. The overall pressure loss measurements were then compared to predictions, which used the new methodology to assure that conservative estimates for the pressure loss (of the type used for pump sizing) were obtained. The recommended design methodology, the qualification testing and the comparison between the predictions and the test data are presented. A major conclusion of this study is that the recommended method for calculating irrecoverable pressure loss in piping systems is conservative yet significantly lower than predicted by early design correlations that were based on the extrapolation of low Reynolds number test data.

  4. Research for different crack width calculation methods of concrete-lined steel pressure pipe

    NASA Astrophysics Data System (ADS)

    Xu, Chuang; Li, Yang

    2017-08-01

    Based on a certain threshold to ensure the durability of structure, the concrete-lined steel pressure pipes used in the structure of large hydropower station widely are allowed to exist in concrete cracking under the action of a certain hydraulic pressure. According to the 1:2 large scale experiment model and the measured data of Three Gorges Hydro-power Station, the existing different methods for calculating crack width were compared and improvements and crack control measures were raised.

  5. Statistical failure models for water distribution pipes - A review from a unified perspective.

    PubMed

    Scheidegger, Andreas; Leitão, João P; Scholten, Lisa

    2015-10-15

    This review describes and compares statistical failure models for water distribution pipes in a systematic way and from a unified perspective. The way the comparison is structured provides the information needed by scientists and practitioners to choose a suitable failure model for their specific needs. The models are presented in a novel framework consisting of: 1) Clarification of model assumptions. The models originally formulated in different mathematical forms are all presented as failure rate. This enables to see differences and similarities across the models. Furthermore, we present a new conceptual failure rate that an optimal model would represent and to which the failure rate of each model can be compared. 2) Specification of the detailed data assumptions required for unbiased model calibration covering the structure and completeness of the data. 3) Presentation of the different types of probabilistic predictions available for each model. Nine different models and their variations or further developments are presented in this review. For every model an overview of its applications published in scientific journals and the available software implementations is provided. The unified view provides guidance to model selection. Furthermore, the model comparison presented herein enables to identify areas where further research is needed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Numerical simulation and factor analysis of petrochemical pipe erosion-corrosion failure

    NASA Astrophysics Data System (ADS)

    XU, G. F.; OU, G. F.; Chen, T.; Li, P. X.; JIN, H. Z.

    2016-05-01

    Based on the behavior of carbon steel outlet tube in REAC pipes of Zhenhai Refining & Chemical Company, the mathematical model of fluid-solid interaction was established according to the mechanism of erosion-corrosion damage. The interaction between corrosion products protecting film and multiphase liquid was analyzed by numerical simulation method. The distribution of shearing stress on the inwall of elbow bend, and the distribution of principal displacement, stress and strain of corrosion products protecting film were disclosed, while the erosion-corrosion failure processes was studied. The simulation result coincides with that of the positioned thickness gauging which validated the reliability and feasibility of the finite element analysis software simulation method. The obtained results can be used in the erosion-corrosion failure analysis, structural optimization, in-service testing positioning, life prediction, risk assessment, safety and other security projects for multiphase flow pipeline.

  7. Experimental measurement, calculation and thermal visualization condenser temperature of cooling device with a heat pipe technology

    NASA Astrophysics Data System (ADS)

    Nemec, Patrik; Malcho, Milan; Kaduchová, Katarína

    This work deal with evaluation of condenser temperature by experimental measurement, calculation and thermal visualization of cooling device working with a heat pipe technology. The referred device in the article is cooling device capable transfer high heat fluxes from electric elements to the surrounding. One from many things influenced the heat flux amount transferred from electronic elements through the cooling device to the surrounding is condenser construction, its capacity and option of heat removal. The work contain description, working principle and construction of cooling device. Experimental part describe the measuring method and mathematical calculation to condenser temperature evaluation of cooling device depending on the loaded heat of electronic components in range from 250 to 750 W. The mathematical calculation is based on physical phenomena of boiling, condensation and natural convection heat transfer. The results of experimental measurement and mathematical calculation are verified by thermal imagining of device condenser by IR camera.

  8. Effects of river reach discretization on the estimation of the probability of levee failure owing to piping

    NASA Astrophysics Data System (ADS)

    Mazzoleni, Maurizio; Brandimarte, Luigia; Barontini, Stefano; Ranzi, Roberto

    2014-05-01

    Over the centuries many societies have preferred to settle down nearby floodplains area and take advantage of the favorable environmental conditions. Due to changing hydro-meteorological conditions, over time, levee systems along rivers have been raised to protect urbanized area and reduce the impact of floods. As expressed by the so called "levee paradox", many societies might to tend to trust these levee protection systems due to an induced sense of safety and, as a consequence, invest even more in urban developing in levee protected flood prone areas. As a result, considering also the increasing number of population around the world, people living in floodplains is growing. However, human settlements in floodplains are not totally safe and have been continuously endangered by the risk of flooding. In fact, failures of levee system in case of flood event have also produced the most devastating disasters of the last two centuries due to the exposure of the developed floodprone areas to risk. In those cases, property damage is certain, but loss of life can vary dramatically with the extent of the inundation area, the size of the population at risk, and the amount of warning time available. The aim of this study is to propose an innovative methodology to estimate the reliability of a general river levee system in case of piping, considering different sources of uncertainty, and analyze the influence of different discretization of the river reach in sub-reaches in the evaluation of the probability of failure. The reliability analysis, expressed in terms of fragility curve, was performed evaluating the probability of failure, conditioned by a given hydraulic load in case of a certain levee failure mechanism, using a Monte Carlo and First Order Reliability Method. Knowing the information about fragility curve for each discrete levee reach, different fragility indexes were introduced. Using the previous information was then possible to classify the river into sub

  9. Calculation of Local Stress and Fatigue Resistance due to Thermal Stratification on Pressurized Surge Line Pipe

    NASA Astrophysics Data System (ADS)

    Bandriyana, B.; Utaja

    2010-06-01

    Thermal stratification introduces thermal shock effect which results in local stress and fatique problems that must be considered in the design of nuclear power plant components. Local stress and fatique calculation were performed on the Pressurize Surge Line piping system of the Pressurize Water Reactor of the Nuclear Power Plant. Analysis was done on the operating temperature between 177 to 343° C and the operating pressure of 16 MPa (160 Bar). The stagnant and transient condition with two kinds of stratification model has been evaluated by the two dimensional finite elements method using the ANSYS program. Evaluation of fatigue resistance is developed based on the maximum local stress using the ASME standard Code formula. Maximum stress of 427 MPa occurred at the upper side of the top half of hot fluid pipe stratification model in the transient case condition. The evaluation of the fatigue resistance is performed on 500 operating cycles in the life time of 40 years and giving the usage value of 0,64 which met to the design requirement for class 1 of nuclear component. The out surge transient were the most significant case in the localized effects due to thermal stratification.

  10. Calculation of Local Stress and Fatigue Resistance due to Thermal Stratification on Pressurized Surge Line Pipe

    SciTech Connect

    Bandriyana, B.; Utaja

    2010-06-22

    Thermal stratification introduces thermal shock effect which results in local stress and fatigue problems that must be considered in the design of nuclear power plant components. Local stress and fatigue calculation were performed on the Pressurize Surge Line piping system of the Pressurize Water Reactor of the Nuclear Power Plant. Analysis was done on the operating temperature between 177 to 343 deg. C and the operating pressure of 16 MPa (160 Bar). The stagnant and transient condition with two kinds of stratification model has been evaluated by the two dimensional finite elements method using the ANSYS program. Evaluation of fatigue resistance is developed based on the maximum local stress using the ASME standard Code formula. Maximum stress of 427 MPa occurred at the upper side of the top half of hot fluid pipe stratification model in the transient case condition. The evaluation of the fatigue resistance is performed on 500 operating cycles in the life time of 40 years and giving the usage value of 0,64 which met to the design requirement for class 1 of nuclear component. The out surge transient were the most significant case in the localized effects due to thermal stratification.

  11. On the calculation of turbulent heat transport downstream from an abrupt pipe expansion

    NASA Technical Reports Server (NTRS)

    Chieng, C. C.; Launder, B. E.

    1980-01-01

    A numerical study of flow and heat transfer in the separated flow region produced by an abrupt pipe explosion is reported, with emphasis on the region in the immediate vicinity of the wall where turbulent transport gives way to molecular conduction and diffusion. The analysis is based on a modified TEACH-2E program with the standard k-epsilon model of turbulence. Predictions of the experimental data of Zemanick and Dougall (1970) for a diameter ratio of 0.54 show generally encouraging agreement with experiment. At a diameter ratio of 0.43 different trends are discernable between measurement and calculation, though this appears to be due to effects unconnected with the wall region studied here.

  12. Performance and Reliability Analysis of Water Distribution Systems under Cascading Failures and the Identification of Crucial Pipes

    PubMed Central

    Shuang, Qing; Zhang, Mingyuan; Yuan, Yongbo

    2014-01-01

    As a mean of supplying water, Water distribution system (WDS) is one of the most important complex infrastructures. The stability and reliability are critical for urban activities. WDSs can be characterized by networks of multiple nodes (e.g. reservoirs and junctions) and interconnected by physical links (e.g. pipes). Instead of analyzing highest failure rate or highest betweenness, reliability of WDS is evaluated by introducing hydraulic analysis and cascading failures (conductive failure pattern) from complex network. The crucial pipes are identified eventually. The proposed methodology is illustrated by an example. The results show that the demand multiplier has a great influence on the peak of reliability and the persistent time of the cascading failures in its propagation in WDS. The time period when the system has the highest reliability is when the demand multiplier is less than 1. There is a threshold of tolerance parameter exists. When the tolerance parameter is less than the threshold, the time period with the highest system reliability does not meet minimum value of demand multiplier. The results indicate that the system reliability should be evaluated with the properties of WDS and the characteristics of cascading failures, so as to improve its ability of resisting disasters. PMID:24551102

  13. Performance and reliability analysis of water distribution systems under cascading failures and the identification of crucial pipes.

    PubMed

    Shuang, Qing; Zhang, Mingyuan; Yuan, Yongbo

    2014-01-01

    As a mean of supplying water, Water distribution system (WDS) is one of the most important complex infrastructures. The stability and reliability are critical for urban activities. WDSs can be characterized by networks of multiple nodes (e.g. reservoirs and junctions) and interconnected by physical links (e.g. pipes). Instead of analyzing highest failure rate or highest betweenness, reliability of WDS is evaluated by introducing hydraulic analysis and cascading failures (conductive failure pattern) from complex network. The crucial pipes are identified eventually. The proposed methodology is illustrated by an example. The results show that the demand multiplier has a great influence on the peak of reliability and the persistent time of the cascading failures in its propagation in WDS. The time period when the system has the highest reliability is when the demand multiplier is less than 1. There is a threshold of tolerance parameter exists. When the tolerance parameter is less than the threshold, the time period with the highest system reliability does not meet minimum value of demand multiplier. The results indicate that the system reliability should be evaluated with the properties of WDS and the characteristics of cascading failures, so as to improve its ability of resisting disasters.

  14. Simulations of the pipe overpack to compute constitutive model parameters for use in WIPP room closure calculations.

    SciTech Connect

    Park, Byoung Yoon; Hansen, Francis D.

    2004-07-01

    The regulatory compliance determination for the Waste Isolation Pilot Plant includes the consideration of room closure. Elements of the geomechanical processes include salt creep, gas generation and mechanical deformation of the waste residing in the rooms. The WIPP was certified as complying with regulatory requirements based in part on the implementation of room closure and material models for the waste. Since the WIPP began receiving waste in 1999, waste packages have been identified that are appreciably more robust than the 55-gallon drums characterized for the initial calculations. The pipe overpack comprises one such waste package. This report develops material model parameters for the pipe overpack containers by using axisymmetrical finite element models. Known material properties and structural dimensions allow well constrained models to be completed for uniaxial, triaxial, and hydrostatic compression of the pipe overpack waste package. These analyses show that the pipe overpack waste package is far more rigid than the originally certified drum. The model parameters developed in this report are used subsequently to evaluate the implications to performance assessment calculations.

  15. UQ and V&V techniques applied to experiments and simulations of heated pipes pressurized to failure

    SciTech Connect

    Romero, Vicente Jose; Dempsey, J. Franklin; Antoun, Bonnie R.

    2014-05-01

    This report demonstrates versatile and practical model validation and uncertainty quantification techniques applied to the accuracy assessment of a computational model of heated steel pipes pressurized to failure. The Real Space validation methodology segregates aleatory and epistemic uncertainties to form straightforward model validation metrics especially suited for assessing models to be used in the analysis of performance and safety margins. The methodology handles difficulties associated with representing and propagating interval and/or probabilistic uncertainties from multiple correlated and uncorrelated sources in the experiments and simulations including: material variability characterized by non-parametric random functions (discrete temperature dependent stress-strain curves); very limited (sparse) experimental data at the coupon testing level for material characterization and at the pipe-test validation level; boundary condition reconstruction uncertainties from spatially sparse sensor data; normalization of pipe experimental responses for measured input-condition differences among tests and for random and systematic uncertainties in measurement/processing/inference of experimental inputs and outputs; numerical solution uncertainty from model discretization and solver effects.

  16. Development of an alternative failure criterion for residual strength of corrosion defects in moderate- to high-toughness pipe. Final report

    SciTech Connect

    Stephens, D.R.; Leis, B.N.; Kurre, M.D.; Rudland, D.L.

    1999-01-01

    Under sponsorship of the Line Pipe Research Supervisory Committee of PRC International, Battelle has conducted ongoing research on the fundamental mechanisms driving failure of pipeline corrosion defects. This phase of the research investigation has resulted in a simplified, closed-form failure criterion for blunt corrosion, known as PCORRC. This report summarizes the key elements of recent research including: (1) development of a PC-software computational model, known as PCORR, for predicting the remaining strength of the class of corrosion defects that fail by ductile plastic-collapse under internal pressure loading; (2) a comparative evaluation of the material and defect geometry variables that control the remaining strength of blunt corrosion defects in moderate- to high-toughness pipe materials; (3) development of the simplified failure criterion, PCORRC, for predicting the remaining strength of blunt corrosion defects in moderate- to high-toughness pipe materials. The results of this investigation indicate that corrosion defects may fail by one of two potential failure mechanisms. The first is a ductile plastic collapse mechanism in which failure is controlled by the material`s ultimate tensile strength. The second is a fracture-based mechanism in which cracks may nucleate, grow, and coalesce at the base of the corrosion defect.

  17. Seepage and piping: Solitary and integrated mechanisms of streambank erosion and failure

    USDA-ARS?s Scientific Manuscript database

    Recent work has shown that a majority of the sediment entering streams and rivers now comes from streambanks. We lack the understanding of the processes controlling streambank failure to be able to predict how erosion control methods will work for all conditions. Research underway at Oklahoma State...

  18. Calculations cut drilling-rig chain-drive failure

    SciTech Connect

    Wang, H. )

    1988-10-31

    Although so-called ''fatigue resistant'' chain has been in use on drilling rigs for a long time, a rational method for the design calculation of drilling rig chain drive is still unavailable. Two general formulas are presented in this article, but more involvement of industry is needed. Horsepower rating. The horsepower rating tables currently in use, American National Standards Institute (ANSI) B29.1, were adopted in 1975 to provide a standardized basis for the selection of chain size that would give satisfactory service life. But drilling equipment manufacturers require chains capable of transmitting power at levels far exceeding the standard ratings. Many chain manufacturers have improved their fabrication and processing techniques to provide chains with much higher endurance limits to meet this requirement.

  19. Piping Analysis

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Burns & McDonnell provide architectural and engineering services in planning, design and construction of a wide range of projects all over the world. In design analysis, company regularly uses COSMIC computer programs. In computer testing piping design of a power plant, company uses Pipe Flexibility Analysis Program (MEL-21) to analyze stresses due to weight, temperature, and pressure found in proposed piping systems. Individual flow rates are put into the computer, then computer calculates the pressure drop existing across each component; if needed, design corrections or adjustments can be made and rechecked.

  20. Analysis of pressure drop characteristics and methods for calculating gas and gas-solid flow in horizontal pipes for dilute coal conveying system

    SciTech Connect

    Weiguo Pan; Zuohe Chi; Yongjing Liao

    1997-07-01

    This article reported pressure drop characteristics and methods for calculating friction factors {lambda} 0 and {lambda}{sub {mu}} for gas and gas-solids flows, respectively, in straight horizontal pipes are summarized advantages seed. The and disadvantages of calculating friction factor {lambda}{sub {mu}} through dimensional analysis in comparison with model simulation are analyzed. It is pointed out that model simulation is more suitable to engineering use than dimensional analysis. According to experimental results of dilute gas-coal powder flow in straight horizontal pipes of the coal pulverization system in a power plant; an empirical formula and a theoretical formula for calculating friction factor {lambda}{sub {mu}} in straight horizontal pipes transporting dilute coal powder are obtained.

  1. Project W-320, 241-C-106 sluicing: Piping calculations. Volume 8

    SciTech Connect

    Bailey, J.W.

    1998-07-24

    This supporting document has been prepared to make the FDNW calculations for Project W-320 readily retrievable. The objective of this calculation is to perform the hydraulic analysis on the slurry line and the supernate line for W-320. This calculation will use the As-Built conditions of the slurry line and the supernate line. Booster Pump Curves vs System Curves shall be generated for the supernate system and the slurry system.

  2. Calculations to estimate the margin to failure in the TMI-2 vessel

    SciTech Connect

    Stickler, L.A.; Rempe, J.L.; Chavez, S.A.; Thinnes, G.L.; Snow, S.D.; Witt, R.J.; Corradini, M.L.; Kos, J.A.

    1994-03-01

    As part of the OECD-sponsored Three Mile Island Unit 2 (TMI-2) Vessel Investigation Project (VIP), margin-to-failure calculations for mechanisms having the potential to threaten the integrity of the vessel were performed to improve understanding of events that occurred during the TMI-2 accident. Analyses considered four failure mechanisms: tube rupture, tube ejection, global vessel failure, and localized vessel failure. Calculational input was based on data from the TMI-2 VIP examinations of the vessel steel samples, the instrument tube nozzles, and samples of the hard layer of debris found on the TMI-2 vessel lower head. Sensitivity studies were performed to investigate the uncertainties in key parameters for these analyses.

  3. Pipe protection bibliography

    SciTech Connect

    Guy, N.G.

    1987-01-01

    Pipes and pipelines are being used for an ever widening range of materials, for increasing flows and in harsher applications. There is also more legal and social pressure to reduce the hazards associated with handling materials in pipes. All of this increases the demand for improved pipe reliability. Two of the major preventable causes of pipe failure are corrosion and wear. These may result from the pipe surroundings, or from the material which is carried and it is often impossible to prevent failure by the choice of pipe materials and design. However, additional pipe protection measures are available and it is these measures which are considered in this bibliography. The most common pipe protection methods are the application of coatings and the use of cathodic protection. Accordingly, much of this bibliography is devoted to these techniques. Articles dealing with other means of protecting pipes have also been included. The bibliography covers the protection of oil pipes, (both offshore and on land); water supply systems; gas distribution systems; sewer pipes; pipes for hydraulic and pneumatic transport of solids; power plant pipework; process plant pipework.

  4. Project W-320, 241-C-106 sluicing piping calculations, Volume 7

    SciTech Connect

    Bailey, J.W.

    1998-07-29

    The object of this report is to calculate the hydraulic forces imposed at the sluicer nozzle. This is required by Project W-320 waste retrieval for tank 241-C-106. The method of analysis used is Bernoulli`s momentum equation for stead flow.

  5. OTEC Cold Water Pipe Design for Problems Caused by Vortex-Excited Oscillations.

    DTIC Science & Technology

    to structural damage and to destructive failures. The cold water pipe of an OTEC plant is nominally a bluff, flexible cylinder with a large aspect... OTEC cold water pipe. Practical design calculations are given as examples throughout the various sections of the report. This report is limited in...structural response parameters relevant to the OTEC cold water pipe. There are important problems associated with the shedding of vortices from cylinders in

  6. Determination of the frequency of inadequate antibiotic therapy using calculation of indication failure (IF), cumulative indication failure (CIF), and balanced indication failure (BIF).

    PubMed

    Burgmann, Heinz

    2003-01-01

    Because results of pathogen identification are often lacking when antibiotic therapy is initiated, treatment must frequently be instituted on an empirical basis. The type of empirical therapy will depend on the anticipated pathogen spectrum and naturally also on the prevailing resistance patterns. Inadequate antibiotic therapy may not only be associated with increased overall treatment costs, but will also have adverse effects on mortality. The clinician is frequently faced with an overabundant variety of microbiological data and may fail to interpret them correctly. Therefore, the present study has attempted to "translate" the available microbiological resistance data, frequently presented in the form of percentage rates, into concrete patient numbers and thus illustrate the frequency of inadequate antibiotic therapy. For this purpose, "Indication Failure" (IF), "Cumulative Indication Failure" (CIF) and "Balanced Indication Failure" (BIF) have been calculated based on available microbiological data. For the indication "nosocomial pneumonia", calculations of the BIF show that only one out of 67 or one out of 63 patients is inadequately treated with a therapy with cefepime or imipenem, while one out of 25 patients is inadequately treated when using ceftazidime. However, it must be pointed out that these calculations only represent an interpretation of microbiological data and the success of antibiotic therapy will ultimately also depend on parameters such as the pharmacodynamic properties of an antibiotic or on the immunocompetence of the patient treated.

  7. Weibull Parameter Calculation and Weibull Monte Carlo Analysis for Analyzing Parts Failures in Gas Turbines and Other Equipment

    DTIC Science & Technology

    1988-07-29

    and number of failures) as well as the estimated or calculated value of time to first failure. The input screen is shown in figure 25. As in the...USED IN THIS ANALYSIS? 2000 WHAT NUMBER OF FAILURES ARE THESE VALUES OF BETA AND ETA BASED ON? 10 WHAT IS THE ESTIMATED (CALCULATED) VALUE OF TIME TO...FAILURE <= 1336.49 THE ESTIMATED VALUE OF TIME TO FIRST FAILURE IS: 1200 FIGURE 25 CNFINTBE INPUT & OUTPUT SCREENS 30 NADC-89019-60 RELIABILITY CALCULATES

  8. Heat pipe cooling system of high-power three-level explosion-proof inverter based on the loss calculation and finite element analysis

    NASA Astrophysics Data System (ADS)

    Li, Yuan

    2017-07-01

    The special using condition of high-power three-level explosion-proof inverter limits its cooling system within heat pipe and water-cooled cooling systems. How to calculate these two systems quantitatively to provide references for engineering application becomes one of the critical problems. In this paper, the principle of three-level explosion-proof was introduced first, and the power-loss generation theory was described and deduced into equations. Secondly, the heat pipe cooling system theory calculation was conducted based on the power losses of power devices, and the whole cooling system model was built by using finite element analysis. Finally, the temperature rise experiment was carried out on a 1 MW high-power three-level explosion-proof inverter, and the results proved the feasibility of this theory and its accuracy of analysis.

  9. Efficient Probability of Failure Calculations for QMU using Computational Geometry LDRD 13-0144 Final Report

    SciTech Connect

    Mitchell, Scott A.; Ebeida, Mohamed Salah; Romero, Vicente J.; Swiler, Laura Painton; Rushdi, Ahmad A.; Abdelkader, Ahmad

    2015-09-01

    This SAND report summarizes our work on the Sandia National Laboratory LDRD project titled "Efficient Probability of Failure Calculations for QMU using Computational Geometry" which was project #165617 and proposal #13-0144. This report merely summarizes our work. Those interested in the technical details are encouraged to read the full published results, and contact the report authors for the status of the software and follow-on projects.

  10. Using different calculations of pharmacy refill adherence to predict virological failure among HIV-infected patients.

    PubMed

    de Boer, I Marion; Prins, Jan M; Sprangers, Mirjam A G; Nieuwkerk, Pythia T

    2010-12-15

    Refill data are increasingly used to assess adherence in HIV-infected patients on combination antiretroviral therapy. However, it is not clear how feasible this method is when multiple pharmacies are involved. Also, the effects of inclusion of leftover medication from previous refills and prescribed treatment time on adherence calculations are unknown. We addressed these questions in the present study. Adult HIV-1-infected patients were recruited at the outpatient clinic of the Academic Medical Centre in Amsterdam and asked for their pharmacies' names. Refill data were obtained from pharmacies. Percentages of patients misclassified as nonadherent when disregarding leftover medication and prescribed treatment interruptions were calculated. Finally, we investigated whether an average adherence calculation of all drugs or a calculation based on one drug in the regimen best predicted virological failure (plasma HIV-1 RNA >40 copies/mL). Two hundred one patients were included. Collecting data from multiple pharmacies (132) was found to be feasible. Forty-three percent of patients were misclassified as nonadherent when disregarding leftover medication and 2 percent when disregarding prescribed treatment time. There was no difference in predicting virological failure by different calculations of adherence. These findings suggest that studies using pharmacy refill data should include leftover medication.

  11. Pipe-to-pipe impact program

    SciTech Connect

    Alzheimer, J.M.; Bampton, M.C.C.; Friley, J.R.; Simonen, F.A.

    1984-06-01

    This report documents the tests and analyses performed as part of the Pipe-to-Pipe Impact (PTPI) Program at the Pacific Northwest Laboratory. This work was performed to assist the NRC in making licensing decisions regarding pipe-to-pipe impact events following postulated breaks in high energy fluid system piping. The report scope encompasses work conducted from the program's start through the completion of the initial hot oil tests. The test equipment, procedures, and results are described, as are analytic studies of failure potential and data correlation. Because the PTPI Program is only partially completed, the total significance of the current test results cannot yet be accurately assessed. Therefore, although trends in the data are discussed, final conclusions and recommendations will be possible only after the completion of the program, which is scheduled to end in FY 1984.

  12. Piping inspection instrument carriage

    SciTech Connect

    Zollinger, W.T.; Treanor, R.C.

    1993-09-20

    This invention is comprised of a pipe inspection instrument carriage for use with a pipe crawler or other locomotion means for performing internal inspections of piping surfaces. The carriage has a front leg assembly, a rear leg assembly and a central support connecting the two assemblies and for mounting an instrument arm having inspection instruments. The instrument arm has means mounted distally thereon for axially aligning the inspection instrumentation and means for extending the inspection instruments radially outward to operably position the inspection instruments on the piping interior. Also, the carriage has means for rotating the central support and the front leg assembly with respect to the rear leg assembly so that the inspection instruments azimuthally scan the piping interior. The instrument carriage allows performance of all piping inspection operations with a minimum of moving parts, thus decreasing the likelihood of performance failure.

  13. Corrosion in alkali metal/molybdenum heat pipes

    SciTech Connect

    Lundberg, L.B.; Feber, R.C. Jr.

    1984-01-01

    Molybdenum/sodium (Mo/Na) and molybdenum/lithium (Mo/Li) heat pipes have been operated for long periods of time in a study of their resistance to failure by alkali metal corrosion. Some Mo/Na heat pipes have operated over 20,600 h at 1400 K without failure, while at least one similar heat pipe failed in less than 14 hours at 1435 K. Detailed post-mortem analyses which have been performed on three failed Mo/Na heat pipes all indicated impurity controlled corrosion of their evaporators. Impurities observed to be transported included carbon, oxygen, and silicon. A Mo/Li heat pipe that failed after 25,216 h of operation at 1700 K was also examined in detail. This failure was due to nickel impurities being transported to the evaporator resulting in perforation of the container tube by the formation of a low melting Mo-Ni alloy. Theoretical thermochemical calculations were conducted for these systems with the objective of corroborating the corrosion mechanisms in both types of heat pipes. The results of these calculations are in general agreement with the observed corrosion a phenomena.

  14. NASA Langley developments in response calculations needed for failure and life prediction

    NASA Technical Reports Server (NTRS)

    Housner, Jerrold M.

    1993-01-01

    NASA Langley developments in response calculations needed for failure and life predictions are discussed. Topics covered include: structural failure analysis in concurrent engineering; accuracy of independent regional modeling demonstrated on classical example; functional interface method accurately joins incompatible finite element models; interface method for insertion of local detail modeling extended to curve pressurized fuselage window panel; interface concept for joining structural regions; motivation for coupled 2D-3D analysis; compression panel with discontinuous stiffener coupled 2D-3D model and axial surface strains at the middle of the hat stiffener; use of adaptive refinement with multiple methods; adaptive mesh refinement; and studies on quantity effect of bow-type initial imperfections on reliability of stiffened panels.

  15. NASA Langley developments in response calculations needed for failure and life prediction

    NASA Astrophysics Data System (ADS)

    Housner, Jerrold M.

    1993-10-01

    NASA Langley developments in response calculations needed for failure and life predictions are discussed. Topics covered include: structural failure analysis in concurrent engineering; accuracy of independent regional modeling demonstrated on classical example; functional interface method accurately joins incompatible finite element models; interface method for insertion of local detail modeling extended to curve pressurized fuselage window panel; interface concept for joining structural regions; motivation for coupled 2D-3D analysis; compression panel with discontinuous stiffener coupled 2D-3D model and axial surface strains at the middle of the hat stiffener; use of adaptive refinement with multiple methods; adaptive mesh refinement; and studies on quantity effect of bow-type initial imperfections on reliability of stiffened panels.

  16. Helium release rates and ODH calculations from RHIC magnet cooling line failure

    SciTech Connect

    Liaw, C.J.; Than, Y.; Tuozzolo, J.

    2011-03-28

    A catastrophic failure of the magnet cooling lines, similar to the LHC superconducting bus failure incident, could discharge cold helium into the RHIC tunnel and cause an Oxygen Deficiency Hazard (ODH) problem. A SINDA/FLUINT{reg_sign} model, which simulated the 4.5K/4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the insulating vacuum volumes and discharging via the reliefs into the RHIC tunnel, had been developed. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces are included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Results, including helium discharge rates, helium inventory loss, and the resulting oxygen concentration in the RHIC tunnel area, are reported. Good agreement had been achieved when comparing the simulation results, a RHIC sector depressurization test measurement, and some simple analytical calculations.

  17. Iterative User Interface Design for Automated Sequential Organ Failure Assessment Score Calculator in Sepsis Detection.

    PubMed

    Aakre, Christopher Ansel; Kitson, Jaben E; Li, Man; Herasevich, Vitaly

    2017-05-18

    The new sepsis definition has increased the need for frequent sequential organ failure assessment (SOFA) score recalculation and the clerical burden of information retrieval makes this score ideal for automated calculation. The aim of this study was to (1) estimate the clerical workload of manual SOFA score calculation through a time-motion analysis and (2) describe a user-centered design process for an electronic medical record (EMR) integrated, automated SOFA score calculator with subsequent usability evaluation study. First, we performed a time-motion analysis by recording time-to-task-completion for the manual calculation of 35 baseline and 35 current SOFA scores by 14 internal medicine residents over a 2-month period. Next, we used an agile development process to create a user interface for a previously developed automated SOFA score calculator. The final user interface usability was evaluated by clinician end users with the Computer Systems Usability Questionnaire. The overall mean (standard deviation, SD) time-to-complete manual SOFA score calculation time was 61.6 s (33). Among the 24% (12/50) usability survey respondents, our user-centered user interface design process resulted in >75% favorability of survey items in the domains of system usability, information quality, and interface quality. Early stakeholder engagement in our agile design process resulted in a user interface for an automated SOFA score calculator that reduced clinician workload and met clinicians' needs at the point of care. Emerging interoperable platforms may facilitate dissemination of similarly useful clinical score calculators and decision support algorithms as "apps." A user-centered design process and usability evaluation should be considered during creation of these tools.

  18. Validation of Computerized Automatic Calculation of the Sequential Organ Failure Assessment Score

    PubMed Central

    Harrison, Andrew M.; Pickering, Brian W.; Herasevich, Vitaly

    2013-01-01

    Purpose. To validate the use of a computer program for the automatic calculation of the sequential organ failure assessment (SOFA) score, as compared to the gold standard of manual chart review. Materials and Methods. Adult admissions (age > 18 years) to the medical ICU with a length of stay greater than 24 hours were studied in the setting of an academic tertiary referral center. A retrospective cross-sectional analysis was performed using a derivation cohort to compare automatic calculation of the SOFA score to the gold standard of manual chart review. After critical appraisal of sources of disagreement, another analysis was performed using an independent validation cohort. Then, a prospective observational analysis was performed using an implementation of this computer program in AWARE Dashboard, which is an existing real-time patient EMR system for use in the ICU. Results. Good agreement between the manual and automatic SOFA calculations was observed for both the derivation (N=94) and validation (N=268) cohorts: 0.02 ± 2.33 and 0.29 ± 1.75 points, respectively. These results were validated in AWARE (N=60). Conclusion. This EMR-based automatic tool accurately calculates SOFA scores and can facilitate ICU decisions without the need for manual data collection. This tool can also be employed in a real-time electronic environment. PMID:23936639

  19. A Corrosion Risk Assessment Model for Underground Piping

    NASA Technical Reports Server (NTRS)

    Datta, Koushik; Fraser, Douglas R.

    2009-01-01

    The Pressure Systems Manager at NASA Ames Research Center (ARC) has embarked on a project to collect data and develop risk assessment models to support risk-informed decision making regarding future inspections of underground pipes at ARC. This paper shows progress in one area of this project - a corrosion risk assessment model for the underground high-pressure air distribution piping system at ARC. It consists of a Corrosion Model of pipe-segments, a Pipe Wrap Protection Model; and a Pipe Stress Model for a pipe segment. A Monte Carlo simulation of the combined models provides a distribution of the failure probabilities. Sensitivity study results show that the model uncertainty, or lack of knowledge, is the dominant contributor to the calculated unreliability of the underground piping system. As a result, the Pressure Systems Manager may consider investing resources specifically focused on reducing these uncertainties. Future work includes completing the data collection effort for the existing ground based pressure systems and applying the risk models to risk-based inspection strategies of the underground pipes at ARC.

  20. An analytical model for calculating pressure rise in a room due to refrigerant spills from piping rupture

    SciTech Connect

    Shin, Y.W.; Hsieh, B.J.; Kot, C.A.

    1995-04-01

    In this paper, an analytical model is presented to describe quasi- steady release of a two-phase refrigerant mixture into a room and the associated pressure transient of the room atmosphere with limited capability to discharge the atmosphere. The analytical model is based on simple, approximate thermodynamic relationships applied along isentropes, which is used to describe the release of refrigerant and the coupled set of equation of energy and mass conservation and other auxiliary equations describing pressure transient of a room atmosphere. The analytical model, which consists of a set of nonlinear ordinary differential equations, is solved numerically by the Mathematica computer program. As an example the safety problem of a Freon-22 spill in a refrigeration equipment room, resulting from piping rupture due to an earthquake, is analyzed and discussed.

  1. Probing the intrinsic failure mechanism of fluorinated amorphous carbon film based on the first-principles calculations

    PubMed Central

    Zhang, Ren-hui; Wang, Li-ping; Lu, Zhi-bin

    2015-01-01

    Fluorinated amorphous carbon films exhibit superlow friction under vacuum, but are prone to catastrophic failure. Thus far, the intrinsic failure mechanism remains unclear. A prevailing view is that the failure of amorphous carbon film results from the plastic deformation of substrates or strong adhesion between two contacted surfaces. In this paper, using first-principles and molecular dynamics methodology, combining with compressive stress-strain relation, we firstly demonstrate that the plastic deformation induces graphitization resulting in strong adhesion between two contacted surfaces under vacuum, which directly corresponds to the cause of the failure of the films. In addition, sliding contact experiments are conducted to study tribological properties of iron and fluorinated amorphous carbon surfaces under vacuum. The results show that the failure of the film is directly attributed to strong adhesion resulting from high degree of graphitization of the film, which are consistent with the calculated results. PMID:25803202

  2. Pipe support

    DOEpatents

    Pollono, Louis P.

    1979-01-01

    A pipe support for high temperature, thin-walled piping runs such as those used in nuclear systems. A section of the pipe to be supported is encircled by a tubular inner member comprised of two walls with an annular space therebetween. Compacted load-bearing thermal insulation is encapsulated within the annular space, and the inner member is clamped to the pipe by a constant clamping force split-ring clamp. The clamp may be connected to pipe hangers which provide desired support for the pipe.

  3. Heat Pipes

    ERIC Educational Resources Information Center

    Lewis, J.

    1975-01-01

    Describes the construction, function, and applications of heat pipes. Suggests using the heat pipe to teach principles related to heat transfer and gives sources for obtaining instructional kits for this purpose. (GS)

  4. Pipe Dreams.

    ERIC Educational Resources Information Center

    Milshtein, Amy

    2002-01-01

    Discusses the importance of attention to plumbing in college facilities, offering examples from various campuses. Addresses preventive maintenance, technology, and piping materials, including the debate between cast iron and PVC for drain pipes. (EV)

  5. Pipe Dreams.

    ERIC Educational Resources Information Center

    Milshtein, Amy

    2002-01-01

    Discusses the importance of attention to plumbing in college facilities, offering examples from various campuses. Addresses preventive maintenance, technology, and piping materials, including the debate between cast iron and PVC for drain pipes. (EV)

  6. Development of Probabilistic Fracture Mechanics Analysis Code for Pipes with Stress Corrosion Cracks

    NASA Astrophysics Data System (ADS)

    Machida, Hideo; Arakawa, Manabu; Yamashita, Norimichi; Yoshimura, Shinobu

    Risk-Informed integrity management methodologies have been developed for Japanese nuclear power plants. One of the issues of concern is the reliability assessment of piping with flaws due to stress corrosion cracking (SCC). Therefore, the probabilistic fracture mechanics analysis code has been developed, which can perform the reliability assessment for austenitic stainless steel piping with flaws due to SCC. This paper describes technical basis of this code. This method is based on Monte-Carlo technique considering many sample cases in a piping section, where the initiation and growth of cracks are calculated and piping failures, including leaks and rapture, are evaluated. A notable feature is that multiple cracks can be treated, consequently, assessment of coalescence of cracks and intricate break evaluation of piping section have been included. Moreover, the in-service inspection (ISI) and integrity evaluation by Fitness-for-Service (FFS) code are integrated into the analysis, and the contribution to failure probability decrease can be assessed. Key parameters are determined on a probability basis with the designated probability type throughout the procedure. Size, location and time of crack initiation, coefficients of crack growth due to SCC and factors for piping failure are included in those parameters. With this method the reliability level of the piping through the operation periods can be estimated and the contribution of various parameters including ISI can be quantitatively evaluated.

  7. An electrohydrodynamic heat pipe.

    NASA Technical Reports Server (NTRS)

    Jones, T. B.

    1972-01-01

    A heat pipe of new design, using an electrode structure to orient and guide the dielectric liquid phase flow, is proposed. Analysis indicates that the operation of the electrohydrodynamic heat pipe is in direct analogy to capillary devices, with the polarization force acting in place of capillarity. Advantages of these new heat pipes include greatly reduced liquid friction, electrohydrodynamically enhanced evaporation and condensation heat transfer, and a possible voltage-controlled on/off feature. Preliminary calculations indicate that relatively high performance devices are possible.

  8. An electrohydrodynamic heat pipe.

    NASA Technical Reports Server (NTRS)

    Jones, T. B.

    1972-01-01

    A heat pipe of new design, using an electrode structure to orient and guide the dielectric liquid phase flow, is proposed. Analysis indicates that the operation of the electrohydrodynamic heat pipe is in direct analogy to capillary devices, with the polarization force acting in place of capillarity. Advantages of these new heat pipes include greatly reduced liquid friction, electrohydrodynamically enhanced evaporation and condensation heat transfer, and a possible voltage-controlled on/off feature. Preliminary calculations indicate that relatively high performance devices are possible.

  9. Calculation of the pressure vessel failure fraction of fuel particle of gas turbine high temperature reactor 300 C

    SciTech Connect

    Aihara, J.; Ueta, S.; Mozumi, Y.; Sato, H.; Sawa, K.; Motohashi, Y.

    2007-07-01

    In high temperature gas-cooled reactors (HTGRs), coated particles are used as fuels. For upgrading HTGR technologies, present SiC coating layer which is used as the 3. layer could be replaced with ZrC coating layer which have much higher temperature stability in addition to higher resistance to chemical attack by fission product palladium than the SiC coating layer. The ZrC layer could deform plastically at high temperatures. Therefore, the Japan Atomic Energy Agency modified an existing pressure vessel failure fraction calculation code to treat the plastic deformation of the 3. layer in order to predict failure fraction of ZrC coated particle under irradiation. Finite element method is employed to calculate the stress in each coating layer. The pressure vessel failure fraction of the coated fuel particles under normal operating condition of GTHTR300C is calculated by the modified code. The failure fraction is evaluated as low as 3.5 x 10{sup -6}. (authors)

  10. Heat Pipes

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Phoenix Refrigeration Systems, Inc.'s heat pipe addition to the Phoenix 2000, a supermarket rooftop refrigeration/air conditioning system, resulted from the company's participation in a field test of heat pipes. Originally developed by NASA to control temperatures in space electronic systems, the heat pipe is a simple, effective, heat transfer system. It has been used successfully in candy storage facilities where it has provided significant energy savings. Additional data is expected to fully quantify the impact of the heat pipes on supermarket air conditioning systems.

  11. Pipe connector

    DOEpatents

    Sullivan, Thomas E.; Pardini, John A.

    1978-01-01

    A safety test facility for testing sodium-cooled nuclear reactor components includes a reactor vessel and a heat exchanger submerged in sodium in the tank. The reactor vessel and heat exchanger are connected by an expansion/deflection pipe coupling comprising a pair of coaxially and slidably engaged tubular elements having radially enlarged opposed end portions of which at least a part is of spherical contour adapted to engage conical sockets in the ends of pipes leading out of the reactor vessel and in to the heat exchanger. A spring surrounding the pipe coupling urges the end portions apart and into engagement with the spherical sockets. Since the pipe coupling is submerged in liquid a limited amount of leakage of sodium from the pipe can be tolerated.

  12. Repair of filament wound composite pipes

    NASA Astrophysics Data System (ADS)

    Amali, Ramin; Arnall, Heather

    2015-07-01

    Filament wound pipes are used in a wide variety of industries, due to the advantages composites have over metal pipes, such as a high strength to weight ratio, and resistance against frost, corrosion and heat. Composite pipes require minimal maintenance to ensure they are safe. Any damage occurring in composite pipes could lead to failure; therefore all damage should be assessed through NDT. If it is decided that the damage makes the pipe unsafe then a decision needs to be made whether to repair or replace the pipe. Repairing a composite pipe can be quicker, easier and cheaper than replacing it and can restore the strength of the pipe effectively. This investigation looks at the repair process and the parameters involved in determining the strength of the pipe following repair through the use of over 150 models in FEA software, Abaqus. Parameters considered include the pipe diameter and thickness, damage removal size and wrap width and thickness. It was found that if the pipe is thin-walled then it can be assumed that the pipe's thickness has no effect on the FOS following repair. Formulas were created to predict the FOS following repair for varying pipe diameters, damage sizes and wrap thickness. Formulas were also created to determine the wrap width required for varying wrap thicknesses and damage sizes.

  13. Abrasion protection in process piping

    SciTech Connect

    Accetta, J.

    1996-07-01

    Process piping often is subjected to failure from abrasion or a combination of abrasion and corrosion. Abrasion is a complex phenomenon, with many factors involved to varying degrees. Hard, mineral based alumina ceramic and basalt materials are used to provide protection against abrasion in many piping systems. Successful life extension examples are presented from many different industries. Lined piping components require special attention with regard to operating conditions as well as design and engineering considerations. Economic justification involves direct cost comparisons and avoided costs.

  14. Why use preinsulated pipes for district cooling?

    SciTech Connect

    Palle, S.

    1996-11-01

    The article describes the properties of preinsulated pipes and compares them with other types of pipes. Transmission coefficients for the preinsulated pipes and a table for the hydraulic capacity are indicated. These values form some of the basis of the economic analyses which are necessary for the choice of pipes for cooling projects. In addition, the article describes the diffusion mechanism and indicates material parameters for the calculation of water vapour and oxygen diffusion or permeability. Examples are calculated which show that the permeability of vapour and oxygen does not cause any limitations of use of standard preinsulated pipes for normal district cooling projects.

  15. Piping Flexibility

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A NASA computer program aids Hudson Engineering Corporation, Houston, Texas, in the design and construction of huge petrochemical processing plants like the one shown, which is located at Ju'aymah, Saudi Arabia. The pipes handling the flow of chemicals are subject to a variety of stresses, such as weight and variations in pressure and temperature. Hudson Engineering uses a COSMIC piping flexibility analysis computer program to analyze stresses and unsure the necessary strength and flexibility of the pipes. This program helps the company realize substantial savings in reduced engineering time.

  16. Crack shape developments and leak rates for circumferential complex-cracked pipes

    SciTech Connect

    Brickstad, B.; Bergman, M.

    1997-04-01

    A computerized procedure has been developed that predicts the growth of an initial circumferential surface crack through a pipe and further on to failure. The crack growth mechanism can either be fatigue or stress corrosion. Consideration is taken to complex crack shapes and for the through-wall cracks, crack opening areas and leak rates are also calculated. The procedure is based on a large number of three-dimensional finite element calculations of cracked pipes. The results from these calculations are stored in a database from which the PC-program, denoted LBBPIPE, reads all necessary information. In this paper, a sensitivity analysis is presented for cracked pipes subjected to both stress corrosion and vibration fatigue.

  17. Wall thinning criteria for low temperature-low pressure piping

    SciTech Connect

    Mertz, G.E.

    1993-01-01

    This acceptance criteria is intended to prevent gross rupture or rapidly propagating failure during normal and abnormal operating conditions. Pitting may be present in the carbon steel piping. While the acceptance criteria have provisions to preclude gross rupture through a pitted region, they do not protect against throughwall pit growth and subsequent leakage. Potential leakage through a pit in low pressure piping is less than the post-DBE design basis leakage. Both the uniform thinning and LTA criteria protect against leakage, since their potential for leakage is larger. The acceptance criteria protects against gross rupture due to general wall thinning, local wall thinning (LTA's), pitting, and fracture through weld defects. General wall thinning calculations are based on the restart criteria, SEP-24. LTA criteria for hoop stresses are based on ASME Code Case N-480 [open quotes]Examination Requirements for Pipe Wall Thinning Due to Single Phase Erosion and Corrosion[close quotes]. The LTA criteria for axial stress is based on an effective average thickness concept, which prevents plastic collapse of a locally thinned pipe. Limits on pit density, based on an effective cross section concept, are used to prevent gross rupture through a group of pits. The CEGB R-6 failure assessment diagram is used in the fracture evaluation, along with postulated weld defects. This criteria is intended for low temperature, low pressure piping systems. Corrosion and/or weld defects increase the peak stresses during normal operation and may lead to a reduction in fatigue life. Piping systems subject to significant thermal or mechanical fatigue will require additional analysis which is beyond the scope of this document.

  18. Pipe performance analysis with nonparametric regression

    NASA Astrophysics Data System (ADS)

    Liu, Zheng; Hu, Yafei; Wu, Wei

    2011-04-01

    Asbestos cement (AC) water mains were installed extensively in North America, Europe, and Australia during 1920s-1980s and subject to a high breakage rate in recent years in some utilities. It is essential to understand how the influential factors contribute to the degradation and failure of AC pipes. The historical failure data collected from twenty utilities are used in this study to explore the correlation between pipe condition and its working environment. In this paper, we applied four nonparametric regression methods to model the relationship between pipe failure represented by average break rates and influential variables including pipe age and internal and external working environmental parameters. The nonparametric regression models do not take a predetermined form but it needs information derived from data. The feasibility of using a nonparametric regression model for the condition assessment of AC pipes is investigated and understood.

  19. The effect of time delays in fuel pin failure on LOF-TOP transient calculations for a commercial-sized LMFBR

    SciTech Connect

    Pizzica, P.A.; Hummel, H.H.

    1982-02-01

    Various loss-of-flow cases have been calculated for a commercial-sized liquid-metal fast breeder reactor. Particular attention has been paid to the development of loss-of-flow-driven transient-overpower (LOF-TOP) conditions. In such conditions, it is crucial to consider when an initial cladding breach might occur in LOF-TOP pins and over what length of time the initial cladding breach might extend in fuel pins failing under burst pressure. This study shows that the neutronic energy deposition in transient calculations including LOF-TOP pin failures can increase substantially compared to a calculation excluding such LOF-TOP failures in two ways. First, there will be an increase if there is no extension of an initial cladding failure in LOF-TOP pins or if there is a relatively long delay in the extension. Secondly, when, in applying a fuel melt fraction criterion for pin failure, the same melt fraction is specified for failure extension as for initial failure, which implies a certain delay time for failure extension, there will be an increase in the energy deposition compared to the case without any LOF-TOP failures only when the specified fuel melt fraction becomes very large. However, even in the case with the largest failure melt fraction, there will be no increase in energy deposition when a rapid enough failure extension is assumed. These calculations make a number of very conservative assumptions. The purpose of the study is not to provide a best estimate of accident conditions but to show how quickly an initial cladding breach must extend in such conservative calculations if it is to limit the increase in neutronic energy deposition.

  20. Acme jumper pipe

    SciTech Connect

    Medved, P.; Thomas, H.

    1995-09-01

    Acme Steel had operated the larry car with an attached jumper pipe since 1977. Acme had been able to meet the State Implementation Plan. With the advent of the Clean Air Act, Acme did not feel it could meet these new standards without some modifications to the jumper pipe system. Several drop sleeve modifications and numerous boot seal materials and configurations were tested that resulted in limited success in improving the boot seal life. After these modifications, Acme`s testing revealed it could meet the Clean Air Act standards, but it would be cost prohibitive to continue to operate in this manner. Following extensive investigation, Acme decided to install an off-car jumper pipe system which uses a traveling U-tube for connecting to the assist oven through an additional hole in each oven roof. Temperature related failures of drop sleeve seals were eliminated. The off-car jumper pipe is a more efficient gas connection to the assist oven and enables Acme to meet the Clean Air Act charging requirements in a cost effective manner.

  1. Solving FRP piping and ducting problems

    SciTech Connect

    Britt, F.

    1997-12-01

    This paper presents an analytical approach to the design and installation of FRP piping and duct systems that can be used by piping designers and engineers to prevent failures. Design, installation, testing, and start up procedures will be presented that have proven to provide safe and long lasting service. Procedures offered will insure the most cost effective system based on operational requirements.

  2. Heat Pipes

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Bobs Candies, Inc. produces some 24 million pounds of candy a year, much of it 'Christmas candy.' To meet Christmas demand, it must produce year-round. Thousands of cases of candy must be stored a good part of the year in two huge warehouses. The candy is very sensitive to temperature. The warehouses must be maintained at temperatures of 78-80 degrees Fahrenheit with relative humidities of 38- 42 percent. Such precise climate control of enormous buildings can be very expensive. In 1985, energy costs for the single warehouse ran to more than $57,000 for the year. NASA and the Florida Solar Energy Center (FSEC) were adapting heat pipe technology to control humidity in building environments. The heat pipes handle the jobs of precooling and reheating without using energy. The company contacted a FSEC systems engineer and from that contact eventually emerged a cooperative test project to install a heat pipe system at Bobs' warehouses, operate it for a period of time to determine accurately the cost benefits, and gather data applicable to development of future heat pipe systems. Installation was completed in mid-1987 and data collection is still in progress. In 1989, total energy cost for two warehouses, with the heat pipes complementing the air conditioning system was $28,706, and that figures out to a cost reduction.

  3. Heat Pipes

    NASA Astrophysics Data System (ADS)

    1990-01-01

    Bobs Candies, Inc. produces some 24 million pounds of candy a year, much of it 'Christmas candy.' To meet Christmas demand, it must produce year-round. Thousands of cases of candy must be stored a good part of the year in two huge warehouses. The candy is very sensitive to temperature. The warehouses must be maintained at temperatures of 78-80 degrees Fahrenheit with relative humidities of 38- 42 percent. Such precise climate control of enormous buildings can be very expensive. In 1985, energy costs for the single warehouse ran to more than 57,000 for the year. NASA and the Florida Solar Energy Center (FSEC) were adapting heat pipe technology to control humidity in building environments. The heat pipes handle the jobs of precooling and reheating without using energy. The company contacted a FSEC systems engineer and from that contact eventually emerged a cooperative test project to install a heat pipe system at Bobs' warehouses, operate it for a period of time to determine accurately the cost benefits, and gather data applicable to development of future heat pipe systems. Installation was completed in mid-1987 and data collection is still in progress. In 1989, total energy cost for two warehouses, with the heat pipes complementing the air conditioning system was 28,706, and that figures out to a cost reduction.

  4. Physics of heat pipe rewetting

    NASA Technical Reports Server (NTRS)

    Chan, S. H.

    1994-01-01

    This is the final report which summarizes the research accomplishments under the project entitled 'Physics of Heat Pipe Rewetting' under NASA Grant No. NAG 9-525, Basic, during the period of April 1, 1991 to January 31, 1994. The objective of the research project was to investigate both analytically and experimentally the rewetting characteristics of the heated, grooved plate. The grooved plate is to simulate the inner surface of the vapor channel in monogroove heat pipes for space station design. In such designs, the inner surface of the vapor channel is threaded with monogrooves. When the heat pipe is thermally overloaded, dryout of the monogroove surface occurs. Such a dryout surface should be promptly rewetted to prevent the failure of the heat pipe operation in the thermal radiator of the space station.

  5. 14 CFR 25.1123 - Exhaust piping.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Exhaust System § 25.1123 Exhaust piping. For powerplant... corrosion resistant, and must have provisions to prevent failure due to expansion by operating...

  6. 14 CFR 25.1123 - Exhaust piping.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Exhaust System § 25.1123 Exhaust piping. For powerplant... corrosion resistant, and must have provisions to prevent failure due to expansion by operating...

  7. 14 CFR 25.1123 - Exhaust piping.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Exhaust System § 25.1123 Exhaust piping. For powerplant... corrosion resistant, and must have provisions to prevent failure due to expansion by operating...

  8. 14 CFR 25.1123 - Exhaust piping.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Exhaust System § 25.1123 Exhaust piping. For powerplant... corrosion resistant, and must have provisions to prevent failure due to expansion by operating...

  9. 14 CFR 25.1123 - Exhaust piping.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Exhaust System § 25.1123 Exhaust piping. For powerplant... corrosion resistant, and must have provisions to prevent failure due to expansion by operating...

  10. Piping Connector

    NASA Technical Reports Server (NTRS)

    1993-01-01

    A complex of high pressure piping at Stennis Space Center carries rocket propellants and other fluids/gases through the Center's Component Test Facility. Conventional clamped connectors tend to leak when propellant lines are chilled to extremely low temperatures. Reflange, Inc. customized an existing piping connector to include a secondary seal more tolerant of severe thermal gradients for Stennis. The T-Con connector solved the problem, and the company is now marketing a commercial version that permits testing, monitoring or collecting any emissions that may escape the primary seal during severe thermal transition.

  11. Pipe gripper

    DOEpatents

    Moyers, S.M.

    1975-12-16

    A device for gripping the exterior surface of a pipe or rod is described which has a plurality of wedges, each having a concave face which engages the outer surface of the pipe and each having a smooth face opposing the concave face. The wedges are seated on and their grooved concave faces are maintained in circular alignment by tapered axial segments of an opening extending through a wedge-seating member. The wedges are allowed to slide across the tapered axial segments so that such a sliding movement acts to vary the diameter of the circular alignment.

  12. Heat Pipes

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Heat Pipes were originally developed by NASA and the Los Alamos Scientific Laboratory during the 1960s to dissipate excessive heat build- up in critical areas of spacecraft and maintain even temperatures of satellites. Heat pipes are tubular devices where a working fluid alternately evaporates and condenses, transferring heat from one region of the tube to another. KONA Corporation refined and applied the same technology to solve complex heating requirements of hot runner systems in injection molds. KONA Hot Runner Systems are used throughout the plastics industry for products ranging in size from tiny medical devices to large single cavity automobile bumpers and instrument panels.

  13. Piping inspection carriage having axially displaceable sensor

    DOEpatents

    Zollinger, W.T.; Treanor, R.C.

    1994-12-06

    A pipe inspection instrument carriage is described for use with a pipe crawler for performing internal inspections of piping surfaces. The carriage has a front leg assembly, a rear leg assembly and a central support connecting the two assemblies and for mounting an instrument arm having inspection instruments. The instrument arm has a Y-arm mounted distally thereon for axially aligning the inspection instrumentation and a mounting block, a linear actuator and axial movement arm for extending the inspection instruments radially outward to operably position the inspection instruments on the piping interior. Also, the carriage has a rotation motor and gear assembly for rotating the central support and the front leg assembly with respect to the rear leg assembly so that the inspection instruments azimuthally scan the piping interior. The instrument carriage allows performance of all piping inspection operations with a minimum of moving parts, thus decreasing the likelihood of performance failure. 4 figures.

  14. Piping inspection carriage having axially displaceable sensor

    DOEpatents

    Zollinger, William T.; Treanor, Richard C.

    1994-01-01

    A pipe inspection instrument carriage for use with a pipe crawler for performing internal inspections of piping surfaces. The carriage has a front leg assembly, a rear leg assembly and a central support connecting the two assemblies and for mounting an instrument arm having inspection instruments. The instrument arm has a y-arm mounted distally thereon for axially aligning the inspection instrumentation and a mounting block, a linear actuator and axial movement arm for extending the inspection instruments radially outward to operably position the inspection instruments on the piping interior. Also, the carriage has a rotation motor and gear assembly for rotating the central support and the front leg assembly with respect to the rear leg assembly so that the inspection instruments azimuthally scan the piping interior. The instrument carriage allows performance of all piping inspection operations with a minimum of moving parts, thus decreasing the likelihood of performance failure.

  15. Extended Development of Variable Conductance Heat Pipes

    NASA Technical Reports Server (NTRS)

    Antoniuk, D.; Edwards, D. K.; Luedke, E. E.

    1978-01-01

    A high-capacity vapor-modulated heat pipe was designed and tested. In 1977, a program was undertaken to use the aforementioned heat pipe to study protection from freezing-point failure, increase control sensitivity, and transient behavior under a wide range of operating conditions in order to determine the full performance potential of the heat pipe. A new concept, based on the vapor-induced-dry-out principle, was developed for passive feedback temperature control as a heat pipe diode. This report documents this work and describes: (1) the experimental and theoretical investigation of the performance of the vapor-modulated heat pipe; and (2) the design, fabrication and test of the heat pipe diode.

  16. Explosive Welding of Pipes

    NASA Astrophysics Data System (ADS)

    Drennov, Oleg; Drennov, Andrey; Burtseva, Olga

    2013-06-01

    For connection by welding it is suggested to use the explosive welding method. This method is rather new. Nevertheless, it has become commonly used among the technological developments. This method can be advantageous (saving material and physical resources) comparing to its statical analogs (electron-beam welding, argon-arc welding, plasma welding, gas welding, etc.), in particular, in hard-to-reach areas due to their geographic and climatic conditions. Explosive welding of cylindrical surfaces is performed by launching of welded layer along longitudinal axis of construction. During this procedure, it is required to provide reliable resistance against radial convergent strains. The traditional method is application of fillers of pipe cavity, which are dense cylindrical objects having special designs. However, when connecting pipes consecutively in pipelines by explosive welding, removal of the fillers becomes difficult and sometimes impossible. The suggestion is to use water as filler. The principle of non-compressibility of liquid under quasi-dynamic loading is used. In one-dimensional gasdynamic and elastic-plastic calculations we determined non-deformed mass of water (perturbations, which are moving in the axial direction with sound velocity, should not reach the layer end boundaries for 5-7 circulations of shock waves in the radial direction). Linear dimension of the water layer from the zone of pipe coupling along axis in each direction is >= 2R, where R is the internal radius of pipe.

  17. Evaluations of Structural Failure Probabilities and Candidate Inservice Inspection Programs

    SciTech Connect

    Khaleel, Mohammad A.; Simonen, Fredric A.

    2009-05-01

    The work described in this report applies probabilistic structural mechanics models to predict the reliability of nuclear pressure boundary components. These same models are then applied to evaluate the effectiveness of alternative programs for inservice inspection to reduce these failure probabilities. Results of the calculations support the development and implementation of risk-informed inservice inspection of piping and vessels. Studies have specifically addressed the potential benefits of ultrasonic inspections to reduce failure probabilities associated with fatigue crack growth and stress-corrosion cracking. Parametric calculations were performed with the computer code pc-PRAISE to generate an extensive set of plots to cover a wide range of pipe wall thicknesses, cyclic operating stresses, and inspection strategies. The studies have also addressed critical inputs to fracture mechanics calculations such as the parameters that characterize the number and sizes of fabrication flaws in piping welds. Other calculations quantify uncertainties associated with the inputs calculations, the uncertainties in the fracture mechanics models, and the uncertainties in the resulting calculated failure probabilities. A final set of calculations address the effects of flaw sizing errors on the effectiveness of inservice inspection programs.

  18. EVALUATION OF THE FAILURE OF A RADIOACTIVE WASTE TRANSFER LINE JACKET

    SciTech Connect

    Wiersma, B; Alan03 Plummer, A; Karthik Subramanian, K; Charles Jenkins, C; William Hinz, W; A Fellinger, A

    2007-04-06

    Radioactive wastes are confined in 49 underground storage tanks at the Savannah River Site. The waste is transported between tanks primarily via an underground transfer piping system. Due to the hazardous nature of the waste, the inner core stainless steel pipe is typically surrounded by a carbon steel pipe jacket, which provides secondary containment. Recently several through-wall penetrations were discovered on a segment of one of the jackets. An evaluation was performed to verify the failure mechanism and to estimate the degree of damage that occurred to the pipe segment. Failure analysis of a section of the jacket confirmed that pitting corrosion on the exterior of the pipe led to the through-wall penetration. Ultrasonic measurements on sections of the pipe were utilized to determine the remaining wall thickness in adjacent areas of the pipe. Based on these measurements, the degree of pitting and general corrosion was determined. Pit growth rate models were then developed to estimate the life expectancy of sections of the pipe that had not been excavated. The calculations estimated that the occurrence of through-wall failures in this jacket will begin to increase substantially in 12 years. Given that this pipe segment will be utilized beyond this time, short-term and long-term solutions to this failure were proposed. The short-term solutions focused on the repair or replace decisions that must be made to return the jacket to service as soon as practical. The long-term solutions focused on a broader strategy to address jacket integrity issues in the entire tank farm facility. These solutions included the evaluation of innovative remote inspection and repair techniques.

  19. Thermal-structural analysis of the platelet heat-pipe-cooled leading edge of hypersonic vehicle

    NASA Astrophysics Data System (ADS)

    Hongpeng, Liu; Weiqiang, Liu

    2016-10-01

    One of the main challenges for the hypersonic vehicle is its thermal protection, more specifically, the cooling of its leading edge. To investigate the feasibility of a platelet heat-pipe-cooled leading edge structure, thermal/stress distributions for steady-state flight conditions are calculated numerically. Studies are carried on for IN718/Na, C-103/Na and T-111/Li compatible material combinations of heat pipe under nominal operations and a central heat pipe failure cases, and the influence of wall thickness on the design robustness is also investigated. And the heat transfer limits (the sonic limit, the capillary limit and the boiling limit) are also computed to check the operation of platelet heat pipes. The results indicate that, with a 15 mm leading edge radius and a wall thickness of 0.5 mm, C-103/Na and T-111/Li combinations of heat pipe is capable of withstanding both nominal and failure conditions for Mach 8 and Mach 10 flight respectively.

  20. Analysis of piping response to thermal and operational transients

    SciTech Connect

    Wang, C.Y.

    1987-01-01

    The reactor piping system is an extremely complex three-dimensional structure. Maintaining its structural integrity is essential to the safe operation of the reactor and the steam-supply system. In the safety analysis, various transient loads can be imposed on the piping which may cause plastic deformation and possible damage to the system, including those generated from hydrodynamic wave propagations, thermal and operational transients, as well as the seismic events. At Argonne National Laboratory (ANL), a three-dimensional (3-D) piping code, SHAPS, aimed for short-duration transients due to wave propagation, has been developed. Since 1984, the development work has been shifted to the long-duration accidents originating from the thermal and operational transient. As a result, a new version of the code, SHAPS-2, is being established. This paper describes many features related to this later development. To analyze piping response generated from thermal and operational transients, a 3-D implicit finite element algorithm has been developed for calculating the hoop, flexural, axial, and torsional deformations induced by the thermomechanical loads. The analysis appropriately accounts for stresses arising from the temperature dependence of the elastic material properties, the thermal expansion of the materials, and the changes in the temperature-dependent yield surface. Thermal softening, failure, strain rate, creep, and stress ratching can also be considered.

  1. Analysis of Deformation Behavior of Plastic during Lining on Steel Pipe with an FEM

    NASA Astrophysics Data System (ADS)

    Yamada, Toshiro; Mikawa, Toshihide; Kushizaki, Yoshiyuki

    2007-05-01

    There exist serious issues on the poor adhesion and residual stress of plastics on the steel pipe lined with plastics such as polyvinyl chloride (PVC), polyethylene (PE) and polypropylene (PP), which cause the interface delamination and crack of plastics. In order to prevent the failure during lining, the optimum lining conditions such as temperature pattern and the length of plastic pipe are not determined by the theoretical analysis but by trial and error because of the following reasons: As a plastic pipe is longitudinally stretched in advance, it has the strong anisotropy that it shrinks in the longitudinal direction and expands in the circumferential direction while sliding and adhesion of plastics at the contact point with steel during lining. Moreover, plastics are usually a viscoelastic material; the dynamic behavior is remarkably dependent on temperature and time. In this work, the authors have tried to analyze the deformation behavior of polyvinyl chloride (PVC) lining a steel pipe during lining. Mechanical and viscoelastic properties of stretched PVC pipe have been measured in the longitudinal and circumferential directions. The deformation behavior of PVC pipe has been numerically predicted by a finite element analysis (FEA) under the assumption of anisotropic and viscoelastic material during lining. It has been confirmed that the calculated results by an FEA can give the good agreement with experimental ones.

  2. Heat pipe technology

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A bibliography of heat pipe technology to provide a summary of research projects conducted on heat pipes is presented. The subjects duscussed are: (1) heat pipe applications, (2) heat pipe theory, (3) design and fabrication, (4) testing and operation, (5) subject and author index, and (6) heat pipe related patents.

  3. System for Testing Thermal Insulation of Pipes

    NASA Technical Reports Server (NTRS)

    Fesmire, James E.; Augustynowicz, Stanislaw D.; Nagy, Zoltan F.

    2003-01-01

    An apparatus and method have been developed for measuring the rates of leakage of heat into pipes carrying liquids, the purpose of the measurements being to quantify the thermal performance of the insulation system. The apparatus is designed primarily for testing pipes used to carry cryogenic liquids, but can also be used for measuring the thermal performance of other insulated pipes or piping systems. The basic measurement principle is straightforward: The outer surface of the pipe insulation is maintained at a fixed warmer temperature. The interior of the pipe is maintained in a narrow fixed lower-temperature range by means of a regular liquid (e.g., water) that is pumped through the pipe at a known flow rate or a cryogenic liquid (e.g., nitrogen) that is saturated at atmospheric pressure and replenished until steady-state conditions are achieved. In the case of water or another liquid pumped through, the inlet and outlet temperatures are measured and heat-leak power is calculated as the mass flow rate of the liquid multiplied by the specific heat of the liquid multiplied by the inlet-to-outlet temperature rise of the liquid. In the case of liquid nitrogen or another low-temperature boiling liquid, the heat-leak power is calculated as the rate of boil-off multiplied by the latent heat of vaporization of the liquid. Then the thermal-insulation performance of the pipe system can be calculated as a function of the measured heat-leak power, the inner and outer boundary temperatures, and the dimensions of the pipe. The apparatus can test as many as three pipes simultaneously. The pipes can have inner diameters up to .15 cm and outer diameters up to .20 cm. The lengths of the pipes may vary; typical lengths are of the order of 18 m. Two thermal guard boxes . one for each end of the pipe(s) under test . are used to make the inlet and outlet fluid connections to the pipe(s) (see figure). The connections include bellows that accommodate thermal expansion and contraction

  4. Risk assessment model to prioritize sewer pipes inspection in wastewater collection networks.

    PubMed

    Anbari, Mohammad Javad; Tabesh, Massoud; Roozbahani, Abbas

    2017-04-01

    In wastewater systems as one of the most important urban infrastructures, the adverse consequences and effects of unsuitable performance and failure event can sometimes lead to disrupt part of a city functioning. By identifying high failure risk areas, inspections can be implemented based on the system status and thus can significantly increase the sewer network performance. In this study, a new risk assessment model is developed to prioritize sewer pipes inspection using Bayesian Networks (BNs) as a probabilistic approach for computing probability of failure and weighted average method to calculate the consequences of failure values. Finally to consider uncertainties, risk of a sewer pipe is obtained from integration of probability and consequences of failure values using a fuzzy inference system (FIS). As a case study, sewer pipes of a local wastewater collection network in Iran are prioritized to inspect based on their criticality. Results show that majority of sewers (about 62%) has moderate risk, but 12%of sewers are in a critical situation. Regarding the budgetary constraints, the proposed model and resultant risk values are expected to assist wastewater agencies to repair or replace risky sewer pipelines especially in dealing with incomplete and uncertain datasets.

  5. Acceleration of MCNP calculations for small pipes configurations by using Weigth Windows Importance cards created by the SN-3D ATTILA

    NASA Astrophysics Data System (ADS)

    Castanier, Eric; Paterne, Loic; Louis, Céline

    2017-09-01

    In the nuclear engineering, you have to manage time and precision. Especially in shielding design, you have to be more accurate and efficient to reduce cost (shielding thickness optimization), and for this, you use 3D codes. In this paper, we want to see if we can easily applicate the CADIS methods for design shielding of small pipes which go through large concrete walls. We assess the impact of the WW generated by the 3D-deterministic code ATTILA versus WW directly generated by MCNP (iterative and manual process). The comparison is based on the quality of the convergence (estimated relative error (σ), Variance of Variance (VOV) and Figure of Merit (FOM)), on time (computer time + modelling) and on the implement for the engineer.

  6. Sink or swim pipe

    SciTech Connect

    Dubois, B.C.; Rhines, J.A.

    1985-07-01

    The development of a six-inch ID flexible pipe system for use as a rapidly deployable offshore fuel delivery system is described. Pipe design data, pipe construction, and advantages of the offshore petroleum delivery system are discussed.

  7. Characterization of a carbon fiber reinforced polymer repair system for structurally deficient steel piping

    NASA Astrophysics Data System (ADS)

    Wilson, Jeffrey M.

    This Dissertation investigates a carbon fiber reinforced polymer repair system for structurally deficient steel piping. Numerous techniques exist for the repair of high-pressure steel piping. One repair technology that is widely gaining acceptance is composite over-wraps. Thermal analytical evaluations of the epoxy matrix material produced glass transition temperature results, a cure kinetic model, and a workability chart. These results indicate a maximum glass transition temperature of 80°C (176°F) when cured in ambient conditions. Post-curing the epoxy, however, resulted in higher glass-transition temperatures. The accuracy of cure kinetic model presented is temperature dependent; its accuracy improves with increased cure temperatures. Cathodic disbondment evaluations of the composite over-wrap show the epoxy does not breakdown when subjected to a constant voltage of -1.5V and the epoxy does not allow corrosion to form under the wrap from permeation. Combustion analysis of the composite over-wrap system revealed the epoxy is flammable when in direct contact with fire. To prevent combustion, an intumescent coating was developed to be applied on the composite over-wrap. Results indicate that damaged pipes repaired with the carbon fiber composite over-wrap withstand substantially higher static pressures and exhibit better fatigue characteristics than pipes lacking repair. For loss up to 80 percent of the original pipe wall thickness, the composite over-wrap achieved failure pressures above the pipe's specified minimum yield stress during monotonic evaluations and reached the pipe's practical fatigue limit during cyclical pressure testing. Numerous repairs were made to circular, thru-wall defects and monotonic pressure tests revealed containment up to the pipe's specified minimum yield strength for small diameter defects. The energy release rate of the composite over-wrap/steel interface was obtained from these full-scale, leaking pipe evaluations and results

  8. Stability of cracked pipe under inertial stresses. Subtask 1.1 final report

    SciTech Connect

    Scott, P.; Wilson, M.; Olson, R.; Marschall, C.; Schmidt, R.; Wilkowski, G.

    1994-08-01

    This report presents the results of the pipe fracture experiments, analyses, and material characterization efforts performed within Subtask 1.1 of the IPIRG Program. The objective of Subtask 1.1 was to experimentally verify the analysis methodologies for circumferentially cracked pipe subjected primarily to inertial stresses. Eight cracked-pipe experiments were conducted on 6-inch nominal diameter TP304 and A106B pipe. The experimental procedure was developed using nonlinear time-history finite element analyses which included the nonlinear behavior due to the crack. The model did an excellent job of predicting the displacements, forces, and times to maximum moment. The comparison of the experimental loads to the predicted loads by the Net-Section-Collapse (NSC), Dimensionless Plastic-Zone Parameter, J-estimation schemes, R6, and ASME Section XI in-service flaw assessment criteria tended to underpredict the measured bending moments except for the NSC analysis of the A106B pipe. The effects of flaw geometry and loading history on toughness were evaluated by calculating the toughness from the pipe tests and comparing these results to C(l) values. These effects were found to be variable. The surface-crack geometry tended to increase the toughness (relative to CM results), whereas a negative load-ratio significantly decreased the TP304 stainless steel surface-cracked pipe apparent toughness. The inertial experiments tended to achieve complete failure within a few cycles after reaching maximum load in these relatively small diameter pipe experiments. Hence, a load-controlled fracture mechanics analysis may be more appropriate than a displacement-controlled analysis for these tests.

  9. Detection of Fatigue Crack in Basalt FRP Laminate Composite Pipe using Electrical Potential Change Method

    NASA Astrophysics Data System (ADS)

    Altabey, Wael A.; Noori, Mohammed

    2017-05-01

    Novel modulation electrical potential change (EPC) method for fatigue crack detection in a basalt fibre reinforced polymer (FRP) laminate composite pipe is carried out in this paper. The technique is applied to a laminate pipe with an embedded crack in three layers [0º/90º/0º]s. EPC is applied for evaluating the dielectric properties of basalt FRP pipe by using an electrical capacitance sensor (ECS) to discern damages in the pipe. Twelve electrodes are mounted on the outer surface of the pipe and the changes in the modulation dielectric properties of the piping system are analyzed to detect damages in the pipe. An embedded crack is created by a fatigue internal pressure test. The capacitance values, capacitance change and node potential distribution of ECS electrodes are calculated before and after crack initiates using a finite element method (FEM) by ANSYS and MATLAB, which are combined to simulate sensor characteristics and fatigue behaviour. The crack lengths of the basalt FRP are investigated for various number of cycles to failure for determining crack growth rate. Response surfaces are adopted as a tool for solving inverse problems to estimate crack lengths from the measured electric potential differences of all segments between electrodes to validate the FEM results. The results show that, the good convergence between the FEM and estimated results. Also the results of this study show that the electrical potential difference of the basalt FRP laminate increases during cyclic loading, caused by matrix cracking. The results indicate that the proposed method successfully provides fatigue crack detection for basalt FRP laminate composite pipes.

  10. Penstock failure detection system at the "Valsan" hydro power plant

    NASA Astrophysics Data System (ADS)

    Georgescu, A. M.; Coşoiu, C. I.; Alboiu, N.; Hlevca, D.; Tataroiu, R.; Popescu, O.

    2012-11-01

    "Valsan" is a small Hydro Power Plant, 5 MW, situated at about 160 km north of Bucharest, Romania, on the small "Valsan" river in a remote mountainous area. It is equipped with a single Francis turbine. The penstock is located in the access shaft of the HPP. "Hidroelectrica", the Romanian company that operates the HPP, was trying to implement a remote penstock failure detection system. Starting from a classic hydraulic problem, the authors of the paper derived a method for failure detection and localization on the pipe. The method assumes the existence of 2 flow meters and 2 pressure transducers at the inlet and outlet of the pressurized pipe. Calculations have to be based on experimental values measured in a permanent regime for different values of the flow rate. The method was at first tested on a pipe, in the Hydraulic Laboratory of the Technical University of Civil Engineering Bucharest. Pipe failure was modelled by opening of a valve on a tee branch of the analyzed pipe. Experimental results were found to be in good agreement with theoretical ones. The penstock of the "Valsan" HPP, was modelled in EPANET, in order to: i) test the method at a larger scale; ii) get the right flow and pressure transducers that are needed to implement it. At the request of "Hidroelectrica" a routine that computes the efficiency of the turbine was added to the monitoring software. After the system was implemented, another series of measurements were performed at the site in order to validate it. Failure was modelled by opening an existing valve on a branch of the penstock. Detection of the failure was correct and almost instantaneous, while failure location was accurate within 5% of the total penstock length.

  11. Evaluation of a rinsing-based cleaning process for pipes.

    PubMed

    Prosek, Mirko; Krizman, Mitja; Kovac, Miso

    2005-07-01

    Pipes of various designs were constructed. Pipes were filled with a model solution resembling a dermal solution product. After the removal of the model solution, pipes were rinsed several times with ethanol and rinsing solutions of each step analyzed by gas chromatography. The results gave the information about the dependency between the configuration of the pipe and the efficiency of the cleaning operation. From concentrations measured in the reactor, expected concentrations in rinsing solutions from pipes were predicted. The obtained results confirm that the amount of residues per surface area increases when a pipe includes bends and valves. In terms of extra contamination, each bend was equal to 25 cm, while each valve was equal to 100 cm of pipe length when pipes of 1.8 cm in diameter were used. It was proven that the contributions of individual valves and bends in the pipe are additive in the calculation. The validity of the proposed model was confirmed by experimental data.

  12. High Energy Vibration for Gas Piping

    NASA Astrophysics Data System (ADS)

    Lee, Gary Y. H.; Chan, K. B.; Lee, Aylwin Y. S.; Jia, ShengXiang

    2017-07-01

    In September 2016, a gas compressor in offshore Sarawak has its rotor changed out. Prior to this change-out, pipe vibration study was carried-out by the project team to evaluate any potential high energy pipe vibration problems at the compressor’s existing relief valve downstream pipes due to process condition changes after rotor change out. This paper covers high frequency acoustic excitation (HFAE) vibration also known as acoustic induced vibration (AIV) study and discusses detailed methodologies as a companion to the Energy Institute Guidelines for the avoidance of vibration induced fatigue failure, which is a common industry practice to assess and mitigate for AIV induced fatigue failure. Such detailed theoretical studies can help to minimize or totally avoid physical pipe modification, leading to reduce offshore plant shutdown days to plant shutdowns only being required to accommodate gas compressor upgrades, reducing cost without compromising process safety.

  13. Natural gas transport by plastic pipes. (Latest citations from the Compendex database). Published Search

    SciTech Connect

    Not Available

    1993-07-01

    The bibliography contains citations concerning the use of plastic piping to transport natural gas or liquid propane gas. The interaction between gas odorants and plastic pipe, the effects of aging on plastic pipe used to transport gas, and pipe failure analyses are examined. Bending, joining, and repair methods are discussed. Composite reinforced plastic pipes and plastic coated pipes are considered. Polyethylene and epoxy composites are among the materials discussed. Gas main upgrading projects that replaced old pipes with plastic ones are briefly cited. (Contains a minimum of 88 citations and includes a subject term index and title list.)

  14. Risk based management of piping systems

    SciTech Connect

    Conley, M.J.; Aller, J.E.; Tallin, A.; Weber, B.J.

    1996-07-01

    The API Piping Inspection Code is the first such Code to require classification of piping based on the consequences of failure, and to use this classification to influence inspection activity. Since this Code was published, progress has been made in the development of tools to improve on this approach by determining not only the consequences of failure, but also the likelihood of failure. ``Risk`` is defined as the product of the consequence and the likelihood. Measuring risk provides the means to formally manage risk by matching the inspection effort (costs) to the benefits of reduced risk. Using such a cost/benefit analysis allows the optimization of inspection budgets while meeting societal demands for reduction of the risk associated with process plant piping. This paper presents an overview of the tools developed to measure risk, and the methods to determine the effects of past and future inspections on the level of risk. The methodology is being developed as an industry-sponsored project under the direction of an API committee. The intent is to develop an API Recommended Practice that will be linked to In-Service Inspection Standards and the emerging Fitness for Service procedures. Actual studies using a similar approach have shown that a very high percentage of the risk due to piping in an operating facility is associated with relatively few pieces of piping. This permits inspection efforts to be focused on those piping systems that will result in the greatest risk reduction.

  15. Ultrasonic pipe assessment

    DOEpatents

    Thomas, Graham H.; Morrow, Valerie L.; Levie, Harold; Kane, Ronald J.; Brown, Albert E.

    2003-12-23

    An ultrasonic pipe or other structure assessment system includes an ultrasonic transducer positioned proximate the pipe or other structure. A fluid connection between the ultrasonic transducer and the pipe or other structure is produced. The ultrasonic transducer is moved relative to the pipe or other structure.

  16. The Sacred Calf Pipe.

    ERIC Educational Resources Information Center

    Simms, Thomas E.

    1987-01-01

    Tells how the author learned of and recorded the list of Sioux tribe members who have kept the White Buffalo Calf Pipe. Reviews the legend surrounding the origin of the pipe and describes the succession of pipe-keepers and how they inherit the pipe. (Author/AEM)

  17. Shield For Flexible Pipe

    NASA Technical Reports Server (NTRS)

    Ponton, Michael K.; Williford, Clifford B.; Lagen, Nicholas T.

    1995-01-01

    Cylindrical shield designed to fit around flexible pipe to protect nearby workers from injury and equipment from damage if pipe ruptures. Designed as pressure-relief device. Absorbs impact of debris ejected radially from broken flexible pipe. Also redirects flow of pressurized fluid escaping from broken pipe onto flow path allowing for relief of pressure while minimizing potential for harm.

  18. Deployable Pipe-Z

    NASA Astrophysics Data System (ADS)

    Zawidzki, Machi

    2016-10-01

    This paper presents a concept of deployable Pipe-Z (dPZ): a modular structural system which takes advantage of the robustness of rigid-panel mechanism and allows to create free-form links which are also reconfigurable and deployable. The concept presented can be applied for building habitats and infrastructures for human exploration of oceans and outer space. dPZ structures can adapt to changing requirements e.g. mission objectives, crew condition and technological developments. Furthermore, such lightweight and adaptable structural concept can assist in sustainable exploration development. After brief introduction, the concept of Pipe-Z (PZ) is presented. Next, the reconfigurability of PZ is explained and illustrated with continuous and collision-free transition from a PZ forming a Trefoil knot to a Figure-eight knot. The following sections introduce, explain and illustrate the folding mechanism of a single foldable Pipe-Z module (fPZM) and entire dPZ structure. The latter is illustrated with asynchronous (delayed) unfolding of a relatively complex Unknot. Several applications of PZ are suggested, namely for underwater and deep-space and surface habitats, for permanent, but in particular, temporary or emergency passages. As an example, a scenario of a failure of one of the modules of the International Space Station is presented where a rigid structure of 40 fPZMs bypasses the ;dead link;. A low-fidelity prototype of a 6-module octagonal dPZ is presented; several folding schemes including concentric toric rings are demonstrated. Practical issues of pressurization and packing are briefly discussed.

  19. Mathematical modeling of high and low temperature heat pipes

    NASA Technical Reports Server (NTRS)

    Chi, S. W.

    1971-01-01

    Following a review of heat and mass transfer theory relevant to heat pipe performance, math models are developed for calculating heat-transfer limitations of high-temperature heat pipes and heat-transfer limitations and temperature gradient of low temperature heat pipes. Calculated results are compared with the available experimental data from various sources to increase confidence in the present math models. Complete listings of two computer programs for high- and low-temperature heat pipes respectively are included. These programs enable the performance to be predicted of heat pipes with wrapped-screen, rectangular-groove, or screen-covered rectangular-groove wick.

  20. Optimizing the Pipe Diameter of the Pipe Belt Conveyor Based on Discrete Element Method

    NASA Astrophysics Data System (ADS)

    Guo, Yong-cun; Wang, Shuang; Hu, Kun; Li, De-yong

    2016-03-01

    In order to increase the transport volume of the pipe belt conveyor and reduce lateral pressure of the supporting roller set, this study aims to optimize the pipe diameter of the pipe belt conveyor. A mechanical model of the pipe belt conveyor with six supporting roller sets in the belt bearing section was built based on the infinitesimal method, and the formula for calculating the lateral pressure of each supporting roller was deduced on the basis of reasonable assumption. Simulated analysis was carried out on the operation process of the pipe belt conveyor by using the discrete element method. The result showed that, when the other conditions were certain, as the pipe diameter increased, the average lateral pressure of the supporting roller set increased, with a gradually decreasing increment, which was consistent with the calculated result of the theoretical formula. An optimized pipe diameter under the current conditions was obtained by fitting the curve of the formula for calculating the transport volume of the pipe belt conveyor and its simulation curve. It provided a certain reference value for improving the transport efficiency and prolonging the service life of the pipe belt conveyor.

  1. Fabrication and Testing of a Leading-Edge-Shaped Heat Pipe

    NASA Technical Reports Server (NTRS)

    Glass, David E.; Merrigan, Michael A.; Sena, J. Tom; Reid, Robert S.

    1998-01-01

    The development of a refractory-composite/heat-pipe-cooled leading edge has evolved from the design stage to the fabrication and testing of a full size, leading-edge-shaped heat pipe. The heat pipe had a 'D-shaped' cross section and was fabricated from arc cast Mo-4lRe. An artery was included in the wick. Several issues were resolved with the fabrication of the sharp leading edge radius heat pipe. The heat pipe was tested in a vacuum chamber at Los Alamos National Laboratory using induction heating and was started up from the frozen state several times. However, design temperatures and heat fluxes were not obtained due to premature failure of the heat pipe resulting from electrical discharge between the induction heating apparatus and the heat pipe. Though a testing anomaly caused premature failure of the heat pipe, successful startup and operation of the heat pipe was demonstrated.

  2. Copper-nickel piping reduces costs, biofouling/corrosion

    SciTech Connect

    Albaugh, E.K.

    1984-11-01

    Seawater piping systems for offshore drilling rigs and platforms are typically plagued by biofouling and/or corrosion, with piping failures occurring in only a few years. Discussed are alternate pipe materials with the emphasis on the testing of a copper-nickel alloy in the Gulf of Mexico. Results show that although initially more expensive, use of this alloy can extend system life to 20 years or more while improving productivity and reducing overall costs when compared to a comparable steel system.

  3. Wall thinning criteria for low temperature-low pressure piping. Task 91-030-1

    SciTech Connect

    Mertz, G.E.

    1993-01-01

    This acceptance criteria is intended to prevent gross rupture or rapidly propagating failure during normal and abnormal operating conditions. Pitting may be present in the carbon steel piping. While the acceptance criteria have provisions to preclude gross rupture through a pitted region, they do not protect against throughwall pit growth and subsequent leakage. Potential leakage through a pit in low pressure piping is less than the post-DBE design basis leakage. Both the uniform thinning and LTA criteria protect against leakage, since their potential for leakage is larger. The acceptance criteria protects against gross rupture due to general wall thinning, local wall thinning (LTA`s), pitting, and fracture through weld defects. General wall thinning calculations are based on the restart criteria, SEP-24. LTA criteria for hoop stresses are based on ASME Code Case N-480 {open_quotes}Examination Requirements for Pipe Wall Thinning Due to Single Phase Erosion and Corrosion{close_quotes}. The LTA criteria for axial stress is based on an effective average thickness concept, which prevents plastic collapse of a locally thinned pipe. Limits on pit density, based on an effective cross section concept, are used to prevent gross rupture through a group of pits. The CEGB R-6 failure assessment diagram is used in the fracture evaluation, along with postulated weld defects. This criteria is intended for low temperature, low pressure piping systems. Corrosion and/or weld defects increase the peak stresses during normal operation and may lead to a reduction in fatigue life. Piping systems subject to significant thermal or mechanical fatigue will require additional analysis which is beyond the scope of this document.

  4. Probability of pipe fracture in the primary coolant loop of a PWR plant. Volume 5. Probabilistic fracture mechanics analysis. Load Combination Program Project I final report

    SciTech Connect

    Harris, D.O.; Lim, E.Y.; Dedhia, D.D.

    1981-06-01

    The primary purpose of the Load Combination Program covered in this report is to estimate the probability of a seismic induced LOCA in the primary piping of a commercial pressurized water reactor (PWR). Best estimates, rather than upper bound results are desired. This was accomplished by use of a fracture mechanics model that employs a random distribution of initial cracks in the piping welds. Estimates of the probability of cracks of various sizes initially existing in the welds are combined with fracture mechanics calculations of how these cracks would grow during service. This then leads to direct estimates of the probability of failure as a function of time and location within the piping system. The influence of varying the stress history to which the piping is subjected is easily determined. Seismic events enter into the analysis through the stresses they impose on the pipes. Hence, the influence of various seismic events on the piping failure probability can be determined, thereby providing the desired information.

  5. Flexible ocean upwelling pipe

    DOEpatents

    Person, Abraham

    1980-01-01

    In an ocean thermal energy conversion facility, a cold water riser pipe is releasably supported at its upper end by the hull of the floating facility. The pipe is substantially vertical and has its lower end far below the hull above the ocean floor. The pipe is defined essentially entirely of a material which has a modulus of elasticity substantially less than that of steel, e.g., high density polyethylene, so that the pipe is flexible and compliant to rather than resistant to applied bending moments. The position of the lower end of the pipe relative to the hull is stabilized by a weight suspended below the lower end of the pipe on a flexible line. The pipe, apart from the weight, is positively buoyant. If support of the upper end of the pipe is released, the pipe sinks to the ocean floor, but is not damaged as the length of the line between the pipe and the weight is sufficient to allow the buoyant pipe to come to a stop within the line length after the weight contacts the ocean floor, and thereafter to float submerged above the ocean floor while moored to the ocean floor by the weight. The upper end of the pipe, while supported by the hull, communicates to a sump in the hull in which the water level is maintained below the ambient water level. The sump volume is sufficient to keep the pipe full during heaving of the hull, thereby preventing collapse of the pipe.

  6. Power source for wireless sensors in pipes

    NASA Astrophysics Data System (ADS)

    Keddis, Sherif; Schwesinger, Norbert

    2016-04-01

    In this paper, we present investigations on wireless sensors for fluid control inside a pipe. Autarkic sensors are in the technical trend. They are typically connected with a transceiver unit for data transmission. Sensors usually need a lower amount of energy than data transceivers. Therefore, they are commonly supplied via wires or batteries with electricity. With common technologies, this request leads to high requirements on tightness in liquids since poor sealing could easily lead to failures. Replacement of batteries inside pipes is complicated and almost accompanied by a flow interruption. The application of energy harvesters as power supply is therefore a good alternative. In our studies we used flexible piezoelectric energy harvesters of PVDF (Poly-Vinylidene-Di-Fluoride). All harvesting units consist of piezoelectric PVDF-foils as active layers and Aluminum-foils as electrodes. The layers were stacked alternating on each other and wound to a spool. A LDPE-film wraps the spool and prevents the inflow of liquids. The device has following parameters:

  7. No. of windings: 4 in air, 4, 5, 7 in water
  8. Dimensions: 15 mm Ø 22mm
  9. Materials: PDVF: 25μm Aluminimum: 6μm, LDPE: 25μm
  10. A ring shaped bluff body was placed inside the pipe to induce turbulence in the fluid stream. As the harvesters have been arranged downstream of the bluff body, they were forced to oscillate independent of the media. In each case, deformation of the active layers led to a polarization and a separation of electrical charges. Experiments were carried out in a wind channel as well as in a water pipe. In air, the spool oscillates with a frequency of about 30Hz, at a wind speed of about 7m/s. A -Voltage of about 4V (peak-peak) was measured. This delivers in case of power adjustment, power values of about 0.54μW. In water, the velocity of the fluid was limited to nearly one tenth. Oscillation starts only at a water speed above 0.6m/s. The average oscillation

  11. Static analysis of a piping system with elbows

    SciTech Connect

    Bryan, B.J.

    1994-03-01

    Vibration tests of elbows to failure were performed in Japan in the early 1970s. The piping system included two elbows and an eccentric mass. Tests were run both pressurized and unpressurized. This report documents a static analysis of the piping system in which the elbows are subjected to out of plane bending. The effects of internal pressure and material plasticity are investigated.

  12. Reusable pipe flange covers

    DOEpatents

    Holden, James Elliott; Perez, Julieta

    2001-01-01

    A molded, flexible pipe flange cover for temporarily covering a pipe flange and a pipe opening includes a substantially round center portion having a peripheral skirt portion depending from the center portion, the center portion adapted to engage a front side of the pipe flange and to seal the pipe opening. The peripheral skirt portion is formed to include a plurality of circumferentially spaced tabs, wherein free ends of the flexible tabs are formed with respective through passages adapted to receive a drawstring for pulling the tabs together on a back side of the pipe flange.

  13. Using the 2011 Mw9.0 Tohoku earthquake to test the Coulomb stress triggering hypothesis and to calculate faults brought closer to failure

    USGS Publications Warehouse

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

    2011-01-01

    The 11 March 2011 Tohoku Earthquake provides an unprecedented test of the extent to which Coulomb stress transfer governs the triggering of aftershocks. During 11-31 March, there were 177 aftershocks with focal mechanisms, and so the Coulomb stress change imparted by the rupture can be resolved on the aftershock nodal planes to learn whether they were brought closer to failure. Numerous source models for the mainshock have been inverted from seismic, geodetic, and tsunami observations. Here, we show that, among six tested source models, there is a mean 47% gain in positively-stressed aftershock mechanisms over that for the background (1997-10 March 2011) earthquakes, which serve as the control group. An aftershock fault friction of 0.4 is found to fit the data better than 0.0 or 0.8, and among all the tested models, Wei and Sladen (2011) produced the largest gain, 63%. We also calculate that at least 5 of the seven large, exotic, or remote aftershocks were brought ≥0.3 bars closer to failure. With these tests as confirmation, we calculate that large sections of the Japan trench megathrust, the outer trench slope normal faults, the Kanto fragment beneath Tokyo, and the Itoigawa-Shizuoka Tectonic Line, were also brought ≥0.3 bars closer to failure.

  14. Analysis of the Effects of External Detonations on Piping Systems

    SciTech Connect

    Vincent, III, A M

    2001-03-07

    This paper analyzes the effects of blast pressure on wall mounted piping, tubing and conduits and draws conclusions regarding the failure of these systems under the anticipated blast loading conditions in an existing nuclear facility.

  15. Metallurgical investigation of material from chill-water piping system

    SciTech Connect

    Alexander, D.J.

    1990-02-01

    The mechanical properties and microstructures of two steel pipes that were removed from the Oak Ridge National Laboratory (ORNL) chill-water system have been studied. Concerns for low-stress failure of aging pipes prompted a metallurgical investigation to determine the risk of using a cryogenic freeze-plug technique to isolate a section of piping for repair. The two pipes, designated S and L, were low-alloy carbon steel, with microstructures of ferrite and pearlite. Pipe S had a small grain size and a banded microstructure, whereas pipe L had a larger grain size with less pearlite, which was randomly spaced. Pipe S had a ductile-to-brittle transition temperature (DBTT) of 0{degree}C, compared to 84{degree}C for pipe L. Because of the high transition temperature and the very low level of the lower shelf, cooling to liquid-nitrogen temperature resulted in a very small margin of safety for these pipes. Therefore, this technique is not recommended for the pipe materials, and caution is advised in applying this technique to any pipe with unknown toughness properties. 8 figs., 2 tabs.

  16. Sound design of chimney pipes by optimization of their resonators.

    PubMed

    Rucz, Péter; Trommer, Thomas; Angster, Judit; Miklós, András; Augusztinovicz, Fülöp

    2013-01-01

    An optimization method, based on an acoustic waveguide model of chimney and resonator, was developed and tested by laboratory measurements of experimental chimney pipes. The dimensions of the chimney pipes are modified by the optimization algorithm until the specified fundamental frequency is achieved, and a predetermined harmonic partial overlaps with an eigenfrequency of the pipe. The experimental pipes were dimensioned by the optimization method for four different scenarios and were built by an organ builder. The measurements show excellent agreement between the measured sound spectra and calculated input admittances. The developed optimization method can be used for sound design of chimney pipes.

  17. Pipe selection guide

    SciTech Connect

    Sanders, R.D.

    1982-04-01

    Four parameters are used to define a particular pipe: inside diameter, wall thickness, material, and ends. The factors influencing pipe selection are limited to fluid pressure, temperature, chemistry, flow rate, and cost. Other pipe parameters and factors that influence pipe selection and design are mentioned, and, where appropriate, the user is warned that at some stage in the project these factors must be dealt with. It is assumed that the objective is the direct application of geothermal water at temperatures lower than 200/sup 0/F and with 12-in. or smaller pipe. When considering friction losses for sizing purposes, only straight pipe is considered. A discussion of the characteristics and attributes of readily available pipe is included to aid in making a preliminary selection. Energy loss from buried pipe is considered.

  18. Treatment Planning System Calculation Errors Are Present in Most Imaging and Radiation Oncology Core-Houston Phantom Failures.

    PubMed

    Kerns, James R; Stingo, Francesco; Followill, David S; Howell, Rebecca M; Melancon, Adam; Kry, Stephen F

    2017-08-01

    The anthropomorphic phantom program at the Houston branch of the Imaging and Radiation Oncology Core (IROC-Houston) is an end-to-end test that can be used to determine whether an institution can accurately model, calculate, and deliver an intensity modulated radiation therapy dose distribution. Currently, institutions that do not meet IROC-Houston's criteria have no specific information with which to identify and correct problems. In the present study, an independent recalculation system was developed to identify treatment planning system (TPS) calculation errors. A recalculation system was commissioned and customized using IROC-Houston measurement reference dosimetry data for common linear accelerator classes. Using this system, 259 head and neck phantom irradiations were recalculated. Both the recalculation and the institution's TPS calculation were compared with the delivered dose that was measured. In cases in which the recalculation was statistically more accurate by 2% on average or 3% at a single measurement location than was the institution's TPS, the irradiation was flagged as having a "considerable" institutional calculation error. The error rates were also examined according to the linear accelerator vendor and delivery technique. Surprisingly, on average, the reference recalculation system had better accuracy than the institution's TPS. Considerable TPS errors were found in 17% (n=45) of the head and neck irradiations. Also, 68% (n=13) of the irradiations that failed to meet the IROC-Houston criteria were found to have calculation errors. Nearly 1 in 5 institutions were found to have TPS errors in their intensity modulated radiation therapy calculations, highlighting the need for careful beam modeling and calculation in the TPS. An independent recalculation system can help identify the presence of TPS errors and pass on the knowledge to the institution. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Evolution of non-condensable gas in ammonia heat pipes

    NASA Technical Reports Server (NTRS)

    Richter, Robert

    1990-01-01

    Accumulation of noncondensible gas (NCG) has been observed in ammonia heat pipes. NCG has been found to be detrimental to the performance of heat pipes and can result in complete operational failure. A kinetic and thermodynamic analysis has been performed that evaluates the dissociation of ammonia under various conditions and predicts the amount of NCG present in heat pipes. The analysis indicates that the observed NCG in ammonia heat pipes can be attributed to the dissociation of ammonia into its constituents, hydrogen and nitrogen. It shows time and temperature to be the important parameters, in conjunction with the catalytic characteristic of the container material.

  20. Mechanical integrity and piping systems -- The forgotten elements

    SciTech Connect

    Miller, S.D.; Uscocovich, J.S.

    1996-07-01

    Many codes and regulations address the issue of process piping inspections, the most recent being AP1570. OSH1910.119 paragraph (j) also contains requirements for maintaining the mechanical integrity of an operating system through inspections and tests. This paper includes details for an examination approach dealing with process piping as a system, including often neglected items such as piping supports and expansion joints. A training methodology will be discussed which incorporates site walkdowns, operating history, typical failures and other items which may be used to formulate a site specific and flexible program to ensure safe and reliable piping systems as well as compliance with OSHA 1910.119 paragraph (j).

  21. Effects of Pipe Wall Mass Distribution in Line-of-Sight Nuclear Tests.

    DTIC Science & Technology

    1978-08-01

    helical lead ribbon ( spiral asymmetry) was placed around the pipe , the tar- get plate suffered only negligible damage. No conclusive ex- planation has been...the third calculation, a mass of iron equal to that used in the spiral case was placed symmetrically around the pipe . In slab geometry this corresponds...demonstrated that for explosively collapsed pipes , spiral asymmetries appear to significantly reduce the jetting down the pipe . In the "no pipe flow

  22. Heat pipes. [technology utilization

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The development and use of heat pipes are described, including space requirements and contributions. Controllable heat pipes, and designs for automatically maintaining a selected constant temperature, are discussed which would add to the versatility and usefulness of heat pipes in industrial processing, manufacture of integrated circuits, and in temperature stabilization of electronics.

  23. Singing Corrugated Pipes

    ERIC Educational Resources Information Center

    Crawford, Frank S.

    1974-01-01

    Presents theoretical and experimental observations made with a musical toy called Hummer consisting of a corrugated flexible plastic tube about three-feet long and one-inch diam open at both ends. Included are descriptions of three new instruments: the Water Pipe, the Gas-Pipe Corrugahorn Bugle, and the Gas-Pipe Blues Corrugahorn. (CC)

  24. Computer program determines gas flow rates in piping systems

    NASA Technical Reports Server (NTRS)

    Franke, R.

    1966-01-01

    Computer program calculates the steady state flow characteristics of an ideal compressible gas in a complex piping system. The program calculates the stagnation and total temperature, static and total pressure, loss factor, and forces on each element in the piping system.

  1. Heat transfer model of above and underground insulated piping systems

    SciTech Connect

    Kwon, K.C.

    1998-07-01

    A simplified heat transfer model of above and underground insulated piping systems was developed to perform iterative calculations for fluid temperatures along the entire pipe length. It is applicable to gas, liquid, fluid flow with no phase change. Spreadsheet computer programs of the model have been developed and used extensively to perform the above calculations for thermal resistance, heat loss and core fluid temperature.

  2. Uncertainty analysis for probabilistic pipe fracture evaluations in LBB applications

    SciTech Connect

    Rahman, S.; Ghadiali, N.; Wilkowski, G.

    1997-04-01

    During the NRC`s Short Cracks in Piping and Piping Welds Program at Battelle, a probabilistic methodology was developed to conduct fracture evaluations of circumferentially cracked pipes for application to leak-rate detection. Later, in the IPIRG-2 program, several parameters that may affect leak-before-break and other pipe flaw evaluations were identified. This paper presents new results from several uncertainty analyses to evaluate the effects of normal operating stresses, normal plus safe-shutdown earthquake stresses, off-centered cracks, restraint of pressure-induced bending, and dynamic and cyclic loading rates on the conditional failure probability of pipes. systems in BWR and PWR. For each parameter, the sensitivity to conditional probability of failure and hence, its importance on probabilistic leak-before-break evaluations were determined.

  3. Toward Active Monitoring of Piping Using Ultrasonic Guided Waves

    SciTech Connect

    Park, Joon-Soo; Kim, Young H.; Song, Sung-Jin; Kim, Jae-Hee; Eom, Heung-Seop; Im, Kwang-Hee

    2004-02-26

    Piping in nuclear power plants is exposed to severe environmental conditions so that it is very susceptible to failure caused by the growth of defects. Thus, it is necessary to have thorough inspection of piping in order to detect defects before failure. Unfortunately, however, inspection of piping in nuclear power plants is not easy in practice because of its long length as well as the radioactive environment. To take care of this difficulty, a research endeavor to develop techniques to monitor piping in nuclear power plants continuously and actively using ultrasonic guided wave is currently undertaken. This paper reports initial results of our endeavor including design of an ultrasonic array system for active monitoring of piping.

  4. Natural gas transport by plastic pipes. (Latest citations from the EI Compendex*plus database). Published Search

    SciTech Connect

    Not Available

    1994-12-01

    The bibliography contains citations concerning the use of plastic piping to transport natural gas or liquid propane gas. The interaction between gas odorants and plastic pipe, the effects of aging on plastic pipe used to transport gas, and pipe failure analyses are examined. Bending, joining, and repair methods are discussed. Composite reinforced plastic pipes and plastic coated pipes are considered. Polyethylene and epoxy composites are among the materials discussed. Gas main upgrading projects that replaced old pipes with plastic ones are briefly cited. (Contains a minimum of 91 citations and includes a subject term index and title list.)

  5. Natural gas transport by plastic pipes. (Latest citations from the EI Compendex*plus database). Published Search

    SciTech Connect

    1996-03-01

    The bibliography contains citations concerning the use of plastic piping to transport natural gas or liquid propane gas. The interaction between gas odorants and plastic pipe, the effects of aging on plastic pipe used to transport gas, and pipe failure analyses are examined. Bending, joining, and repair methods are discussed. Composite reinforced plastic pipes and plastic coated pipes are considered. Polyethylene and epoxy composites are among the materials discussed. Gas main upgrading projects that replaced old pipes with plastic ones are briefly cited. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  6. Natural gas transport by plastic pipes. (Latest citations from the EI Compendex*plus database). Published Search

    SciTech Connect

    Not Available

    1994-05-01

    The bibliography contains citations concerning the use of plastic piping to transport natural gas or liquid propane gas. The interaction between gas odorants and plastic pipe, the effects of aging on plastic pipe used to transport gas, and pipe failure analyses are examined. Bending, joining, and repair methods are discussed. Composite reinforced plastic pipes and plastic coated pipes are considered. Polyethylene and epoxy composites are among the materials discussed. Gas main upgrading projects that replaced old pipes with plastic ones are briefly cited. (Contains a minimum of 89 citations and includes a subject term index and title list.)

  7. Acoustic characteristics of circular bends in pipes

    NASA Astrophysics Data System (ADS)

    Firth, D.; Fahy, F. J.

    1984-11-01

    The acoustic properties of circular bends in pipework systems are investigated by calculation of the mode shapes and propagation constants of the acoustic modes of the bend, the torus modes, and by evaluation of the transmission and reflection coefficients at a bend in an otherwise infinite straight pipe. The coefficients for the first three cylinder and torus modes are plotted against frequency for the case of a plane wave incident upon a 90° bend. The pipe walls are assumed to be rigid.

  8. Pipe Line Control

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The array of tanks, pipes and valves in the photo below is a petroleum tank farm in Georgia, part of a petrochemical pipe line system that moves refined petroleum products from Texas and Louisiana to the mid-Eastern seaboard. The same pipes handle a number of different products, such as gasoline, kerosene, jet fuel or fuel oil. The fluids are temporarily stored in tanks, pumped into the pipes in turn and routed to other way stations along the pipe line. The complex job of controlling, measuring and monitoring fuel flow is accomplished automatically by a computerized control and communications system which incorporates multiple space technologies.

  9. Common causes of material degradation in buried piping

    SciTech Connect

    Jenkins, C.F.

    1997-01-20

    Buried pipe may fail for innumerable reasons. Causes can be mechanical damage/breakage, chemically initiated corrosion, or a combination. Failures may originate either internally or externally on the pipe. They may be related to flaws in the design, to excessive or unanticipated internal pressure or ground level loading, and/or to poor or uncertain installation practice. Or the pipe may simply ``wear out`` in service. Steel is strong and very forgiving in underground applications, especially with regard to backfill. However, soil support developed through densification or compaction is critical for brittle concrete and vitrified clay tile pipe, and is very important for cast iron and plastic pipe. Chemistry of the soil determines whether or not it will enhance corrosion or other types of degradation. Various causes and mechanisms for deterioration of buried pipe are indicated. Some peculiarities of the different materials of construction are characterized. Repair methods and means to circumvent special problems are described.

  10. Fracture behavior under monotonic and low cycle loadings in carbon steel pipes and welded pipe joints with a defect

    SciTech Connect

    Miyazaki, Katsumasa; Kanno, Satoshi; Hayashi, Makoto; Ishiwata, Masayuki; Gotoh, Nobuho; Miura, Naoki; Fujioka, Terutaka; Kashima, Koichi

    1996-12-01

    To evaluate the structural integrity of power plant piping during earthquakes, fracture behavior under monotonic and low cycle loadings was examined, using 4-inch carbon steel pipes made of base metal and welded pipe joints with a circumferential defect at room and elevated temperatures in air. In the monotonic bending tests, the maximum loads increased slightly with the loading rates for base metal pipes and welded pipe joints. The maximum loads in welded pipe joints were about 10% higher than those in base metal pipes for various displacement rate. In the cyclic bending tests, the number of cycles to failure, N{sub f} was closely correlated with the ratio of the load amplitude, Pa to the maximum load, Pmax obtained in the monotonic bending tests, in spite of the difference in the maximum loads for base metal pipes and welded pipe joints. The number of loading cycles during an earthquake was assumed as about 100 cycles in design. The relationship between Pa/Pmax and the number of cycles to failure showed that the allowable load amplitude ratio was estimated as about 0.7.

  11. Polymer concrete lined pipe for use in geothermal applications

    SciTech Connect

    Kaeding, Albert O.

    1982-10-08

    A specific polymer concrete formulation was applied as a steel pipe liner in response to a need for durable, economical materials for use in contact with high temperature geothermal brine. Compressive strengths of up to 165.8 MPa and splitting tensile strengths of 23.5 MPa were measured at ambient temperature. Compressive strengths of 24 MPa and splitting tensile strengths of 2.5 MPa were measured at about 150 C. Cost of piping a geothermal plant with PC and PC-lined steel pipe is calculated to be $1.21 million, which compares favorably with a similar plant piped with alloy steel piping at a cost of $1.33 million. Life-cycle cost analysis indicates that the cost of PC-lined steel pipe would be 82% of that of carbon steel pipe over a 20-year plant operating life.

  12. Mathematical modeling of high and low temperature heat pipes

    NASA Technical Reports Server (NTRS)

    Chi, S. W.

    1971-01-01

    Mathematical models are developed for calculating heat-transfer limitations of high-temperature heat pipes and heat-transfer limitations and temperature gradient of low temperature heat pipes. Calculated results are compared with the available experimental data from various sources to increase confidence in the present math models. Complete listings of two computer programs for high- and low-temperature heat pipes respectively are appended. These programs enable the performance of heat pipes with wrapped-screen, rectangular-groove or screen-covered rectangular-groove wick to be predicted.

  13. 65. FIRE SUPPRESSION PIPES BEHIND FLAME BUCKET. PIPES TO UMBILICAL ...

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

    65. FIRE SUPPRESSION PIPES BEHIND FLAME BUCKET. PIPES TO UMBILICAL MAST IN LOWER LEFT CORNER; PIPES TO LAUNCHER IN UPPER LEFT CORNER; PIPES TO FLAME BUCKET IN LOWER RIGHT CORNER OF PHOTOGRAPH. POTABLE WATER PIPING IN UPPER RIGHT CORNER OF PHOTO. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  14. 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.

  15. Qualitative failure of a multiconfiguration method in prolate spheroidal coordinates in calculating dissociative photoionization of H2+

    NASA Astrophysics Data System (ADS)

    Haxton, Daniel J.; Lawler, Keith V.; McCurdy, C. William

    2015-06-01

    A formulation of a multiconfiguration time-dependent Hartree-Fock (MCTDHF) method with nuclear motion is tested by application to a three-body breakup problem, the dissociative photoionization cross section of the H2+ ion. The representation of the wave function in terms of a set of Slater determinants used for all nuclear geometries, with a prescribed parametric dependence upon the nuclear geometry such that the cusps follow the nuclei, times a complete basis expansion in the nuclear degrees of freedom shows promise as a method for treating nonadiabatic electronic and nuclear motion in molecules. However, the method used here for diatomics, in which the parametric dependence is prescribed through the choice of prolate spheroidal coordinates, produces qualitatively incorrect steplike behavior in the calculated cross section near onset. Modifications to the prolate spheroidal coordinate system that would improve this nonadiabatic diatomic MCTDHF representation are proposed.

  16. Crack instability analysis methods for leak-before-break program in piping systems

    SciTech Connect

    Mattar Neto, M.; Nobrega, P.G.B. da

    1995-11-01

    The instability evaluation of cracks in piping systems is a step that is considered when a high-energy line is investigated in a leak-before-break (LBB) program. Different approaches have been used to assess stability of cracks: (a) local flow stress (LFS); (b) limit load (LL); (c) elastic-plastic fracture mechanics (EPFM) as J-integral versus tearing modulus (J-T) analysis. The first two methods are used for high ductile materials, when it is assumed that remaining ligament of the cracked pipe section becomes fully plastic prior to crack extension. EPFM is considered for low ductile piping when the material reaches unstable ductile tearing prior to plastic collapse in the net section. In this paper the LFS, LL and EPFM J-T methodologies were applied to calculate failure loads in circumferential through-wall cracked pipes with different materials, geometries and loads. It presents a comparison among the results obtained from the above three formulations and also compares them with experimental data available in the literature.

  17. Development and Testing of Insulated Drill Pipe

    SciTech Connect

    Champness, T.; Finger, J.; Jacobson, R.

    1999-07-07

    This project has comprised design, analysis, laboratory testing, and field testing of insulated drill pipe (IDP). This paper will briefly describe the earlier work, but will focus on results from the recently-completed field test in a geothermal well. Field test results are consistent with earlier analyses and laboratory tests, all of which support the conclusion that insulated drill pipe can have a very significant effect on circulating fluid temperatures. This will enable the use of downhole motors and steering tools in hot wells, and will reduce corrosion, deterioration of drilling fluids, and heat-induced failures in other downhole components.

  18. Titanium-potassium heat pipe corrosion studies

    SciTech Connect

    Lundberg, L.B.

    1984-07-01

    An experimental study of the susceptibility of wickless titanium/potassium heat pipes to corrosive attack has been conducted in vacuo at 800/sup 0/K for 6511h and at 900/sup 0/K for 4797h without failure or degradation. Some movement of carbon, nitrogen and oxygen was observed in the titanium container tube, but no evidence of attack could be detected in metallographic cross sections of samples taken along the length of the heat pipes. The lack of observable attack of titanium by potassium under these conditions refutes previous reports of Ti-K incompatibility.

  19. Deformability of molybdenum during the production of thin-wall pipes

    NASA Astrophysics Data System (ADS)

    Smirnov, S. V.; Nesterenko, A. V.; Shveikin, V. P.

    2008-10-01

    The deformation properties of commercial-purity MChVP molybdenum are studied. Plasticity diagrams that relate the limiting strain to failure to the state-of-stress indices are constructed. The plasticity of the material is found to depend substantially on the type of state of stress, which is characterized by the Lode parameter. The plasticity of the material is analyzed under alternating deformation conditions. A damage theory is used to study the healing of the deformation-induced damage during annealing and to determine the conditions under which irreversible damage, which cannot be healed by heat treatment, appears. The simulation results are used to analyze the damage accumulation during the production of thin-wall pipes. The plasticity margin is found to decrease most strongly during the multipass pressing of a pipe workpiece in a punch. As follows from the damage calculation results, intermediate annealing between pressing passes should be introduced at a size of 18 × 3.1 mm.

  20. Standard problems to evaluate piping response computer codes

    SciTech Connect

    Bezler, P.; Subudhi, M.

    1984-01-01

    A program has been underway to evaluate the analysis methods used by industry to qualify nuclear power plant piping. Two objectives of this program are to develop physical benchmarks for validating the accuracy of computer codes used to simulate piping response and to develop improved procedures for calculating the response of multiple supported piping with independent seismic inputs. The status of the program in these two areas is reviewed.

  1. 46 CFR 154.520 - Piping calculations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... allowable stress values under § 56.07-10 of this chapter and, if the design temperature is −110 °C (−166 °F) or lower, the stress analysis must be specially approved by the Commandant (CG-522) and must...

  2. 46 CFR 154.520 - Piping calculations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... allowable stress values under § 56.07-10 of this chapter and, if the design temperature is −110 °C (−166 °F) or lower, the stress analysis must be specially approved by the Commandant (CG-522) and must...

  3. 46 CFR 154.520 - Piping calculations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... allowable stress values under § 56.07-10 of this chapter and, if the design temperature is −110 °C (−166 °F) or lower, the stress analysis must be specially approved by the Commandant (CG-ENG) and must...

  4. Polyvinylchloride (PVC) pipe hazards

    SciTech Connect

    Not Available

    1983-01-01

    PVC pipe should be used only for low pressure liquid systems where the liquid is at or near ambient temperature. PVC pipe, because of its brittle nature, should be used only in unmanned areas or where it is isolated from personnel. It should be otherwise protected so that it is not subjected to ultraviolet light, temperature cycling or damage after installation. Heat (particularly welding and cutting) should be avoided in the immediate vicinity of the piping. PVC pipe should not be used where it would be subject to vibration. The effects of certain chemicals on PVC should be carefully considered, both where the pipe is a carrying medium for the chemical and where the pipe may be exposed to the chemicals externally.

  5. Deployable Heat Pipe Radiator

    NASA Technical Reports Server (NTRS)

    Edelstein, F.

    1975-01-01

    A 1.2- by 1.8-m variable conductance heat pipe radiator was designed, built, and tested. The radiator has deployment capability and can passively control Freon-21 fluid loop temperatures under varying loads and environments. It consists of six grooved variable conductance heat pipes attached to a 0.032-in. aluminum panel. Heat is supplied to the radiator via a fluid header or a single-fluid flexible heat pipe header. The heat pipe header is an artery design that has a flexible section capable of bending up to 90 degrees. Radiator loads as high as 850 watts were successfully tested. Over a load variation of 200 watts, the outlet temperature of the Freon-21 fluid varied by 7 F. An alternate control system was also investigated which used a variable conductance heat pipe header attached to the heat pipe radiator panel.

  6. Miniature Heat Pipes

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Small Business Innovation Research contracts from Goddard Space Flight Center to Thermacore Inc. have fostered the company work on devices tagged "heat pipes" for space application. To control the extreme temperature ranges in space, heat pipes are important to spacecraft. The problem was to maintain an 8-watt central processing unit (CPU) at less than 90 C in a notebook computer using no power, with very little space available and without using forced convection. Thermacore's answer was in the design of a powder metal wick that transfers CPU heat from a tightly confined spot to an area near available air flow. The heat pipe technology permits a notebook computer to be operated in any position without loss of performance. Miniature heat pipe technology has successfully been applied, such as in Pentium Processor notebook computers. The company expects its heat pipes to accommodate desktop computers as well. Cellular phones, camcorders, and other hand-held electronics are forsible applications for heat pipes.

  7. DETAIL OF CONNECTION PIPES AND PIPE SUPPORT ROLLERS, LOOKING EAST. ...

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

    DETAIL OF CONNECTION PIPES AND PIPE SUPPORT ROLLERS, LOOKING EAST. PIPES AND CRANKS IN BACKGROUND ARE FOR TURNOUTS (L-R) 25, 29, AND 27. - Baltimore & Ohio Railroad, Z Tower, State Route 46, Keyser, Mineral County, WV

  8. Abrasion resistant heat pipe

    DOEpatents

    Ernst, D.M.

    1984-10-23

    A specially constructed heat pipe is described for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.

  9. Dehumidifying Heat Pipe

    NASA Technical Reports Server (NTRS)

    Khattar, Mukesh K.

    1993-01-01

    U-shaped heat pipe partly dehumidifies air leaving air conditioner. Fits readily in air-handling unit of conditioner. Evaporator and condenser sections of heat pipe consist of finned tubes in comb pattern. Each tube sealed at one end and joined to manifold at other. Sections connected by single pipe carrying vapor to condenser manifold and liquid to evaporator manifold. Simple on/off or proportional valve used to control flow of working fluid. Valve actuated by temperature/humidity sensor.

  10. Abrasion resistant heat pipe

    DOEpatents

    Ernst, Donald M.

    1984-10-23

    A specially constructed heat pipe for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.

  11. Heat Pipe Planets

    NASA Technical Reports Server (NTRS)

    Moore, William B.; Simon, Justin I.; Webb, A. Alexander G.

    2014-01-01

    When volcanism dominates heat transport, a terrestrial body enters a heat-pipe mode, in which hot magma moves through the lithosphere in narrow channels. Even at high heat flow, a heat-pipe planet develops a thick, cold, downwards-advecting lithosphere dominated by (ultra-)mafic flows and contractional deformation at the surface. Heat-pipes are an important feature of terrestrial planets at high heat flow, as illustrated by Io. Evidence for their operation early in Earth's history suggests that all terrestrial bodies should experience an episode of heat-pipe cooling early in their histories.

  12. Introduction to Heat Pipes

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2015-01-01

    This is the presentation file for the short course Introduction to Heat Pipes, to be conducted at the 2015 Thermal Fluids and Analysis Workshop, August 3-7, 2015, Silver Spring, Maryland. NCTS 21070-15. Course Description: This course will present operating principles of the heat pipe with emphases on the underlying physical processes and requirements of pressure and energy balance. Performance characterizations and design considerations of the heat pipe will be highlighted. Guidelines for thermal engineers in the selection of heat pipes as part of the spacecraft thermal control system, testing methodology, and analytical modeling will also be discussed.

  13. Heat Pipe Materials Compatibility

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.; Fleischman, G. L.; Luedke, E. E.

    1976-01-01

    An experimental program to evaluate noncondensable gas generation in ammonia heat pipes was completed. A total of 37 heat pipes made of aluminum, stainless steel and combinations of these materials were processed by various techniques, operated at different temperatures and tested at low temperature to quantitatively determine gas generation rates. In order of increasing stability are aluminum/stainless combination, all aluminum and all stainless heat pipes. One interesting result is the identification of intentionally introduced water in the ammonia during a reflux step as a means of surface passivation to reduce gas generation in stainless-steel/aluminum heat pipes.

  14. External artery heat pipe

    NASA Technical Reports Server (NTRS)

    Gernert, Nelson J. (Inventor); Ernst, Donald M. (Inventor); Shaubach, Robert M. (Inventor)

    1989-01-01

    An improved heat pipe with an external artery. The longitudinal slot in the heat pipe wall which interconnects the heat pipe vapor space with the external artery is completely filled with sintered wick material and the wall of the external artery is also covered with sintered wick material. This added wick structure assures that the external artery will continue to feed liquid to the heat pipe evaporator even if a vapor bubble forms within and would otherwise block the liquid transport function of the external artery.

  15. Pipe crawler apparatus

    DOEpatents

    Hovis, Gregory L.; Erickson, Scott A.; Blackmon, Bruce L.

    2002-01-01

    A pipe crawler apparatus particularly useful for 3-inch and 4-inch diameter pipes is provided. The pipe crawler apparatus uses a gripping apparatus in which a free end of a piston rod is modified with a bearing retaining groove. Bearings, placed within the groove, are directed against a camming surface of three respective pivoting support members. The non-pivoting ends of the support members carry a foot-like gripping member that, upon pivoting of the support member, engages the interior wall of the pipe.

  16. Heat pipe investigations

    NASA Technical Reports Server (NTRS)

    Marshburn, J. P.

    1972-01-01

    The OAO-C spacecraft has three circular heat pipes, each of a different internal design, located in the space between the spacecraft structural tube and the experiment tube, which are designed to isothermalize the structure. Two of the pipes are used to transport high heat loads, and the third is for low heat loads. The test problems deal with the charging of the pipes, modifications, the mobile tilt table, the position indicator, and the heat input mechanisms. The final results showed that the techniques used were adequate for thermal-vacuum testing of heat pipes.

  17. Internal pipe attachment mechanism

    DOEpatents

    Bast, R.M.; Chesnut, D.A.; Henning, C.D.; Lennon, J.P.; Pastrnak, J.W.; Smith, J.A.

    1994-12-13

    An attachment mechanism is described for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection. 6 figures.

  18. Internal pipe attachment mechanism

    DOEpatents

    Bast, Richard M.; Chesnut, Dwayne A.; Henning, Carl D.; Lennon, Joseph P.; Pastrnak, John W.; Smith, Joseph A.

    1994-01-01

    An attachment mechanism for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection.

  19. Variable-Conductance Heat Pipes

    NASA Technical Reports Server (NTRS)

    Antoniuk, D.

    1986-01-01

    In response to need to accurately and efficiently predict performance of variable-conductance heat pipes (VCHP's) incorporated in spacecraft thermalcontrol systems, computer code VCHPDA developed to interact with thermal analyzer programs such as SINDA (Systems Improved Numerical Differencing Analyzer). Calculates length of gas-blocked region and vapor temperature in active portion. Advantages of VCHPDA over prior programs improved accuracy, unconditional stability, and increased efficiency of solution resulting from novel approach and use of state-of-the-art numerical techniques for solving VCHP mathematical model. Code valuable tool in design and evaluation of advanced thermal-control systems using variable-conductance heat pipes. Written in FORTRAN IV for use on CDC 600 computers.

  20. Optimal replacement policy for single pipes in water distribution networks

    NASA Astrophysics Data System (ADS)

    Luong, Huynh T.; Nagarur, Nagen N.

    2001-12-01

    In the actual operation of a distribution network, failure can occur in any component of the network, such as pumps, valves, junctions, and pipes. When a component is experiencing failure, the question raised is whether to replace or repair it. For the case of a pipe in the distribution network, which is one of the most frequently subject-to-failure components, there are some aspects that still remain unresolved in relation to practical operations of a maintenance program. In this research paper, a mathematical model is developed which aims to support a decision to repair or replace a main pipe in the state of failure. The objective of the model is to maximize the long-run availability of the pipe under some budget constraints. A semi-Markov process is used to depict the behavior of the pipe, and replacement ages of the pipe in each of its deteriorating stages are taken as the decision variables. The original nonlinear problem resulting from model formulation is converted to a linear problem by some simple transformations, and then numerical experiments are conducted to illustrate the applicability of the proposed model.

  1. Heat pipe reactors for space power applications

    NASA Technical Reports Server (NTRS)

    Koenig, D. R.; Ranken, W. A.; Salmi, E. W.

    1977-01-01

    A family of heat pipe reactors design concepts has been developed to provide heat to a variety of electrical conversion systems. Three power plants are described that span the power range 1-500 kWe and operate in the temperature range 1200-1700 K. The reactors are fast, compact, heat-pipe cooled, high-temperature nuclear reactors fueled with fully enriched refractory fuels, UC-ZrC or UO2. Each fuel element is cooled by an axially located molybdenum heat pipe containing either sodium or lithium vapor. Virtues of the reactor designs are the avoidance of single-point failure mechanisms, the relatively high operating temperature, and the expected long lifetimes of the fuel element components.

  2. Heat pipe reactors for space power applications

    NASA Technical Reports Server (NTRS)

    Koenig, D. R.; Ranken, W. A.; Salmi, E. W.

    1977-01-01

    A family of heat pipe reactors design concepts has been developed to provide heat to a variety of electrical conversion systems. Three power plants are described that span the power range 1-500 kWe and operate in the temperature range 1200-1700 K. The reactors are fast, compact, heat-pipe cooled, high-temperature nuclear reactors fueled with fully enriched refractory fuels, UC-ZrC or UO2. Each fuel element is cooled by an axially located molybdenum heat pipe containing either sodium or lithium vapor. Virtues of the reactor designs are the avoidance of single-point failure mechanisms, the relatively high operating temperature, and the expected long lifetimes of the fuel element components.

  3. Performance of large diameter polyvinyl chloride (PVC) pipes in water applications

    NASA Astrophysics Data System (ADS)

    Deshmukh, Pradip P.

    Polyvinyl chloride (PVC) pipes are used in water management utilities to manage safe and efficient water transport. The material's advantages includes strength, flexibility, anti-corrosive properties and easy installation methods. The disadvantages include joint failure, pipe fractures, material contamination and oxidative degradation. This thesis evaluates the use of 24 inch and larger diameter PVC pipes in water management utilities. Center of Undergraduate Infrastructure and Research Education (CUIRE) conducted surveys consisting of questions pertaining to PVC pipe material and installation practices to different water management utilities. While PVC material is most commonly used in pipelines less than 24", the CUIRE responses show that PVC pipes are not the most common type of pipe material in 24" and larger diameters installed in the facilities for various reasons. These reasons are discussed and evaluated in hopes of understanding the material's fallbacks in the piping industry. Finally, future research recommendations are constructed for researchers in the PVC piping industry.

  4. Short cracks in piping and piping welds. Seventh program report, March 1993-December 1994. Volume 4, Number 1

    SciTech Connect

    Wilkowski, G.M.; Ghadiali, N.; Rudland, D.; Krishnaswamy, P.; Rahman, S.; Scott, P.

    1995-04-01

    This is the seventh progress report of the U.S. Nuclear Regulatory Commission`s research program entitled {open_quotes}Short Cracks in Piping and Piping Welds{close_quotes}. The program objective is to verify and improve fracture analyses for circumferentially cracked large-diameter nuclear piping with crack sizes typically used in leak-before-break (LBB) analyses and in-service flaw evaluations. All work in the eight technical tasks have been completed. Ten topical reports are scheduled to be published. Progress only during the reporting period, March 1993 - December 1994, not covered in the topical reports is presented in this report. Details about the following efforts are covered in this report: (1) Improvements to the two computer programs NRCPIPE and NRCPIPES to assess the failure behavior of circumferential through-wall and surface-cracked pipe, respectively; (2) Pipe material property database PIFRAC; (3) Circumferentially cracked pipe database CIRCUMCK.WKI; (4) An assessment of the proposed ASME Section III design stress rule changes on pipe flaw tolerance; and (5) A pipe fracture experiment on a section of pipe removed from service degraded by microbiologically induced corrosion (MIC) which contained a girth weld crack. Progress in the other tasks is not repeated here as it has been covered in great detail in the topical reports.

  5. Analysis of chlorinated polyvinyl chloride pipe burst problems :Vasquez residence system inspection.

    SciTech Connect

    Black, Billy D.; Menicucci, David F.; Harrison, John

    2005-10-01

    This report documents the investigation regarding the failure of CPVC piping that was used to connect a solar hot water system to standard plumbing in a home. Details of the failure are described along with numerous pictures and diagrams. A potential failure mechanism is described and recommendations are outlined to prevent such a failure.

  6. On the generation of helical waves in circular pipe flow

    NASA Astrophysics Data System (ADS)

    Landman, Michael J.

    1990-05-01

    The question of the existence of helical waves in fluid flow through a circular pipe is discussed. In the case of pipe flow forced only by an axial pressure gradient, direct simulations have failed to find any self-sustaining helical waves. The effect of residual swirl in the inlet flow is investigated, by performing linear stability calculations and direct simulations of a forced basic flow. The results are qualitatively similar to that of flow in a rotating pipe, in which stable helical waves are known to exist. These results suggest that residual rotation may be an important mechanism in triggering laminar-turbulent transition in circular pipe flow.

  7. Fluid flow and heat transfer in polygonal micro heat pipes

    NASA Astrophysics Data System (ADS)

    Rao, Sai; Wong, Harris

    2015-11-01

    Micro heat pipes have been used to cool microelectronic devices, but their heat transfer coefficients are low compared with those of conventional heat pipes. We model heat and mass transfer in triangular, square, hexagonal, and rectangular micro heat pipes under small imposed temperature differences. A micro heat pipe is a closed microchannel filled with a wetting liquid and a long vapor bubble. When a temperature difference is applied across a micro heat pipe, the equilibrium vapor pressure at the hot end is higher than that at the cold end, and the difference drives a vapor flow. As the vapor moves, the vapor pressure at the hot end drops below the saturation pressure. This pressure drop induces continuous evaporation from the interface. Two dimensionless numbers emerge from the momentum and energy equations: the heat-pipe number H, and the evaporation exponent S. When H >> 1 and S >> 1, vapor-flow heat transfer dominates and a thermal boundary layer appears at the hot end, the thickness of which scales as L/S, where L is the half-length of the pipe. A similar boundary layer exists at the cold end. Outside the boundary layers, the temperature is uniform. We also find a dimensionless optimal pipe length Sm =Sm(H) for maximum evaporative heat transfer. Thus, our model suggests that micro heat pipes should be designed with H >> 1 and S =Sm. We calculate H and S for four published micro-heat-pipe experiments, and find encouraging support for our design criterion.

  8. Transient multidimensional analysis of nonconventional heat pipes with uniform and nonuniform heat distributions

    NASA Technical Reports Server (NTRS)

    Cao, Y.; Faghri, A.

    1991-01-01

    A numerical analysis of transient heat pipe performance including nonconventional heat pipes with nonuniform heat distributions is presented. A body-fitted grid system was applied to a three-dimensional wall and wick model, which was coupled with a transient compressible quasi-one-dimensional vapor flow model. The numerical results were first compared with experimental data from cylindrical heat pipes with good agreement. Numerical calculations were then made for a leading edge heat pipe with localized high heat fluxes. Performance characteristics different from conventional heat pipes are illustrated and some operating limits concerning heat pipe design are discussed.

  9. These Pipes Are "Happening"

    ERIC Educational Resources Information Center

    Skophammer, Karen

    2010-01-01

    The author is blessed with having the water pipes for the school system in her office. In this article, the author describes how the breaking of the pipes had led to a very worthwhile art experience for her students. They practiced contour and shaded drawing techniques, reviewed patterns and color theory, and used their reasoning skills--all while…

  10. These Pipes Are "Happening"

    ERIC Educational Resources Information Center

    Skophammer, Karen

    2010-01-01

    The author is blessed with having the water pipes for the school system in her office. In this article, the author describes how the breaking of the pipes had led to a very worthwhile art experience for her students. They practiced contour and shaded drawing techniques, reviewed patterns and color theory, and used their reasoning skills--all while…

  11. Heat pipe methanator

    DOEpatents

    Ranken, William A.; Kemme, Joseph E.

    1976-07-27

    A heat pipe methanator for converting coal gas to methane. Gravity return heat pipes are employed to remove the heat of reaction from the methanation promoting catalyst, transmitting a portion of this heat to an incoming gas pre-heat section and delivering the remainder to a steam generating heat exchanger.

  12. Unstable heat pipes

    SciTech Connect

    McGuinness, M.J.; Pruess, K.

    1987-10-01

    Heat pipes are an important feature of models of vapor-dominated geothermal reservoirs. Numerical experiments reveal that a vapor-dominated heat pipe is unstable if pressure is controlled at shallow levels. This instability is discussed in physical terms, and some implications for geothermal reservoirs are considered. 9 refs., 10 figs.

  13. Splayed mirror light pipes

    SciTech Connect

    Swift, P.D.

    2010-02-15

    An expression is given for the transmission of the rectangular-section mirror light pipe. The expression is used to model throughputs for simulated solar conditions over a calender year. It is found that the splaying of a mirror light pipe results in a significant increase in throughputs particularly in winter months. (author)

  14. Friction loss in straight pipes of unplasticized polyvinyl chloride.

    PubMed

    Iwasaki, T; Ojima, J

    1996-01-01

    In order to design proper ductwork for a local exhaust system, airflow characteristics were investigated in straight pipes of unplasticized polyvinyl chloride (PVC). A linear decrease in static pressure was observed downstream at points from the opening of the VU pipes (JIS K 6741) located at distances greater than 10 times the pipe diameter, for velocities ranging between 10.18-36.91 m/s. Roughness inside pipes with small diameters was found to be 0.0042-0.0056 mm and the friction factor was calculated on the basis of Colebrook's equation for an airflow transition zone. An extended friction chart was then constructed on the basis of the roughness value and the friction factor. This chart can be applied when designing a local exhaust system with the ducts of diameters ranging from 40 to 900 mm. The friction loss of the PVC pipe was found to be approximately 2/3 of that of a galvanized steel pipe.

  15. Biplastic pipes for high-pressure oil pipeline systems

    NASA Astrophysics Data System (ADS)

    Anoshkin, A. N.; Tashkinov, A. A.; Larionov, A. F.; Pospelov, A. B.

    2000-05-01

    A high-performance, corrosion-resistant biplastic pipe for high-pressure oil pipeline systems is presented. The pipe combines an outer load-carrying layer formed from unidirectionally glass-reinforced plastic (GRP) sublayers by wet multi-circuit winding and an inner sealing layer of high-density polyethylene. Both demountable and permanent joints, tees, and other parts are constructed for these pipes. The biplastic pipes ensure reliable operation of oil pipeline systems under a pressure of up to 200 bar. The experimental results and calculated estimates of the strength of biplastic pipes are presented. The results of using these pipes in oil pipeline systems in the Perm' region are discussed.

  16. 12 May 2008 M = 7.9 Wenchuan, China, earthquake calculated to increase failure stress and seismicity rate on three major fault systems

    USGS Publications Warehouse

    Toda, S.; Lin, J.; Meghraoui, M.; Stein, R.S.

    2008-01-01

    The Wenchuan earthquake on the Longmen Shan fault zone devastated cities of Sichuan, claiming at least 69,000 lives. We calculate that the earthquake also brought the Xianshuihe, Kunlun and Min Jiang faults 150-400 km from the mainshock rupture in the eastern Tibetan Plateau 0.2-0.5 bars closer to Coulomb failure. Because some portions of these stressed faults have not ruptured in more than a century, the earthquake could trigger or hasten additional M > 7 earthquakes, potentially subjecting regions from Kangding to Daofu and Maqin to Rangtag to strong shaking. We use the calculated stress changes and the observed background seismicity to forecast the rate and distribution of damaging shocks. The earthquake probability in the region is estimated to be 57-71% for M ??? 6 shocks during the next decade, and 8-12% for M ??? 7 shocks. These are up to twice the probabilities for the decade before the Wenchuan earthquake struck. Copyright 2008 by the American Geophysical Union.

  17. Drag reduction properties of superhydrophobic mesh pipes

    NASA Astrophysics Data System (ADS)

    Geraldi, Nicasio R.; Dodd, Linzi E.; Xu, Ben B.; Wells, Gary G.; Wood, David; Newton, Michael I.; McHale, Glen

    2017-09-01

    Even with the recent extensive study into superhydrophobic surfaces, the fabrication of such surfaces on the inside walls of a pipe remains challenging. In this work we report a convenient bi-layered pipe design using a thin superhydrophobic metallic mesh formed into a tube, supported inside another pipe. A flow system was constructed to test the fabricated bi-layer pipeline, which allowed for different constant flow rates of water to be passed through the pipe, whilst the differential pressure was measured, from which the drag coefficient (ƒ) and Reynolds numbers (Re) were calculated. Expected values of ƒ were found for smooth glass pipes for the Reynolds number (Re) range 750-10 000, in both the laminar and part of the turbulent regimes. Flow through plain meshes without the superhydrophobic coating were also measured over a similar range (750  <  Re  <  14 000). After applying the superhydrophobic coating, ƒ was found for 4000  <  Re  <  14 000 and was found to be less than that of an uncoated mesh, but greater than that of a smooth glass pipe of the same diameter. This demonstrates that a superhydrophobic mesh can support a plastron and provide a drag reduction compared to a plain mesh, however, the plastron is progressively destroyed with use and in particular at higher flow rates.

  18. Analysis of Rotary Bayonets and Piping

    SciTech Connect

    Chess, K.; Wendlandt, J.; /Fermilab

    1988-08-19

    This report quantifies certain characteristics of the rotary bayonets and associated platform piping on the DO detector. The Vacuum Jacketed 4-inch x 6-inch and 1.5-inch x 3-inch and the 4-inch and 6-inch vacuum pipe articulating jumpers are considered here. The values of greatest importance are the forces required at the bayonet moment arms given in Table II and the stresses summarized in Table III. The forces required should be noted and checked that they are acceptable to the problem. The maximum bending stresses of the vacuum pipes do not exceed 1000 psi and are essentially negligible. The 4-inch x 6-inch vacuum jacketed line experiences the maximum bending stress of 10,300 psi. According to code B31.1, the maximum allowable bending stress is 25,500 psi. The major sources of error in these calculations should be summarized. First, all weights used were approximations and all lengths used were scaled from drawings. Second, while the FRAME MAC{trademark} models resemble the vacuum pipe articulating jumpers, they are definitely simplified. For instance, they do not account for the different stiffnesses of the unions. Finally, the bayonets in the ANSYS models consist of an outer jacket and an inner pipe fixed together at the end of the male sleeve. The actual bayonets are more complex and are composed of various sizes of tubes and pipes which affect the stiffness of the section.

  19. Application of bounding spectra to seismic design of piping based on the performance of above ground piping in power plants subjected to strong motion earthquakes

    SciTech Connect

    Stevenson, J.D.

    1995-02-01

    This report extends the potential application of Bounding Spectra evaluation procedures, developed as part of the A-46 Unresolved Safety Issue applicable to seismic verification of in-situ electrical and mechanical equipment, to in-situ safety related piping in nuclear power plants. The report presents a summary of earthquake experience data which define the behavior of typical U.S. power plant piping subject to strong motion earthquakes. The report defines those piping system caveats which would assure the seismic adequacy of the piping systems which meet those caveats and whose seismic demand are within the bounding spectra input. Based on the observed behavior of piping in strong motion earthquakes, the report describes the capabilities of the piping system to carry seismic loads as a function of the type of connection (i.e. threaded versus welded). This report also discusses in some detail the basic causes and mechanisms for earthquake damages and failures to power plant piping systems.

  20. The monster sound pipe

    NASA Astrophysics Data System (ADS)

    Ruiz, Michael J.; Perkins, James

    2017-03-01

    Producing a deep bass tone by striking a large 3 m (10 ft) flexible corrugated drainage pipe immediately grabs student attention. The fundamental pitch of the corrugated tube is found to be a semitone lower than a non-corrugated smooth pipe of the same length. A video (https://youtu.be/FU7a9d7N60Y) of the demonstration is included, which illustrates how an Internet keyboard can be used to estimate the fundamental pitches of each pipe. Since both pipes have similar end corrections, the pitch discrepancy between the smooth pipe and drainage tube is due to the corrugations, which lower the speed of sound inside the flexible tube, dropping its pitch a semitone.

  1. Extendable pipe crawler

    DOEpatents

    Hapstack, M.

    1991-05-28

    A pipe crawler is described having a front leg assembly and a back leg assembly connected together by two air cylinders, each leg assembly having four extendable legs and a pair of actuators for sliding the extendable legs radially outward to increase the range of the legs when the pipe crawler enters a section of a pipe having a larger diameter. The crawler crawls by inchworm'-like motion, the front leg assembly and back leg assembly alternately engaging and disengaging the wall of the pipe to hold the pipe crawler as the air cylinders alternately advance the front leg assembly and bring up the rear leg assembly. The pair of actuators of each leg assembly are parallel, adjacent and opposing acting so that each slides two adjacent extendable legs radially outward. 5 figures.

  2. Extendable pipe crawler

    DOEpatents

    Hapstack, Mark

    1991-01-01

    A pipe crawler having a front leg assembly and a back leg assembly connected together by two air cylinders, each leg assembly having four extendable legs and a pair of actuators for sliding the extendable legs radially outward to increase the range of the legs when the pipe crawler enters a section of a pipe having a larger diameter. The crawler crawls by "inchworm"-like motion, the front leg assembly and back leg assembly alternately engaging and disengaging the wall of the pipe to hold the pipe crawler as the air cylinders alternately advance the front leg assembly and bring up the rear leg assembly. The pair of actuators of each leg assembly are parallel, adjacent and opposing acting so that each slides two adjacent extendable legs radially outward.

  3. Autogenous Metallic Pipe Leak Repair in Potable Water Systems.

    PubMed

    Tang, Min; Triantafyllidou, Simoni; Edwards, Marc A

    2015-07-21

    Copper and iron pipes have a remarkable capability for autogenous repair (self-repair) of leaks in potable water systems. Field studies revealed exemplars that metallic pipe leaks caused by nails, rocks, and erosion corrosion autogenously repaired, as confirmed in the laboratory experiments. This work demonstrated that 100% (N = 26) of 150 μm leaks contacting representative bulk potable water in copper pipes sealed autogenously via formation of corrosion precipitates at 20-40 psi, pH 3.0-11.0, and with upward and downward leak orientations. Similar leaks in carbon steel pipes at 20 psi self-repaired at pH 5.5 and 8.5, but two leaks did not self-repair permanently at pH 11.0 suggesting that water chemistry may control the durability of materials that seal the leaks and therefore the permanence of repair. Larger 400 μm holes in copper pipes had much lower (0-33%) success of self-repair at pH 3.0-11.0, whereas all 400 μm holes in carbon steel pipes at 20 psi self-repaired at pH 4.0-11.0. Pressure tests indicated that some of the repairs created at 20-40 psi ambient pressure could withstand more than 100 psi without failure. Autogenous repair has implications for understanding patterns of pipe failures, extending the lifetime of decaying infrastructure, and developing new plumbing materials.

  4. Natural gas transport by plastic pipes. January 1970-October 1988 (Citations from the Compendex data base). Report for January 1970-October 1988

    SciTech Connect

    Not Available

    1988-11-01

    This bibliography contains citations concerning the use of plastic piping to transport natural gas or liquid propane gas. The interaction between gas odorants and plastic pipe, the effects of aging on plastic pipe used to transport gas, and pipe-failure analyses are examined. Bending, joining, and repair methods are discussed. Composite-reinforced plastic pipes and plastic coated pipes are considered. Polyethylene and epoxy composites are among the materials discussed. Gas-main upgrading projects that replaced old pipes with plastic ones are briefly cited. (Contains 77 citations fully indexed and including a title list.)

  5. Leaks in pipe networks

    USGS Publications Warehouse

    Pudar, Ranko S.; Liggett, James A.

    1992-01-01

    Leak detection in water-distribution systems can be accomplished by solving an inverse problem using measurements of pressure and/or flow. The problem is formulated with equivalent orifice areas of possible leaks as the unknowns. Minimization of the difference between measured and calculated heads produces a solution for the areas. The quality of the result depends on number and location of the measurements. A sensitivity matrix is key to deciding where to make measurements. Both location and magnitude of leaks are sensitive to the quantity and quality of pressure measurements and to how well the pipe friction parameters are known. The overdetermined problem (more measurements than suspected leaks) gives the best results, but some information can be derived from the underdetermined problem. The variance of leak areas, based on the quality of system characteristics and pressure data, indicates the likely accuracy of the results. The method will not substitute for more traditional leak surveys but can serve as a guide and supplement.

  6. SHAM: High-level seismic tests of piping at the HDR

    SciTech Connect

    Kot, C.A.; Srinivasan, M.G.; Hsieh, B.J.; Malcher, L.; Schrammel, D.; Steinhilber, H.; Costello, J.F.

    1988-01-01

    As part of the second phase of vibrational/earthquake investigations at the HDR (Heissdampfreaktor) Test Facility in Kahl/Main, FRG, high-level simulated seismic tests (SHAM) were performed during April--May 1988 on the VKL (Versuchskreislauf) in-plant piping system with two servohydraulic actuators, each capable of generating 40 tons of force. The purpose of these experiments was to study the behavior of piping subjected to seismic excitation levels that exceed design levels manifold and may result in failure/plastification of pipe supports and pipe elements, and to establish seismic margins for piping and pipe supports. The performance of six different dynamic pipe support systems was compared in these tests and the response, operability, and fragility of dynamic supports and of a typical US gate valve were investigated. Data obtained in the tests are used to validate analysis methods. Very preliminary evaluations lead to the observation that, in general, failures of dynamic supports (in particular snubbers) occur only at load levels that substantially exceed the design capacity. Pipe strains at load levels exceeding the design level threefold are quite small, and even when exceeding the design level eightfold are quite tolerable. Hence, under seismic loading, even at extreme levels and in spite of multiple support failures, pipe failure is unlikely. 5 refs., 16 figs.

  7. Flexible ultrasonic pipe inspection apparatus

    DOEpatents

    Jenkins, C.F.; Howard, B.D.

    1994-01-01

    Pipe crawlers, pipe inspection {open_quotes}rabbits{close_quotes} and similar vehicles are widely used for inspecting the interior surfaces of piping systems, storage tanks and process vessels for damaged or flawed structural features. This paper describes the design of a flexible, modular ultrasonic pipe inspection apparatus.

  8. Experimenting with a "Pipe" Whistle

    ERIC Educational Resources Information Center

    Stafford, Olga

    2012-01-01

    A simple pipe whistle can be made using pieces of PVC pipe. The whistle can be used to measure the resonant frequencies of open or closed pipes. A slightly modified version of the device can be used to also investigate the interesting dependence of the sound frequencies produced on the orifice-to-edge distance. The pipe whistle described here…

  9. Experimenting with a "Pipe" Whistle

    ERIC Educational Resources Information Center

    Stafford, Olga

    2012-01-01

    A simple pipe whistle can be made using pieces of PVC pipe. The whistle can be used to measure the resonant frequencies of open or closed pipes. A slightly modified version of the device can be used to also investigate the interesting dependence of the sound frequencies produced on the orifice-to-edge distance. The pipe whistle described here…

  10. Seam-weld quality of modern ERW/HFI line pipe

    SciTech Connect

    Groeneveld, T.P.; Barnes, C.R.

    1991-09-01

    This study was undertaken to determine whether the seam-weld quality of modern ERW (electric resistance-welded)/HFI (high-frequency induction) welded pipe has been improved and justifies more widespread use of this type of pipe in critical applications. Wider use of ERW/HFI line pipe in gas-transmission lines would be expected to reduce construction costs. Five recently produced, heavy wall pipes fabricated using high-frequency electric-resistance welding (ERW) processes to make the seam weld and one pipe fabricated using the high-frequency induction (HFI) welding process to make the seam weld were studied. Four of the pipes were Grade X-60, one was Grade X-65, and one was Grade X-70. All of the pipes were produced from microalloyed, controlled-rolled steels, and the weld zones were post-weld normalized. Ultrasonic inspection of the seam welds in the six pipe sections evaluated revealed no indications of defects. The tensile properties of all of the weld zones exceeded the minimum specified yield strengths for the respective grades of pipe and all of the pipes exhibited ductile failures either in the weld zone or in the base metal. Five of the six pipes exhibited ductile failures either in the weld zone or in the base metal. Five of the six pipes exhibited relatively low 85% shear area transition temperatures and relatively high upper-shelf energy absorptions as determined with Charpy V-notch specimens. In addition, for two of the three joints of pipe for which the properties were determined at both ends of the pipe, the tensile and impact properties showed little variation from end-to-end. However, for the other joint of pipe, the impact properties varied substantially from one end to the other.

  11. Electrohydrodynamic heat pipes.

    NASA Technical Reports Server (NTRS)

    Jones, T. B.

    1973-01-01

    An electrohydrodynamic heat pipe of radical design is proposed which substitutes polarization electrohydrodynamic force effects for capillarity in collecting, guiding, and pumping a condensate liquid phase. The discussed device is restricted to the use of dielectric liquids as working fluids. Because of the relatively poor thermal transport properties of these liquids, capillary heat pipes using these liquids have not been high performance devices. The employment of the electrohydrodynamic concept should enhance this performance and help fill the performance gap that exists in the temperature range from 250 F to 750 F for 'conventional' capillary heat pipes.

  12. Gas pipe explorer robot

    NASA Technical Reports Server (NTRS)

    Wilcox, Brian (Inventor)

    2004-01-01

    A gas pipe explorer formed of a plurality of connecting elements, and an articulation element between the connected elements. The connected elements include drive capabilities, and the articulation element allows the connected elements to traverse gas pipes of arbitrary shapes and sizes. A sensor may sends the characteristics of the gas pipe, and the communication element may send back those sends characteristics. The communication can be wired, over a tether connecting the device to a remote end. Alternatively, the connection can be wireless, driven by either a generator or a battery.

  13. Improved Thin, Flexible Heat Pipes

    NASA Technical Reports Server (NTRS)

    Rosenfeld, John H.; Gernert, Nelson J.; Sarraf, David B.; Wollen, Peter J.; Surina, Frank C.; Fale, John E.

    2004-01-01

    Flexible heat pipes of an improved type are fabricated as layers of different materials laminated together into vacuum- tight sheets or tapes. In comparison with prior flexible heat pipes, these flexible heat pipes are less susceptible to leakage. Other advantages of these flexible heat pipes, relative to prior flexible heat pipes, include high reliability and greater ease and lower cost of fabrication. Because these heat pipes are very thin, they are highly flexible. When coated on outside surfaces with adhesives, these flexible heat pipes can be applied, like common adhesive tapes, to the surfaces of heat sinks and objects to be cooled, even if those surfaces are curved.

  14. AutoPIPE Extract Program

    SciTech Connect

    Cline, Barbara E.

    1993-07-02

    The AutoPIPE Extract Program (APEX) provides an interface between CADAM (Computer Aided Design and Manufacturing) Release 21 drafting software and the AutoPIPE, Version 4.4, piping analysis program. APEX produces the AutoPIPE batch input file that corresponds to the piping shown in a CADAM model. The card image file contains header cards, material cards, and pipe cross section cards as well as tee, bend, valve, and flange cards. Node numbers are automatically generated. APEX processes straight pipe, branch lines and ring geometries.

  15. Refined pipe theory for mechanistic modeling of wood development.

    PubMed

    Deckmyn, Gaby; Evans, Sam P; Randle, Tim J

    2006-06-01

    We present a mechanistic model of wood tissue development in response to changes in competition, management and climate. The model is based on a refinement of the pipe theory, where the constant ratio between sapwood and leaf area (pipe theory) is replaced by a ratio between pipe conductivity and leaf area. Simulated pipe conductivity changes with age, stand density and climate in response to changes in allocation or pipe radius, or both. The central equation of the model, which calculates the ratio of carbon (C) allocated to leaves and pipes, can be parameterized to describe the contrasting stem conductivity behavior of different tree species: from constant stem conductivity (functional homeostasis hypothesis) to height-related reduction in stem conductivity with age (hydraulic limitation hypothesis). The model simulates the daily growth of pipes (vessels or tracheids), fibers and parenchyma as well as vessel size and simulates the wood density profile and the earlywood to latewood ratio from these data. Initial runs indicate the model yields realistic seasonal changes in pipe radius (decreasing pipe radius from spring to autumn) and wood density, as well as realistic differences associated with the competitive status of trees (denser wood in suppressed trees).

  16. Heat pipe manufacturing study

    NASA Technical Reports Server (NTRS)

    Edelstein, F.

    1974-01-01

    Heat pipe manufacturing methods are examined with the goal of establishing cost effective procedures that will ultimately result in cheaper more reliable heat pipes. Those methods which are commonly used by all heat pipe manufacturers have been considered, including: (1) envelope and wick cleaning, (2) end closure and welding, (3) mechanical verification, (4) evacuation and charging, (5) working fluid purity, and (6) charge tube pinch off. The study is limited to moderate temperature aluminum and stainless steel heat pipes with ammonia, Freon-21 and methanol working fluids. Review and evaluation of available manufacturers techniques and procedures together with the results of specific manufacturing oriented tests have yielded a set of recommended cost-effective specifications which can be used by all manufacturers.

  17. Heat Pipe Systems

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The heat pipe was developed to alternately cool and heat without using energy or any moving parts. It enables non-rotating spacecraft to maintain a constant temperature when the surface exposed to the Sun is excessively hot and the non Sun-facing side is very cold. Several organizations, such as Tropic-Kool Engineering Corporation, joined NASA in a subsequent program to refine and commercialize the technology. Heat pipes have been installed in fast food restaurants in areas where humid conditions cause materials to deteriorate quickly. Moisture removal was increased by 30 percent in a Clearwater, FL Burger King after heat pipes were installed. Relative humidity and power consumption were also reduced significantly. Similar results were recorded by Taco Bell, which now specifies heat pipe systems in new restaurants in the Southeast.

  18. Heat pipe development

    NASA Technical Reports Server (NTRS)

    Bienart, W. B.

    1973-01-01

    The objective of this program was to investigate analytically and experimentally the performance of heat pipes with composite wicks--specifically, those having pedestal arteries and screwthread circumferential grooves. An analytical model was developed to describe the effects of screwthreads and screen secondary wicks on the transport capability of the artery. The model describes the hydrodynamics of the circumferential flow in triangular grooves with azimuthally varying capillary menisci and liquid cross-sections. Normalized results were obtained which give the influence of evaporator heat flux on the axial heat transport capability of the arterial wick. In order to evaluate the priming behavior of composite wicks under actual load conditions, an 'inverted' glass heat pipe was designed and constructed. The results obtained from the analysis and from the tests with the glass heat pipe were applied to the OAO-C Level 5 heat pipe, and an improved correlation between predicted and measured evaporator and transport performance were obtained.

  19. Miniature pipe crawler tractor

    DOEpatents

    McKay, Mark D.; Anderson, Matthew O.; Ferrante, Todd A.; Willis, W. David

    2000-01-01

    A pipe crawler tractor may comprise a half tractor assembly having a first base drive wheel, a second base drive wheel, and a top drive wheel. The drive wheels are mounted in spaced-apart relation so that the top drive wheel is positioned between the first and second base drive wheels. The mounting arrangement is also such that the first and second base drive wheels contact the inside surface of the pipe at respective first and second positions and so that the top drive wheel contacts the inside surface of the pipe at a third position, the third position being substantially diametrically opposed to the first and second positions. A control system connected to the half tractor assembly controls the rotation of the first base wheel, the second base wheel, and the top drive wheel to move the half tractor assembly within the pipe.

  20. The pipes of pan.

    PubMed

    Chalif, David J

    2004-12-01

    The pipes of pan is the crowning achievement of Pablo Picasso's neoclassical period of the 1920s. This monumental canvas depicts a mythological Mediterranean scene in which two sculpted classical giants stare out, seemingly across the centuries, toward a distant and lost Arcadia. Picasso was influenced by Greco-Roman art during his travels in Italy, and his neoclassical works typically portray massive, immobile, and pensive figures. Pan and his pipes are taken directly from Greek mythological lore by Picasso and placed directly into 20th century art. He frequently turned to various mythological figures throughout his metamorphosing periods. The Pipes of Pan was also influenced by the painter's infatuation with the beautiful American expatriate Sara Murphy, and the finished masterpiece represents a revision of a previously conceived neoclassical work. The Pipes of Pan now hangs in the Musee Picasso in Paris.

  1. An electrohydrodynamic heat pipe

    NASA Technical Reports Server (NTRS)

    Jones, T. B.

    1972-01-01

    Dielectric liquid for transfer of heat provides liquid flow from the condenser section to the evaporator section in conventional heat pipes. Working fluid is guided or pumped by an array of wire electrodes connected to a high-voltage source.

  2. CORROSION OF BURIED PIPES

    DTIC Science & Technology

    in excellent condition. Extreme care was necessary during installation to prevent cuts or nicks in the tape. The black steel pipes protected by bituminous coating, cured gilsonite , and uncured gilsonite had deteriorated badly.

  3. Liquid Explosive in Pipes

    DTIC Science & Technology

    1994-01-01

    ETH - ethanolamine, ED - ethylenediamine, HMT - hexamethylenetetramine , MOR - morpholine. NM - nitromethane, PYR - pyridine, TETA...ror a detonable mixture in 16-mm ID pipe: diethylamine, diethylenetetramine, ethanolamine, ethylenediamine, hexamethylenetetramine , morpholine

  4. Pipe Penetrating Radar: a New Tool for the Assessment of Critical Infrastructure

    NASA Astrophysics Data System (ADS)

    Ekes, C.; Neducz, B.

    2012-04-01

    This paper describes the development of Pipe Penetrating Radar (PPR), the underground in-pipe application of GPR, a non-destructive testing method that can detect defects and cavities within and outside mainline diameter (>18 in / 450mm) non-metallic (concrete, PVC, HDPE, etc.) underground pipes. The method uses two or more high frequency GPR antennae carried by a robot into underground pipes. The radar data is transmitted to the surface via fibre optic cable and is recorded together with the output from CCTV (and optionally sonar and laser). Proprietary software analyzes the data and pinpoints defects or cavities within and outside the pipe. Thus the testing can identify existing pipe and pipe bedding symptoms that can be addressed to prevent catastrophic failure due to sinkhole development and can provide useful information about the remaining service life of the pipe. The key innovative aspect is the unique ability to map pipe wall thickness and deterioration including cracks and voids outside the pipe, enabling accurate predictability of needed intervention or the timing of replacement. This reliable non-destructive testing method significantly impacts subsurface infrastructure condition based asset management by supplying previously unattainable measurable conditions. Keywords: pipe penetrating radar (PPR), ground penetrating radar (GPR), pipe inspection, concrete deterioration, municipal engineering

  5. Cavitation flow through a rotating pipe

    NASA Astrophysics Data System (ADS)

    Szumowski, A.; Laake, A.; Meier, G. E. A.

    1986-07-01

    A one-dimensional cavitation flow (without Coriolis accelaration) in a rotating pipe was investigated with a view to cooling of gas turbine blades and compressors. This flow becomes unsteady and oscillates. Thereby, and unsteady cavitation domain is produced, separating the two partial water columns. At increasing rotation speed the oscillation frequency decreases and the extension of the cavitation domain increases. Above a critical rotation speed the water column is pressed out of the pipe, and the cavitation domain disappears. The flow computation was performed using the Runge-Kutta method for an incompressible model, and the characteristics method for a compressible model. The results of the calculations are supported by experimental results.

  6. Silicon Heat Pipe Array

    NASA Technical Reports Server (NTRS)

    Yee, Karl Y.; Ganapathi, Gani B.; Sunada, Eric T.; Bae, Youngsam; Miller, Jennifer R.; Beinsford, Daniel F.

    2013-01-01

    Improved methods of heat dissipation are required for modern, high-power density electronic systems. As increased functionality is progressively compacted into decreasing volumes, this need will be exacerbated. High-performance chip power is predicted to increase monotonically and rapidly with time. Systems utilizing these chips are currently reliant upon decades of old cooling technology. Heat pipes offer a solution to this problem. Heat pipes are passive, self-contained, two-phase heat dissipation devices. Heat conducted into the device through a wick structure converts the working fluid into a vapor, which then releases the heat via condensation after being transported away from the heat source. Heat pipes have high thermal conductivities, are inexpensive, and have been utilized in previous space missions. However, the cylindrical geometry of commercial heat pipes is a poor fit to the planar geometries of microelectronic assemblies, the copper that commercial heat pipes are typically constructed of is a poor CTE (coefficient of thermal expansion) match to the semiconductor die utilized in these assemblies, and the functionality and reliability of heat pipes in general is strongly dependent on the orientation of the assembly with respect to the gravity vector. What is needed is a planar, semiconductor-based heat pipe array that can be used for cooling of generic MCM (multichip module) assemblies that can also function in all orientations. Such a structure would not only have applications in the cooling of space electronics, but would have commercial applications as well (e.g. cooling of microprocessors and high-power laser diodes). This technology is an improvement over existing heat pipe designs due to the finer porosity of the wick, which enhances capillary pumping pressure, resulting in greater effective thermal conductivity and performance in any orientation with respect to the gravity vector. In addition, it is constructed of silicon, and thus is better

  7. The Monster Sound Pipe

    ERIC Educational Resources Information Center

    Ruiz, Michael J.; Perkins, James

    2017-01-01

    Producing a deep bass tone by striking a large 3 m (10 ft) flexible corrugated drainage pipe immediately grabs student attention. The fundamental pitch of the corrugated tube is found to be a semitone lower than a non-corrugated smooth pipe of the same length. A video (https://youtu.be/FU7a9d7N60Y) of the demonstration is included, which…

  8. Freezable heat pipe

    DOEpatents

    Ernst, Donald M.; Sanzi, James L.

    1981-02-03

    A heat pipe whose fluid can be repeatedly frozen and thawed without damage to the casing. An additional part is added to a conventional heat pipe. This addition is a simple porous structure, such as a cylinder, self-supporting and free standing, which is dimensioned with its diameter not spanning the inside transverse dimension of the casing, and with its length surpassing the depth of maximum liquid.

  9. ASME code and ratcheting in piping components. Final technical report

    SciTech Connect

    Hassan, T.; Matzen, V.C.

    1999-05-14

    The main objective of this research is to develop an analysis program which can accurately simulate ratcheting in piping components subjected to seismic or other cyclic loads. Ratcheting is defined as the accumulation of deformation in structures and materials with cycles. This phenomenon has been demonstrated to cause failure to piping components (known as ratcheting-fatigue failure) and is yet to be understood clearly. The design and analysis methods in the ASME Boiler and Pressure Vessel Code for ratcheting of piping components are not well accepted by the practicing engineering community. This research project attempts to understand the ratcheting-fatigue failure mechanisms and improve analysis methods for ratcheting predictions. In the first step a state-of-the-art testing facility is developed for quasi-static cyclic and seismic testing of straight and elbow piping components. A systematic testing program to study ratcheting is developed. Some tests have already been performed an d the rest will be completed by summer'99. Significant progress has been made in the area of constitutive modeling. A number of sophisticated constitutive models have been evaluated in terms of their simulations for a broad class of ratcheting responses. From the knowledge gained from this evaluation study two improved models are developed. These models are demonstrated to have promise in simulating ratcheting responses in piping components. Hence, implementation of these improved models in widely used finite element programs, ANSYS and/or ABAQUS, is in progress. Upon achieving improved finite element programs for simulation of ratcheting, the ASME Code provisions for ratcheting of piping components will be reviewed and more rational methods will be suggested. Also, simplified analysis methods will be developed for operability studies of piping components and systems. Some of the future works will be performed under the auspices of the Center for Nuclear Power Plant Structures

  10. Increasing the volumetric efficiency of Diesel engines by intake pipes

    NASA Technical Reports Server (NTRS)

    List, Hans

    1933-01-01

    Development of a method for calculating the volumetric efficiency of piston engines with intake pipes. Application of this method to the scavenging pumps of two-stroke-cycle engines with crankcase scavenging and to four-stroke-cycle engines. The utility of the method is demonstrated by volumetric-efficiency tests of the two-stroke-cycle engines with crankcase scavenging. Its practical application to the calculation of intake pipes is illustrated by example.

  11. Moderated heat pipe thermionic reactor (MOHTR) module development and test

    NASA Astrophysics Data System (ADS)

    Merrigan, Michael A.; Trujillo, Vincent L.

    1992-01-01

    The Moderated Heat Pipe Thermionic Reactor (MOHTR) thermionic space reactor design combines the low risk technology associated with the Thermionic Fuel Element (TFE) Verification Program with the high reliability heat transfer capability of liquid metal heat pipe technology. The resulting design concept, capable of implementation over the power range of 10 to 100 kWe, offers efficiency and reliability with reduced risk of single point failures. The union of TFE and heat pipe technology is achieved by imbedding TFEs and heat pipes in a beryllium matrix to which they are thermally coupled by brazing or by liquid metal (NaK or Na) bonding. The reactor employs an array of TFE modules, each comprising a TFE, a zirconium hydride (ZrH) cylinder for neutron moderation, and heat pipes for transport of heat from the collector surface of the TFE to the waste heat radiator. An advantage of the design is the low temperature drop from the collector surface to the radiating surface. This is a result of the elimination of electrical insulation from the heat transport path through electrical isolation of the modules. The module used in this study consisted of a beryllium core, and electrical cartridge heater simulating the TFE, and three heat pipes to dissipate the waste heat. The investigation was focused on the thermal performance of the assembly, including evaluation of the sodium and braze bonding options for minimizing the thermal resistance between the elements, the temperature distribution in the beryllium matrix, and the heat pipe performance. Continuing subjects of the investigation include performance of the heat pipes through start-up transients, during normal operation, and in a single heat pipe failure mode. Secondary objectives of the investigation include correlation of analytic models for the thermionic element and module including the effects of gap thermal conductances at the modules electrically insulated surfaces.

  12. Depriming of arterial heat pipes: An investigation of CTS thermal excursions

    NASA Technical Reports Server (NTRS)

    Antoniuk, D.; Edwards, D. K.

    1980-01-01

    Four thermal excursions of the Transmitter Experiment Package (TEP) were the result of the depriming of the arteries in all three heat pipes in the Variable Conductance Heat Pipe System which cooled the TEP. The determined cause of the depriming of the heat pipes was the formation of bubbles of the nitrogen/helium control gas mixture in the arteries during the thaw portion of a freeze/thaw cycle of the inactive region of the condenser section of the heat pipe. Conditions such as suction freezeout or heat pipe turn-on, which moved these bubbles into the active region of the heat pipe, contributed to the depriming mechanism. Methods for precluding, or reducing the probability of, this type of failure mechanism in future applications of arterial heat pipes are included.

  13. Heat pipe dynamic behavior

    NASA Technical Reports Server (NTRS)

    Issacci, F.; Roche, G. L.; Klein, D. B.; Catton, I.

    1988-01-01

    The vapor flow in a heat pipe was mathematically modeled and the equations governing the transient behavior of the core were solved numerically. The modeled vapor flow is transient, axisymmetric (or two-dimensional) compressible viscous flow in a closed chamber. The two methods of solution are described. The more promising method failed (a mixed Galerkin finite difference method) whereas a more common finite difference method was successful. Preliminary results are presented showing that multi-dimensional flows need to be treated. A model of the liquid phase of a high temperature heat pipe was developed. The model is intended to be coupled to a vapor phase model for the complete solution of the heat pipe problem. The mathematical equations are formulated consistent with physical processes while allowing a computationally efficient solution. The model simulates time dependent characteristics of concern to the liquid phase including input phase change, output heat fluxes, liquid temperatures, container temperatures, liquid velocities, and liquid pressure. Preliminary results were obtained for two heat pipe startup cases. The heat pipe studied used lithium as the working fluid and an annular wick configuration. Recommendations for implementation based on the results obtained are presented. Experimental studies were initiated using a rectangular heat pipe. Both twin beam laser holography and laser Doppler anemometry were investigated. Preliminary experiments were completed and results are reported.

  14. Implementation of Seismic Stops in Piping Systems

    SciTech Connect

    Bezler, P.; Simos, N.; Wang, Y.K.

    1993-02-01

    Commonwealth Edison has submitted a request to NRC to replace the snubbers in the Reactor Coolant Bypass Line of Byron Station-Unit 2 with gapped pipe supports. The specific supports intended for use are commercial units designated ''Seismic Stops'' manufactured by Robert L. Cloud Associates, Inc. (RLCA). These devices have the physical appearance of snubbers and are essentially spring supports incorporating clearance gaps sized for the Byron Station application. Although the devices have a nonlinear stiffness characteristic, their design adequacy is demonstrated through the use of a proprietary linear elastic piping analysis code ''GAPPIPE'' developed by RLCA. The code essentially has all the capabilities of a conventional piping analysis code while including an equivalent linearization technique to process the nonlinear spring elements. Brookhaven National Laboratory (BNL) has assisted the NRC staff in its evaluation of the RLCA implementation of the equivalent Linearization technique and the GAPPIPE code. Towards this end, BNL performed a detailed review of the theoretical basis for the method, an independent evaluation of the Byron piping using the nonlinear time history capability of the ANSYS computer code and by result comparisons to the RLCA developed results, an assessment of the adequacy of the response estimates developed with GAPPIPE. Associated studies included efforts to verify the ANSYS analysis results and the development of bounding calculations for the Byron Piping using linear response spectrum methods.

  15. IMPLEMENTATION OF SEISMIC STOPS IN PIPING SYSTEMS.

    SciTech Connect

    BEZLER,P.

    1993-02-01

    Commonwealth Edison has submitted a request to NRC to replace the snubbers in the Reactor Coolant Bypass Line of Byron Station -Unit 2 with gapped pipe supports. The specific supports intended for use are commercial units designated ''Seismic Stops'' manufactured by Robert L. Cloud Associates, Inc. (RLCA). These devices have the physical appearance of snubbers and are essentially spring supports incorporating clearance gaps sized for the Byron Station application. Although the devices have a nonlinear stiffness characteristic, their design adequacy is demonstrated through the use of a proprietary linear elastic piping analysis code ''GAPPIPE'' developed by RLCA. The code essentially has all the capabilities of a conventional piping analysis code while including an equivalent linearization technique to process the nonlinear spring elements. Brookhaven National Laboratory (BNL) has assisted the NRC staff in its evaluation of the RLCA implementation of the equivalent linearization technique and the GAPPIPE code. Towards this end, BNL performed a detailed review of the theoretical basis for the method, an independent evaluation of the Byron piping using the nonlinear time history capability of the ANSYS computer code and by result comparisons to the RLCA developed results, an assessment of the adequacy of the response estimates developed with GAPPIPE. Associated studies included efforts to verify the ANSYS analysis results and the development of bounding calculations for the Byron Piping using linear response spectrum methods.

  16. Heat Pipe Integrated Microsystems

    SciTech Connect

    Gass, K.; Robertson, P.J.; Shul, R.; Tigges, C.

    1999-03-30

    The trend in commercial electronics packaging to deliver ever smaller component packaging has enabled the development of new highly integrated modules meeting the demands of the next generation nano satellites. At under ten kilograms, these nano satellites will require both a greater density electronics and a melding of satellite structure and function. Better techniques must be developed to remove the subsequent heat generated by the active components required to-meet future computing requirements. Integration of commercially available electronics must be achieved without the increased costs normally associated with current generation multi chip modules. In this paper we present a method of component integration that uses silicon heat pipe technology and advanced flexible laminate circuit board technology to achieve thermal control and satellite structure. The' electronics/heat pipe stack then becomes an integral component of the spacecraft structure. Thermal management on satellites has always been a problem. The shrinking size of electronics and voltage requirements and the accompanying reduction in power dissipation has helped the situation somewhat. Nevertheless, the demands for increased onboard processing power have resulted in an ever increasing power density within the satellite body. With the introduction of nano satellites, small satellites under ten kilograms and under 1000 cubic inches, the area available on which to place hot components for proper heat dissipation has dwindled dramatically. The resulting satellite has become nearly a solid mass of electronics with nowhere to dissipate heat to space. The silicon heat pipe is attached to an aluminum frame using a thermally conductive epoxy or solder preform. The frame serves three purposes. First, the aluminum frame provides a heat conduction path from the edge of the heat pipe to radiators on the surface of the satellite. Secondly, it serves as an attachment point for extended structures attached to

  17. The evaluation of moisture damage for CFRC pipes in conjunction with acoustic emission

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Su, Yu-Min; Liu, Yanjun; Tia, Mang

    2014-03-01

    The objective of this study was to evaluate the in-situ serviceability of cellulose fiber reinforced concrete (CFRC) pipes using Acoustic Emission (AE). Three-edge-bearing test was conducted on CFRC pipes in the laboratory in accordance with ASTM C497-05. Pipes were saturated in water for various periods of time to simulate the practical field situations of CFRC pipes with different service life exposed to moisture effects. AE sensors and LVDT were installed on pipes detect the damage phases during loading. Both monotonic and cyclic loading modes were conducted on the CFRC pipes. Results showed that the CFRC pipes generally exhibited the nonlinear load-displacement behavior before failure, yet the level of ductility was reduced with longer exposure to moisture condition. AE data were evaluated through two feature signals, that is, intensity analysis and calm ratio analysis. Results showed that AE can detect the onset of damage and the ultimate failure of CFRC pipes. Additionally, the analysis on CFRC pipes subjected to various moisture effects showed different features of AE results. It is found that intensity analysis can distinguish different periods of exposure to moisture and levels of ductility, which make it feasible to monitor the health of CFRC pipes under moisture effects.

  18. An Overview of Long Duration Sodium Heat Pipe Tests

    NASA Technical Reports Server (NTRS)

    Rosenfeld, John H.; Ernst, Donald M.; Lindemuth, James E.; Sanzi, James L.; Geng, Steven M.; Zuo, Jon

    2004-01-01

    High temperature heat pipes are being evaluated for use in energy conversion applications such as fuel cells, gas turbine re-combustors, and Stirling cycle heat sources; with the resurgence of space nuclear power, additional applications include reactor heat removal elements and radiator elements. Long operating life and reliable performance are critical requirements for these applications. Accordingly long-term materials compatibility is being evaluated through the use of high temperature life test heat pipes. Thermacore International, Inc., has carried out several sodium heat pipe life tests to establish long term operating reliability. Four sodium heat pipes have recently demonstrated favorable materials compatibility and heat transport characteristics at high operating temperatures in air over long time periods. A 3l6L stainless steel heat pipe with a sintered porous nickel wick structure and an integral brazed cartridge heater has successfully operated at 650 to 700 C for over 115,000 hours without signs of failure. A second 3l6L stainless steel heat pipe with a specially-designed Inconel 60 I rupture disk and a sintered nickel powder wick has demonstrated over 83,000 hours at 600 to 650 C with similar success. A representative one-tenth segment Stirling Space Power Converter heat pipe with an Inconel 718 envelope and a stainless steel screen wick has operated for over 41 ,000 hours at nearly 700 0c. A hybrid (i.e. gas-fired and solar) heat pipe with a Haynes 230 envelope and a sintered porous nickel wick structure was operated for about 20,000 hours at nearly 700 C without signs of degradation. These life test results collectively have demonstrated the potential for high temperature heat pipes to serve as reliable energy conversion system components for power applications that require long operating lifetime with high reliability, Detailed design specifications, operating hi story, and test results are described for each of these sodium heat pipes. Lessons

  19. An Overview of Long Duration Sodium Heat Pipe Tests

    NASA Astrophysics Data System (ADS)

    Rosenfeld, John H.; Ernst, Donald M.; Lindemuth, James E.; Sanzi, James L.; Geng, Steven M.; Zuo, Jon

    2004-02-01

    High temperature heat pipes are being evaluated for use in energy conversion applications such as fuel cells, gas turbine re-combustors, and Stirling cycle heat sources; with the resurgence of space nuclear power, additional applications include reactor heat removal elements and radiator elements. Long operating life and reliable performance are critical requirements for these applications. Accordingly long-term materials compatibility is being evaluated through the use of high temperature life test heat pipes. Thermacore, Inc. has carried out several sodium heat pipe life tests to establish long term operating reliability. Four sodium heat pipes have recently demonstrated favorable materials compatibility and heat transport characteristics at high operating temperatures in air over long time periods. A 316L stainless steel heat pipe with a sintered porous nickel wick structure and an integral brazed cartridge heater has successfully operated at 650C to 700C for over 115,000 hours without signs of failure. A second 316L stainless steel heat pipe with a specially-designed Inconel 601 rupture disk and a sintered nickel powder wick has demonstrated over 83,000 hours at 600C to 650C with similar success. A representative one-tenth segment Stirling Space Power Converter heat pipe with an Inconel 718 envelope and a stainless steel screen wick has operated for over 41,000 hours at nearly 700C. A hybrid (i.e. gas-fired and solar) heat pipe with a Haynes 230 envelope and a sintered porous nickel wick structure was operated for about 20,000 hours at nearly 700C without signs of degradation. These life test results collectively have demonstrated the potential for high temperature heat pipes to serve as reliable energy conversion system components for power applications that require long operating lifetime with high reliability. Detailed design specifications, operating history, and test results are described for each of these sodium heat pipes. Lessons learned and future life

  20. A Complete Piping Analysis With Thermal Stratification Loads

    SciTech Connect

    Milton Dong; Hong Ming Lee; Chii Chern

    2002-07-01

    The U. S. Nuclear Regulatory Commission (USNRC) had issued Bulletins 88-08, 88-11, 89-90, and 93-38 to address the concerns and problems due to thermal stratification loading during the life span of normal plant operation. The thermal stratification condition typically will cause pipe to bow in on a long horizontal segment. These conditions have not been commonly considered in piping design. However, the additional thermal cyclic stresses and loads due to these conditions could lead to the fatigue damage of the piping components and the failures of pipe supports. Analyzing the effects of thermal stratification loads can be very cumbersome if it is not a built-in functionality of the analysis program. Thus in response to the recent increase in such cases we have incorporated this feature in our piping stress computer program. A stress engineer can now define the thermal stratification conditions easily and the program will compute the pipe stresses and pipe support loads automatically as one of the load cases. The program then combines the thermal stratification load cases with other load cases as required in accordance with the load histogram to determine the cumulative fatigue damage of the piping system. The thermal cyclic stresses are evaluated in accordance with the design rules of Nuclear Class 1 piping components provided in NB-3650 of ASME section III Code. This paper presents the method, modeling and validation for implementing the functionality of analyzing thermal stratification loads in a computer program, as well as an application on an actual piping system as an illustration. (authors)

  1. OTEC cold water pipe design for problems caused by vortex-excited oscillations

    SciTech Connect

    Griffin, O. M.

    1980-03-14

    Vortex-excited oscillations of marine structures result in reduced fatigue life, large hydrodynamic forces and induced stresses, and sometimes lead to structural damage and to diestructive failures. The cold water pipe of an OTEC plant is nominally a bluff, flexible cylinder with a large aspect ratio (L/D = length/diameter), and is likely to be susceptible to resonant vortex-excited oscillations. The objective of this report is to survey recent results pertaining to the vortex-excited oscillations of structures in general and to consider the application of these findings to the design of the OTEC cold water pipe. Practical design calculations are given as examples throughout the various sections of the report. This report is limited in scope to the problems of vortex shedding from bluff, flexible structures in steady currents and the resulting vortex-excited oscillations. The effects of flow non-uniformities, surface roughness of the cylinder, and inclination to the incident flow are considered in addition to the case of a smooth cyliner in a uniform stream. Emphasis is placed upon design procedures, hydrodynamic coefficients applicable in practice, and the specification of structural response parameters relevant to the OTEC cold water pipe. There are important problems associated with in shedding of vortices from cylinders in waves and from the combined action of waves and currents, but these complex fluid/structure interactions are not considered in this report.

  2. Internal erosion during soil pipe flow: Role in gully erosion and hillslope instability

    USDA-ARS?s Scientific Manuscript database

    Many field observations have lead to speculation on the role of piping in embankment failures, landslides, and gully erosion. However, there has not been a consensus on the subsurface flow and erosion processes involved and inconsistent use of terms have exasperated the problem. One such piping proc...

  3. Fracture mechanics models developed for piping reliability assessment in light water reactors: piping reliability project

    SciTech Connect

    Harris, D.O.; Lim, E.Y.; Dedhia, D.D.; Woo, H.H.; Chou, C.K.

    1982-06-01

    The efforts concentrated on modifications of the stratified Monte Carlo code called PRAISE (Piping Reliability Analysis Including Seismic Events) to make it more widely applicable to probabilistic fracture mechanics analysis of nuclear reactor piping. Pipe failures are considered to occur as the result of crack-like defects introduced during fabrication, that escape detection during inspections. The code modifications allow the following factors in addition to those considered in earlier work to be treated: other materials, failure criteria and subcritical crack growth characteristic; welding residual and vibratory stresses; and longitudinal welds (the original version considered only circumferential welds). The fracture mechanics background for the code modifications is included, and details of the modifications themselves provided. Additionally, an updated version of the PRAISE user's manual is included. The revised code, known as PRAISE-B was then applied to a variety of piping problems, including various size lines subject to stress corrosion cracking and vibratory stresses. Analyses including residual stresses and longitudinal welds were also performed.

  4. Monitoring pipe line stress due to ground displacement

    SciTech Connect

    Greenwood, J.H. Jr.

    1986-04-01

    Northwest Pipeline Corp. has a large-diameter natural gas pipe line system from Ignacio, Colo., to Sumas, Wash. At Douglas Pass in Colorado, large landslides required several sections of the line to be relocated outside the slide areas: 4,400 ft of new line in April 1962 and 3,200 ft in March 1963. No serious disruptions occurred for the next 16 years. Then in July 1979, some 1,200 ft had to be relocated. From 1980 to date, many landslides in the Douglas Pass area have caused new deformations, with the springs of 1983 and 1984 being the worst years. In 1980, Northwest Pipeline began engineering and geotechnical studies of the landslide problems. These led to instrumentation and pipe monitoring which indicated that pipe failure can be predicted and prevented if important slope deformations or increases in pipe stresses are detected early enough to implement some mitigating measures. Excavation of the pipe to relieve the stresses was used in most cases. The method was so successful that no pipe failure occurred in 1984 within instrumented sections, in spite of the exceptionally bad climatic conditions experienced.

  5. Nonlinear vibration behaviors of casing pipe in the deep water

    NASA Astrophysics Data System (ADS)

    Tang, You-Gang; Zhang, Su-Xia; Yi, Cong

    2006-10-01

    The vortex-induced nonlinear vibration of casing pipes in the deep water was investigated considering the loads of current and combined wave-current. The vortex-induced vibration equation of a casing pipe was set up with considering the beam mode and Morison's nonlinear fluid loads as well as the vortex-excited loads. The approach of calculating vortex-excited nonlinear vibration by Galerkin's method was proposed. The natural vibration frequencies and modes were obtained, and the response including primary resonance induced by current and the composite resonance under combined wave-current for the 170 m long casing pipe in the 160 m depth of water were investigated. The results show that the dynamics response of casing pipe obviously increases, and the complicated response behaviors of casing pipe are described under combined wave-current.

  6. Response margins of the dynamic analysis of piping systems

    SciTech Connect

    Johnson, J.J.; Benda, B.J.; Chuang, T.Y.; Smith, P.D.

    1984-04-01

    This report is organized as follows: Section 2 describes the three piping systems of the Zion nuclear power plant which formed the basis of the present study. The auxiliary feedwater (AFW) piping from steam generator to containment, the residual heat removal (RHR) and safety injection piping in the auxiliary building, and the reactor coolant loops (RCL) including a portion of the branch lines were analyzed. Section 3 describes the analysis methods and the analyses performed. Section 4 presents the numerical results; the principal results presented as comparisons of response calculated by best estimate time history analysis methods vs. the SRP response spectrum technique. Section 5 draws conclusions from the results. Appendix A contains a brief description of the mathematical models that defined the structures containing the three piping systems. Response from these models provided input to the piping models. Appendix B provides a detailed derivation of the pseudostatic mode approach to the multisupport time history analysis method used in this study.

  7. A risk-based approach to sanitary sewer pipe asset management.

    PubMed

    Baah, Kelly; Dubey, Brajesh; Harvey, Richard; McBean, Edward

    2015-02-01

    Wastewater collection systems are an important component of proper management of wastewater to prevent environmental and human health implications from mismanagement of anthropogenic waste. Due to aging and inadequate asset management practices, the wastewater collection assets of many cities around the globe are in a state of rapid decline and in need of urgent attention. Risk management is a tool which can help prioritize resources to better manage and rehabilitate wastewater collection systems. In this study, a risk matrix and a weighted sum multi-criteria decision-matrix are used to assess the consequence and risk of sewer pipe failure for a mid-sized city, using ArcGIS. The methodology shows that six percent of the uninspected sewer pipe assets of the case study have a high consequence of failure while four percent of the assets have a high risk of failure and hence provide priorities for inspection. A map incorporating risk of sewer pipe failure and consequence is developed to facilitate future planning, rehabilitation and maintenance programs. The consequence of failure assessment also includes a novel failure impact factor which captures the effect of structurally defective stormwater pipes on the failure assessment. The methodology recommended in this study can serve as a basis for future planning and decision making and has the potential to be universally applied by municipal sewer pipe asset managers globally to effectively manage the sanitary sewer pipe infrastructure within their jurisdiction. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Heart Failure

    MedlinePlus

    ... version of this page please turn Javascript on. Heart Failure What is Heart Failure? In heart failure, the heart cannot pump enough ... failure often experience tiredness and shortness of breath. Heart Failure is Serious Heart failure is a serious and ...

  9. Loop heat pipe radiator

    SciTech Connect

    Sarraf, D.B.; Gernert, N.J.

    1996-03-01

    This paper describes the design and testing of a Loop Heat Pipe Radiator (LHPR) which was developed as an alternative to state-of-the-art axially-grooved heat pipes for space-based heat rejection which would be usable with tubing made of aluminum foil covered with a carbon-epoxy composite. The LHPR had an aluminum envelope and a polymer wick, and used ammonia as a working fluid. It was 4 meters long with a mass of 1.4 kg. The LHPR transported 500 watts at a 2.3 meter adverse inclination and 1500 watts when horizontal. This non-optimized LHPR had a 3000 watt-meter capability, which is four times greater than an axially-grooved heat pipe of similar power-handling capability and mass. In addition to a higher power handling capability, the LHPR has a much higher capillary margin than axially-grooved pipes. That high capillary margin simplifies ground testing in a 1-g environment by reducing the need for the careful levelling and vibration reduction required by axially-grooved pipes. {copyright} {ital 1996 American Institute of Physics.}

  10. Remotely operated pipe connector

    DOEpatents

    Josefiak, Leonard J.; Cramer, Charles E.

    1988-01-01

    An apparatus for remotely assembling and disassembling a Graylock type coctor between a pipe and a closure for the pipe includes a base and a receptacle on the base for the closure. The pipe is moved into position vertically above the closure by a suitable positioning device such that the flange on the pipe is immediately adjacent and concentric with the flange on the closure. A moving device then moves two semicircular collars from a position free of the closure to a position such that the interior cam groove of each collar contacts the two flanges. Finally, a tensioning device automatically allows remote tightening and loosening of a nut and bolt assembly on each side of the collar to cause a seal ring located between the flanges to be compressed and to seal the closure. Release of the pipe and the connector is accomplished in the reverse order. Preferably, the nut and bolt assembly includes an elongate shaft portion on which a removable sleeve is located.

  11. Wedgethread pipe connection

    DOEpatents

    Watts, John D.

    2003-06-17

    Several embodiments of a wedgethread pipe connection are disclosed that have improved makeup, sealing, and non-loosening characteristics. In one embodiment, an open wedgethread is disclosed that has an included angle measured in the gap between the stab flank and the load flank to be not less than zero, so as to prevent premature wedging between mating flanks before the position of full makeup is reached, as does occur between trapped wedgethreads wherein the included angle is less than zero. The invention may be used for pipe threads large or small, as a flush joint, with collars, screwed into plates or it may even be used to reversibly connect such as solid posts to base members where a wide makeup torque range is desired. This Open wedgethread, as opposed to trapped wedgethreads, provides a threaded pipe connection that: is more cost-effective; can seal high pressure gas; can provide selectively a connection strength as high as the pipe strength; assures easy makeup to the desired position of full makeup within a wide torque range; may have a torque strength as high as the pipe torque strength; is easier to manufacture; is easier to gage; and is less subject to handling damage.

  12. Design and cooling of BESIII beryllium beam pipe

    NASA Astrophysics Data System (ADS)

    Li, Xunfeng; Ji, Quan; Wang, Li; Zheng, Lifang

    2008-01-01

    The beryllium beam pipe was restructured according to the requirements of the upgraded BESIII (Beijing Spectrometer) experiment. SMO-1 (sparking machining oil no. 1) was selected as the coolant for the central beryllium beam pipe. The cooling gap width of the beryllium beam pipe was calculated, the influence of concentrated heat load on the wall temperature of the beryllium beam pipe was studied, and the optimal velocity of the SMO-1 in the gap was determined at the maximum heat load. A cooling system for the beam pipe was developed to control the outer wall temperature of the beam pipe. The cooling system is reported in this paper with regard to the following two aspects: the layouts and the automation. The performance of the cooling system was tested on the beam pipe model with trim size. The test results show that the design of the beryllium beam pipe is reasonable and that the cooling system achieves the BESIII experimental aim. The cooling system has already passed the acceptance test and has been installed in position. It will be put into practice for the BESIII experiment in 2008.

  13. Friction Stir Welding of Line-Pipe Steels

    SciTech Connect

    Sanderson, Samuel; Mahoney, Murray; Feng, Zhili; Larsen, Steve; Steel, Russel; Fleck, Dale

    2014-05-01

    Friction stir welding (FSW) offers both economic and technical advantages over conventional fusion welding practices for welding line-pipe. For offshore line-pipe construction, the economic savings has been shown to be considerable, approaching a calculated 25%. Offshore pipe is relatively small diameter but heavy wall compared to onshore pipe. One concern is the ability to achieve consistent full weld penetration in an on-site offshore FSW operation, e.g., on a lay-barge. In addition, depending on the size and morphology of the unwelded zone, lack of penetration at the weld root can be difficult if not impossible to detect by conventional NDE methods. Thus, an approach to assure consistent full penetration via process control is required for offshore line-pipe construction using FSW. For offshore construction, an internal structural mandrel can be used offering the opportunity to use a sacrificial anvil FSW approach. With this approach, a small volume of sacrificial material can be inserted into the structural anvil. The FSW tool penetrates into the sacrificial anvil, beyond the inner diameter of the pipe wall, thus assuring full penetration. The sacrificial material is subsequently removed from the pipe inner wall. In the work presented herein, FSW studies were completed on both 6 mm and 12 mm wall thickness line-pipe. Lastly, post-FSW evaluations including radiography, root-bend tests, and metallography demonstrated the merits of the sacrificial anvil approach to achieve consistent full penetration.

  14. Apparatus for moving a pipe inspection probe through piping

    DOEpatents

    Zollinger, W. Thor; Appel, D. Keith; Lewis, Gregory W.

    1995-01-01

    A method and apparatus for controllably moving devices for cleaning or inspection through piping systems, including piping systems with numerous piping bends therein, by using hydrostatic pressure of a working fluid introduced into the piping system. The apparatus comprises a reservoir or other source for supplying the working fluid to the piping system, a launch tube for admitting the device into the launcher and a reversible, positive displacement pump for controlling the direction and flow rate of the working fluid. The device introduced into the piping system moves with the flow of the working fluid through the piping system. The launcher attaches to the valved ends of a piping system so that fluids in the piping system can recirculate in a closed loop. The method comprises attaching the launcher to the piping system, supplying the launcher with working fluid, admitting the device into the launcher, pumping the working fluid in the direction and at the rate desired so that the device moves through the piping system for pipe cleaning or inspection, removing the device from the launcher, and collecting the working fluid contained in the launcher.

  15. Heat pipes and use of heat pipes in furnace exhaust

    DOEpatents

    Polcyn, Adam D.

    2010-12-28

    An array of a plurality of heat pipe are mounted in spaced relationship to one another with the hot end of the heat pipes in a heated environment, e.g. the exhaust flue of a furnace, and the cold end outside the furnace. Heat conversion equipment is connected to the cold end of the heat pipes.

  16. Apparatus for moving a pipe inspection probe through piping

    DOEpatents

    Zollinger, W.T.; Appel, D.K.; Lewis, G.W.

    1995-07-18

    A method and apparatus are disclosed for controllably moving devices for cleaning or inspection through piping systems, including piping systems with numerous piping bends therein, by using hydrostatic pressure of a working fluid introduced into the piping system. The apparatus comprises a reservoir or other source for supplying the working fluid to the piping system, a launch tube for admitting the device into the launcher and a reversible, positive displacement pump for controlling the direction and flow rate of the working fluid. The device introduced into the piping system moves with the flow of the working fluid through the piping system. The launcher attaches to the valved ends of a piping system so that fluids in the piping system can recirculate in a closed loop. The method comprises attaching the launcher to the piping system, supplying the launcher with working fluid, admitting the device into the launcher, pumping the working fluid in the direction and at the rate desired so that the device moves through the piping system for pipe cleaning or inspection, removing the device from the launcher, and collecting the working fluid contained in the launcher. 8 figs.

  17. Heat Pipe Technology

    NASA Astrophysics Data System (ADS)

    1981-01-01

    The heat pipe, a sealed chamber whose walls are lined with a "wick," a thin capillary network containing a working fluid in liquid form was developed for a heat distribution system for non-rotating satellites. Use of the heat pipe provides a continuous heat transfer mechanism. "Heat tubes" that improve temperature control in plastics manufacturing equipment incorporated the heat pipe technology. James M. Stewart, an independent consultant, patented the heat tubes he developed and granted a license to Kona Corporation. The Kona Nozzle for heaterless injection molding gets heat for its operation from an external source and has no internal heating bands, reducing machine maintenance and also eliminating electrical hazards associated with heater bands. The nozzles are used by Eastman Kodak, Bic Pen Corporation, Polaroid, Tupperware, Ford Motor Company, RCA, and Western Electric in the molding of their products.

  18. Composite drill pipe

    DOEpatents

    Leslie, James C [Fountain Valley, CA; Leslie, II, James C.; Heard, James [Huntington Beach, CA; Truong, Liem , Josephson; Marvin, Neubert [Huntington Beach, CA; Hans, [Anaheim, CA

    2008-12-02

    A composite pipe segment is formed to include tapered in wall thickness ends that are each defined by opposed frustoconical surfaces conformed for self centering receipt and intimate bonding contact within an annular space between corresponding surfaces of a coaxially nested set of metal end pieces. The distal peripheries of the nested end pieces are then welded to each other and the sandwiched and bonded portions are radially pinned. The composite segment may include imbedded conductive leads and the axial end portions of the end pieces are shaped to form a threaded joint with the next pipe assembly that includes a contact ring in one pipe assembly pierced by a pointed contact in the other to connect the corresponding leads across the joint.

  19. Apparatus for inspecting piping

    DOEpatents

    Zollingger, W.T.; Appel, D.K.; Park, L.R.

    1995-03-21

    An inspection rabbit is described for inspecting piping systems having severe bends therein. The rabbit consists of a flexible, modular body containing a miniaturized eddy current inspection probe, a self-contained power supply for proper operation of the rabbit, an outer surface that allows ease of movement through piping systems and means for transmitting data generated by the inspection device. The body is preferably made of flexible polyvinyl chloride (PVC) tubing or, alternatively, silicone rubber with a shrink wrapping of polytetrafluoroethylene (TEFLON{trademark}). The body is formed to contain the power supply, preferably a plurality of batteries, and a spool of communication wire that connects to a data processing computer external to the piping system. 6 figures.

  20. Heat-pipe Earth.

    PubMed

    Moore, William B; Webb, A Alexander G

    2013-09-26

    The heat transport and lithospheric dynamics of early Earth are currently explained by plate tectonic and vertical tectonic models, but these do not offer a global synthesis consistent with the geologic record. Here we use numerical simulations and comparison with the geologic record to explore a heat-pipe model in which volcanism dominates surface heat transport. These simulations indicate that a cold and thick lithosphere developed as a result of frequent volcanic eruptions that advected surface materials downwards. Declining heat sources over time led to an abrupt transition to plate tectonics. Consistent with model predictions, the geologic record shows rapid volcanic resurfacing, contractional deformation, a low geothermal gradient across the bulk of the lithosphere and a rapid decrease in heat-pipe volcanism after initiation of plate tectonics. The heat-pipe Earth model therefore offers a coherent geodynamic framework in which to explore the evolution of our planet before the onset of plate tectonics.

  1. Apparatus for inspecting piping

    DOEpatents

    Zollingger, W. Thor; Appel, D. Keith; Park, Larry R.

    1995-01-01

    An inspection rabbit for inspecting piping systems having severe bends therein. The rabbit consists of a flexible, modular body containing a miniaturized eddy current inspection probe, a self-contained power supply for proper operation of the rabbit, an outer surface that allows ease of movement through piping systems and means for transmitting data generated by the inspection device. The body is preferably made of flexible polyvinyl chloride (PVC) tubing or, alternatively, silicone rubber with a shrink wrapping of polytetrafluoroethylene (TEFLON.RTM.). The body is formed to contain the power supply, preferably a plurality of batteries, and a spool of communication wire that connects to a data processing computer external to the piping system.

  2. Heat Pipe Technology

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The heat pipe, a sealed chamber whose walls are lined with a "wick," a thin capillary network containing a working fluid in liquid form was developed for a heat distribution system for non-rotating satellites. Use of the heat pipe provides a continuous heat transfer mechanism. "Heat tubes" that improve temperature control in plastics manufacturing equipment incorporated the heat pipe technology. James M. Stewart, an independent consultant, patented the heat tubes he developed and granted a license to Kona Corporation. The Kona Nozzle for heaterless injection molding gets heat for its operation from an external source and has no internal heating bands, reducing machine maintenance and also eliminating electrical hazards associated with heater bands. The nozzles are used by Eastman Kodak, Bic Pen Corporation, Polaroid, Tupperware, Ford Motor Company, RCA, and Western Electric in the molding of their products.

  3. Heat pipe array heat exchanger

    DOEpatents

    Reimann, Robert C.

    1987-08-25

    A heat pipe arrangement for exchanging heat between two different temperature fluids. The heat pipe arrangement is in a ounterflow relationship to increase the efficiency of the coupling of the heat from a heat source to a heat sink.

  4. Superfluid Helium Heat Pipe

    NASA Astrophysics Data System (ADS)

    Gully, P.

    This paper reports on the development and the thermal tests of three superfluid helium heat pipes. Two of them are designed to provide a large transport capacity (4 mW at 1.7 K). They feature a copper braid located inside a 6 mm outer diameter stainless tube fitted with copper ends for mechanical anchoring. The other heat pipe has no copper braid and is designed to get much smaller heat transport capacity (0.5 mW) and to explore lower temperature (0.7 - 1 K). The copper braid and the tube wall is the support of the Rollin superfluid helium film in which the heat is transferred. The low filling pressure makes the technology very simple with the possibility to easily bend the tube. We present the design and discuss the thermal performance of the heat pipes tested in the 0.7 to 2.0 K temperature range. The long heat pipe (1.2 m with copper braid) and the short one (0.25 m with copper braid) have similar thermal performance in the range 0.7 - 2.0 K. At 1.7 K the long heat pipe, 120 g in weight, reaches a heat transfer capacity of 6.2 mW and a thermal conductance of 600 mW/K for 4 mW transferred power. Due to the pressure drop of the vapor flow and Kapitza thermal resistance, the conductance of the third heat pipe dramatically decreases when the temperature decreases. A 3.8 mW/K is obtained at 0.7 K for 0.5 mW transferred power.

  5. Seismic fragility test of a 6-inch diameter pipe system

    SciTech Connect

    Chen, W. P.; Onesto, A. T.; DeVita, V.

    1987-02-01

    This report contains the test results and assessments of seismic fragility tests performed on a 6-inch diameter piping system. The test was funded by the US Nuclear Regulatory Commission (NRC) and conducted by ETEC. The objective of the test was to investigate the ability of a representative nuclear piping system to withstand high level dynamic seismic and other loadings. Levels of loadings achieved during seismic testing were 20 to 30 times larger than normal elastic design evaluations to ASME Level D limits would permit. Based on failure data obtained during seismic and other dynamic testing, it was concluded that nuclear piping systems are inherently able to withstand much larger dynamic seismic loadings than permitted by current design practice criteria or predicted by the probabilistic risk assessment (PRA) methods and several proposed nonlinear methods of failure analysis.

  6. Heat transfer in pipes

    NASA Technical Reports Server (NTRS)

    Burbach, T.

    1985-01-01

    The heat transfer from hot water to a cold copper pipe in laminar and turbulent flow condition is determined. The mean flow through velocity in the pipe, relative test length and initial temperature in the vessel were varied extensively during tests. Measurements confirm Nusselt's theory for large test lengths in laminar range. A new equation is derived for heat transfer for large starting lengths which agrees satisfactorily with measurements for large starting lengths. Test results are compared with the new Prandtl equation for heat transfer and correlated well. Test material for 200- and to 400-diameter test length is represented at four different vessel temperatures.

  7. Heat Pipe With Interrupted Slot

    NASA Technical Reports Server (NTRS)

    Brown, Richard F.; Kosson, Robert L.; Edelstein, Fred

    1994-01-01

    Newer version of heat pipe slot interrupted by plug or, if heat pipe is cast, by bridge of heat-pipe material cast integrally across groove. Small barrier assists in priming heat pipe. Vapor and noncondensible gas still accumulates in liquid channel at evaporator before or during startup, but barrier keeps liquid out of small part of slot at bubble. Dry part of slot allows bubble to escape into vapor channel, making room for liquid to move in during startup.

  8. Neutron Imaging of Alkali Metal Heat Pipes

    NASA Astrophysics Data System (ADS)

    Kihm, K.; Kirchoff, E.; Golden, M.; Rosenfeld, J.; Rawal, S.; Pratt, D.; Swanson, A.; Bilheux, H.; Walker, L.; Voisin, S.; Hussey, D. S.; Jacobson, D. L.

    High-temperature heat pipes are two-phase, capillary driven heat transfer devices capable of passively providing high thermal fluxes. Such a device using a liquid-metal coolant can be used as a solution for successful thermal management on hypersonic flight vehicles. Imaging of the liquid-metal coolant inside will provide valuable information in characterizing the detailed heat and mass transport. Neutron imaging possesses an inherent advantage from the fact that neutrons penetrate the heat pipe metal walls with very little attenuation, but are significantly attenuated by the liquid metal contained inside. Using the BT-2 beam line at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland, preliminary efforts have been conducted on a nickel-sodium heat pipe. The contrast between the attenuated beam and the background is calculated to be approximately 3%. This low contrast requires sacrifice in spatial or temporal resolution so efforts have since been concentrated on lithium (Li) which has a substantially larger neutron attenuation cross section. Using the CG-1D beam line at the High Flux Isotope Reactor (HFIR) of Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, the first neutron images of high-temperature molybdenum (Mo)-Li heat pipes have been achieved. The relatively high neutron cross section of Li allows for the visualization of the Li working fluid inside the heat pipes. The evaporator region of a gravity assisted cylindrical heat pipe prototype 25 cm long was imaged from start-up to steady state operation up to approximately 900 °C. In each corner of the square bore inside, the capillary action raises the Li meniscus above the bulk Li pool in the evaporator region. As the operational temperature changes, the meniscus shapes and the bulk meniscus height also changes. Furthermore, a three-dimensional tomographic image is also reconstructed from the total of 128 projection images taken 1.4o apart in which the Li had

  9. Neutron imaging of alkali metal heat pipes

    SciTech Connect

    Kihm, Ken; Kirchoff, Eric; Golden, Matt; Rosenfeld, J.; Rawal, S.; Pratt, D.; Bilheux, Hassina Z; Walker, Lakeisha MH; Voisin, Sophie; Hussey, Dan

    2013-01-01

    High-temperature heat pipes are two-phase, capillary driven heat transfer devices capable of passively providing high thermal fluxes. Such a device using a liquid-metal coolant can be used as a solution for successful thermal management on hypersonic flight vehicles. Imaging of the liquid-metal coolant inside will provide valuable information in characterizing the detailed heat and mass transport. Neutron imaging possesses an inherent advantage from the fact that neutrons penetrate the heat pipe metal walls with very little attenuation, but are significantly attenuated by the liquid metal contained inside. Using the BT-2 beam line at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland, preliminary efforts have been conducted on a nickel-sodium heat pipe. The contrast between the attenuated beam and the background is calculated to be approximately 3%. This low contrast requires sacrifice in spatial or temporal resolution so efforts have since been concentrated on lithium (Li) which has a substantially larger neutron attenuation cross section. Using the CG-1D beam line at the High Flux Isotope Reactor (HFIR) of Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, the first neutron images of high-temperature molybdenum (Mo)-Li heat pipes have been achieved. The relatively high neutron cross section of Li allows for the visualization of the Li working fluid inside the heat pipes. The evaporator region of a gravity assisted cylindrical heat pipe prototype 25 cm long was imaged from start-up to steady state operation up to approximately 900 C. In each corner of the square bore inside, the capillary action raises the Li meniscus above the bulk Li pool in the evaporator region. As the operational temperature changes, the meniscus shapes and the bulk meniscus height also changes. Furthermore, a three-dimensional tomographic image is also reconstructed from the total of 128 projection images taken 1.4o apart in which the Li had

  10. Effect of explosion pressure on pipe collapse in chemical plants

    SciTech Connect

    Kurashiki, Tetsusei; Zako, Masaru

    1995-12-31

    Once a big earthquake attacks the chemical plant and tanks are broken, the disaster will extend due to the dangerous materials in tanks. In addition, the destructive explosion pressure leads to the collapse of pipes, structures and missiles from these broken pieces. Therefore, simulating the disasters in chemical plants is very important for the safety and the reliability evaluation. In this study, a computer program to analyze the behavior of pipe and chemical equipment under explosion pressure on a personal computer has been developed. The outline of the algorithm is as follows: (1) Three-dimensional pressure applied on pipes at the explosion is calculated. (2) The effect of interception of explosion pressure by oil dike is quantified. (3) Mechanical behavior of pipe is analyzed by FEM using beam element, and pipe collapse is evaluated from the result of FEM. (4) Cumulative damage caused by sequential explosion of tanks is calculated. As an example, the developed system was applied to practical plant model, and the damaged zone in the plant and the dangerous location of pipes after the explosion of a tank have been analyzed. As a result, it is revealed that the proposed computer program is very useful not only for safety and reliability evaluation but for the installation of pipes in chemical plants as well.

  11. Apparatus for handling well pipe

    SciTech Connect

    Boyadjieff, G.I.

    1988-08-23

    This patent describes a well pipe handling machine for use in a rig having a string of pipe extending vertically along an axis of a well, comprising: a movable support; pipe holding means carried by the support for movement therewith and adapted to hold a section of pipe in vertical condition; means for moving the support carrying the pipe holding means and a pipe section held thereby between a first position in which the pipe holding means hold the pipe section in vertical condition in alignment with the axis of the well and a second position in which the pipe holding means locate the pipe section in vertical condition at a storage location offset from the axis; a control station for holding an operator and which is carried by the support for movement therewith between the first and second positions of the support; a torque wrench for making or breaking a connection between a vertical pipe section and the pipe string and which is carried by the support at essentially the lower end of the control station and for movement with the support between the first and second positions thereof.

  12. Reusable high-temperature heat pipes and heat pipe panels

    NASA Technical Reports Server (NTRS)

    Camarda, Charles J. (Inventor); Ransone, Philip O. (Inventor)

    1989-01-01

    A reusable, durable heat pipe which is capable of operating at temperatures up to about 3000 F in an oxidizing environment and at temperatures above 3000 F in an inert or vacuum environment is produced by embedding a refractory metal pipe within a carbon-carbon composite structure. A reusable, durable heat pipe panel is made from an array of refractory-metal pipes spaced from each other. The reusable, durable, heat-pipe is employed to fabricate a hypersonic vehicle leading edge and nose cap.

  13. Computer Program For Variable-Conductance Heat Pipes

    NASA Technical Reports Server (NTRS)

    Antoniuk, D.

    1992-01-01

    VCHPDA provides accurate mathematical models of transient as well as steady-state performance of variable-conductance heat pipes over wide range of operating conditions. Applies to heat pipes with either cold, wicked or hot, nonwicked gas reservoirs and uses ideal-gas law and "flat-front" (negligible vapor diffusion) gas theory. Calculates length of gas-blocked region and temperature of vapor in active portion of heat pipe by solving set of nonlinear equations for conservation of energy and mass. Written in FORTRAN 77.

  14. Computer Program For Variable-Conductance Heat Pipes

    NASA Technical Reports Server (NTRS)

    Antoniuk, D.

    1992-01-01

    VCHPDA provides accurate mathematical models of transient as well as steady-state performance of variable-conductance heat pipes over wide range of operating conditions. Applies to heat pipes with either cold, wicked or hot, nonwicked gas reservoirs and uses ideal-gas law and "flat-front" (negligible vapor diffusion) gas theory. Calculates length of gas-blocked region and temperature of vapor in active portion of heat pipe by solving set of nonlinear equations for conservation of energy and mass. Written in FORTRAN 77.

  15. Bedload measurement with a set of vertical and horizontal pipe hydrophones in a mountainous stream

    NASA Astrophysics Data System (ADS)

    Tsutsumi, Daizo; Fujita, Masaharu; Nonaka, Michinobu

    2016-04-01

    The pipe hydrophone has been shown to be an effective means for monitoring bedload transport in mountainous streams. It is commonly installed perpendicular to the flow on a stable river bed such as a check dam. Acoustic pulses caused by bedload collisions on the pipe are detected by a microphone. However, bedload particles saltating over the pipe remain undetected. To overcome this disadvantage we have installed a horizontal as well as a vertical pipe hydrophone in the Ashiarai-dani supercritical flume located in the Hida mountain range, Japan. The vertical pipe was installed on the wall of the flume and the horizontal pipe was installed on the flume bed. The horizontal and vertical pipes respond acoustically; the acoustic energy derived from the horizontal pipe is larger than that for the vertical, but the number of pulses from the vertical pipe is more numerous than that monitored by the horizontal pipe at high amplitudes. We explain this as follows: the volumetric concentration of bedload decreases with increased height above the bed. Therefore, the acoustic response of the horizontal pipe is expected to be larger than that of the vertical pipe. However, at high amplitudes and high bedload discharges the pulses of the horizontal pipe are saturated but those of the vertical pipe are not saturated. We propose a ratio (Rhv) between pulses detected by these sensors, and applied this ratio in calibrating the contemporaneous pulses detected by a hydrophone located immediately upstream of a Reid-type bedload slot sampler. Indeed the Rhv-corrected pulses correlate well with the bedload discharge calculated from the sampler, thereby supporting our explanation. We conclude that bedload monitoring using concomitant vertical and horizontal pipe hydrophones can be used to calibrate centrally-located hydrophones, thereby representing bedload discharges more accurately than those based on a single pipe hydrophone.

  16. Corrosion in prestressed concrete: Pipes, piles, and decks

    SciTech Connect

    Szeliga, M.

    1995-12-31

    This is the first compilation or book focusing on prestressed concrete. It features 21 classic NACE papers on prestressed concrete piping, piles, bridge decks, and cathodic protection. It includes basic corrosion mechanisms of prestressed concrete structures with detailed case histories of corrosion failures and corrective measures.

  17. Recent evaluations of crack-opening-area in circumferentially cracked pipes

    SciTech Connect

    Rahman, S.; Brust, F.; Ghadiali, N.; Wilkowski, G.; Miura, N.

    1997-04-01

    Leak-before-break (LBB) analyses for circumferentially cracked pipes are currently being conducted in the nuclear industry to justify elimination of pipe whip restraints and jet shields which are present because of the expected dynamic effects from pipe rupture. The application of the LBB methodology frequently requires calculation of leak rates. The leak rates depend on the crack-opening area of the through-wall crack in the pipe. In addition to LBB analyses which assume a hypothetical flaw size, there is also interest in the integrity of actual leaking cracks corresponding to current leakage detection requirements in NRC Regulatory Guide 1.45, or for assessing temporary repair of Class 2 and 3 pipes that have leaks as are being evaluated in ASME Section XI. The objectives of this study were to review, evaluate, and refine current predictive models for performing crack-opening-area analyses of circumferentially cracked pipes. The results from twenty-five full-scale pipe fracture experiments, conducted in the Degraded Piping Program, the International Piping Integrity Research Group Program, and the Short Cracks in Piping and Piping Welds Program, were used to verify the analytical models. Standard statistical analyses were performed to assess used to verify the analytical models. Standard statistical analyses were performed to assess quantitatively the accuracy of the predictive models. The evaluation also involved finite element analyses for determining the crack-opening profile often needed to perform leak-rate calculations.

  18. Heat pipe design handbook, part 2. [digital computer code specifications

    NASA Technical Reports Server (NTRS)

    Skrabek, E. A.

    1972-01-01

    The utilization of a digital computer code for heat pipe analysis and design (HPAD) is described which calculates the steady state hydrodynamic heat transport capability of a heat pipe with a particular wick configuration, the working fluid being a function of wick cross-sectional area. Heat load, orientation, operating temperature, and heat pipe geometry are specified. Both one 'g' and zero 'g' environments are considered, and, at the user's option, the code will also perform a weight analysis and will calculate heat pipe temperature drops. The central porous slab, circumferential porous wick, arterial wick, annular wick, and axial rectangular grooves are the wick configurations which HPAD has the capability of analyzing. For Vol. 1, see N74-22569.

  19. Heat-pipe planets

    NASA Astrophysics Data System (ADS)

    Moore, William B.; Simon, Justin I.; Webb, A. Alexander G.

    2017-09-01

    Observations of the surfaces of all terrestrial bodies other than Earth reveal remarkable but unexplained similarities: endogenic resurfacing is dominated by plains-forming volcanism with few identifiable centers, magma compositions are highly magnesian (mafic to ultra-mafic), tectonic structures are dominantly contractional, and ancient topographic and gravity anomalies are preserved to the present. Here we show that cooling via volcanic heat pipes may explain these observations and provide a universal model of the way terrestrial bodies transition from a magma-ocean state into subsequent single-plate, stagnant-lid convection or plate tectonic phases. In the heat-pipe cooling mode, magma moves from a high melt-fraction asthenosphere through the lithosphere to erupt and cool at the surface via narrow channels. Despite high surface heat flow, the rapid volcanic resurfacing produces a thick, cold, and strong lithosphere which undergoes contractional strain forced by downward advection of the surface toward smaller radii. We hypothesize that heat-pipe cooling is the last significant endogenic resurfacing process experienced by most terrestrial bodies in the solar system, because subsequent stagnant-lid convection produces only weak tectonic deformation. Terrestrial exoplanets appreciably larger than Earth may remain in heat-pipe mode for much of the lifespan of a Sun-like star.

  20. Find optimum pipe size

    SciTech Connect

    Fastenakels, M.; Campana, H.

    1984-09-01

    For decades, chemical engineers have used various rules of thumb for selecting the size of pipe in continuousprocess plants. Often these methods result in sizes that are not the correct selection for the operating conditions. This causes the plant to be less efficient to operate or more costly to erect. The optimum size is controlled by one of three modes of selection: the least annual cost (energy external source), the pressure drop available or the velocity allowable (often is two-phase flow)./sup 3/ Pressure drop available applies when a pressure loss may be (or must be) absorbed by the pipe. The optimum size then becomes the smallest and the least expensive that permits the flow to take place with no undesirable side effects. Except for very special cases, this would not be used in conjunction with a pumped or compressed fluid. This mode requires at least an approximation of the length of the pipe and the quantity and nature of the fittings in the system before the selection can be made. It can also apply under some conditions to the suction piping for pumps or compressors, to the lines conducting steam to and from reciprocating pumps and to heating equipment.

  1. Heat pipe investigations

    NASA Technical Reports Server (NTRS)

    Marshburn, J. P.

    1973-01-01

    Techniques associated with thermal-vacuum and bench testing, along with flight testing of the OAO-C spacecraft heat pipes are outlined, to show that the processes used in heat transfer design and testing are adequate for good performance evaluations.

  2. Commercial high efficiency dehumidification systems using heat pipes

    SciTech Connect

    Not Available

    1993-09-01

    An improved heat pipe design using separately connected two-section one-way flow heat pipes with internal microgrooves instead of wicks is described. This design is now commercially available for use to increase the dehumidification capacity of air conditioning systems. The design also includes a method of introducing fresh air into buildings while recovering heat and controlling the humidity of the incoming air. Included are applications and case studies, load calculations and technical data, and installation, operation, and maintenance information.

  3. On the initial flaw sizes of uPVC pipe materials

    SciTech Connect

    Kim, H.S. . Dept. of Mechanical Engineering)

    1993-12-20

    It is well known that flaws in unplasticized poly(vinyl chloride) (uPVC) pipes are generated during processing. The flaws include inclusions, gas bubbles, and results from poor fusion between PVC grains and extrusion additives. uPVC pipes are often used for water reticulation, subjected to an alternating pressure superimposed on a mean pressure. uPVC pipe samples have been found to fail in fatigue from a small semicircular flaw on the inside bore of the pipe. In designing uPVC pipes against fatigue failure due to pressure variation, it is essential to determine the initial flaw size. Truss attempted to estimate the lifespan of uPVC pipes and showed that predictions and experimental data are in good agreement.

  4. Energy transfer mechanism and probability analysis of submarine pipe laterally impacted by dropped objects

    NASA Astrophysics Data System (ADS)

    Liang, Jing; Yu, Jian-xing; Yu, Yang; Lam, W.; Zhao, Yi-yu; Duan, Jing-hui

    2016-06-01

    Energy transfer ratio is the basic-factor affecting the level of pipe damage during the impact between dropped object and submarine pipe. For the purpose of studying energy transfer and damage mechanism of submarine pipe impacted by dropped objects, series of experiments are designed and carried out. The effective yield strength is deduced to make the quasi-static analysis more reliable, and the normal distribution of energy transfer ratio caused by lateral impact on pipes is presented by statistic analysis of experimental results based on the effective yield strength, which provides experimental and theoretical basis for the risk analysis of submarine pipe system impacted by dropped objects. Failure strains of pipe material are confirmed by comparing experimental results with finite element simulation. In addition, impact contact area and impact time are proved to be the major influence factors of energy transfer by sensitivity analysis of the finite element simulation.

  5. Specialist meeting on leak before break in reactor piping and vessels

    SciTech Connect

    Bartholome, G.; Bazant, E.; Wellein, R.

    1997-04-01

    A series of research projects sponsored by the Federal Minister for Education, Science, Research and Technology, Bonn are summarized and compared to utility, manufacturer, and vendor tests. The purpose of the evaluation was to experimentally verify Leak-before-Break behavior, confirm the postulation of fracture preclusion for piping (straight pipe, bends and branches), and quantify the safety margin against massive failure. The results are applicable to safety assessment of ferritic and austenitic piping in primary and secondary nuclear power plant circuits. Moreover, because of the wide range of the test parameters, they are also important for the design and assessment of piping in other technical plant. The test results provide justification for ruling out catastrophic fractures, even on pipes of dimensions corresponding to those of a main coolant pipe of a pressurized water reactor plant on the basis of a mechanical deterministic safety analysis in correspondence with the Basis Safety Concept (Principle of Fracture Exclusion).

  6. Helical buckling of pipes in extended reach and horizontal wells -- Part 2: Frictional drag analysis

    SciTech Connect

    Wu, J.; Juvkam-Wold, H.C. . Petroleum Engineering Dept.)

    1993-09-01

    This paper studies the frictional drag of helically buckled pipes (drillstring and tubing) in extended reach and horizontal wells to correctly predict the actual bit weight or packer load, in cases where helical buckling of pipes may have occurred. Helical buckling of pipes in such wells may occur, since large axial loads are often required. The differential equation of axial force balance with consideration of the axial friction for helically buckled pipes is resolved, and the solution shows that when the pipes are helically buckled, the frictional drag will become very large. The actual bit weight for drilling or packer load for well completion may therefore become much smaller than estimated under the unbuckled pipe conditions. The analytical solution is also shown to agree with the results from laboratory experiments, which simulate the real wellbore-pipe conditions. An example is provided to show the calculation procedure and the importance of the results.

  7. Investigation of bubbles in arterial heat pipes

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.

    1972-01-01

    The behavior of gas occlusions in arterial heat pipes has been studied experimentally and theoretically. Specifically, the gas-liquid system properties, solubility and diffusivity, have been measured from -50 to 100 C for helium and argon in ammonia, Freon-21 (CHC12F), and methanol. Properties values obtained were then used to experimentally test models for gas venting from a heat pipe artery under isothermal conditions (i.e., no-heat flow), although the models, as developed, are also applicable to heat pipes operated at power, with some minor modifications. Preliminary calculations indicated arterial bubbles in a stagnant pipe require from minutes to days to collapse and vent. It has been found experimentally that a gas bubble entrapped within an artery structure has a very long lifetime in many credible situations. This lifetime has an approximately inverse exponential dependence on temperature, and is generally considerably longer for helium than for argon. The models postulated for venting under static conditions were in general quantitative agreement with experimental data. Factors of primary importance in governing bubble stability are artery diameter, artery wall thickness, noncondensible gas partial pressure, and the property group (the Ostwald solubility coefficient multiplied by the gas/liquid diffusivity).

  8. Model changes improve compressor-station piping pressure-loss predictions

    SciTech Connect

    Meyer, T.R.

    1985-04-29

    This article explains steps taken to modify loss calculations to predict more accurately pressure losses in the station piping systems of Texas Gas. The article does not attempt to set any industry standards for determining pressure drop in station piping. Its purposes are to point out that problems exist in current methods used for calculating station piping pressure losses, to show that manufacturer estimates of pressure drop may not always reflect actual conditions, and to outline the procedure used by Texas Gas to model more accurately compressor station piping.

  9. Evaluation of fatigue crack behavior in electron beam irradiated polyethylene pipes

    NASA Astrophysics Data System (ADS)

    Pokharel, Pashupati; Jian, Wei; Choi, Sunwoong

    2016-09-01

    A cracked round bar (CRB) fatigue test was employed to determine the slow crack growth (SCG) behavior of samples from high density polyethylene (HDPE) pipes using PE4710 resin. The structure property relationships of fatigue failure of polyethylene CRB specimens which have undergone various degree of electron beam (EB) irradiation were investigated by observing fatigue failure strength and the corresponding fracture surface morphology. Tensile test of these HDPE specimens showed improvements in modulus and yield strength while the failure strain decreased with increasing EB irradiation. The CRB fatigue test of HDPE pipe showed remarkable effect of EB irradiation on number of cycles to failure. The slopes of the stress-cycles to failure curve were similar for 0-100 kGy; however, significantly higher slope was observed for 500 kGy EB irradiated pipe. Also, the cycle to fatigue failure was seen to decrease as with EB irradiation in the high stress range, ∆σ=(16 MPa to 10.8 MPa); however, 500 kGy EB irradiated samples showed longer cycles to failure than the un-irradiated specimens at the stress range below 9.9 MPa and the corresponding initial stress intensity factor (∆KI,0)=0.712 MPa m1/2. The fracture surface morphology indicated that the cross-linked network in 500 kGy EB irradiated PE pipe can endure low dynamic load more effectively than the parent pipe.

  10. Experimental Verification of Steel Pipe Collapse under Vacuum Pressure Conditions

    NASA Astrophysics Data System (ADS)

    Autrique, R.; Rodal, E.

    2016-11-01

    Steel pipes are used widely in hydroelectric systems and in pumping systems. Both systems are subject to hydraulic transient effects caused by changes in boundary conditions, such as sudden valve closures, pump failures, or accidents. Water column separation, and its associated vaporization pressure inside the pipe, can cause the collapse of thin walled steel pipes subject to atmospheric pressure, as happened during the well known Oigawa Power Plant accident in Japan, in 1950. The conditions under which thin walled pipes subject to external pressure can collapse have been studied mathematically since the second half of the XIX century, with classical authors Southwell and Von Mises obtaining definitive equations for long and short pipes in the second decade of the XX century, in which the fundamental variables are the diameter to thickness ratio D/t and the length to diameter ratio L/D. In this paper, the predicted critical D/t ratio for steel pipe collapse is verified experimentally, in a physical model able to reproduce hydraulic transients, generating vacuum pressures through rapid upstream valve closures.

  11. Heat pipe technology for coal-fired power systems

    SciTech Connect

    Uherka, K.L.; Holtz, R.E.; McLennan, G.A.; Koehl, E.R.

    1985-04-01

    This report summarizes the results of heat pipe R and D activities at Argonne National Laboratory (ANL) during the 1977 to 1984 time period. The heat pipe development efforts were associated with a variety of DOE supported projects involving coal-fired prime movers for stationary power generation. The role of heat pipes for these power systems is in their potential application as thermal transport systems for integrating fluidized bed combustors (FBC) with prime movers ranging from Stirling engines in total energy systems (approx.10 MWe) to closed-cycle gas turbines in central power plants (approx.1000 MWe). The results of initial investigations at ANL demonstrated that high-temperature sodium heat pipes provided the best heat exchanger technology for integrating Stirling engines with coal-fired FBC systems. A major accomplishment included the development and validation of a computer code (ANL/HTP) which calculates heat pipe operating limits and other significant characteristics necessary for power plant design. A number of developmental and prototype heat pipes were designed and fabricated through a subcontract effort with Thermacore, Inc., and delivered to ANL for performance testing. Preliminary test results from ANL's Heat Pipe Test Facility, using induction heating and a gas-water calorimeter to establish energy balances, are given in the report. Test data obtained to date are consistent with ANL/HTP code predictions. 47 refs., 53 figs., 22 tabs.

  12. Drill pipe protector development

    SciTech Connect

    Thomerson, C.; Kenne, R.; Wemple, R.P.

    1996-03-01

    The Geothermal Drilling Organization (GDO), formed in the early 1980s by the geothermal industry and the U.S. Department of Energy (DOE) Geothermal Division, sponsors specific development projects to advance the technologies used in geothermal exploration, drilling, and production phases. Individual GDO member companies can choose to participate in specific projects that are most beneficial to their industry segment. Sandia National Laboratories is the technical interface and contracting office for the DOE in these projects. Typical projects sponsored in the past have included a high temperature borehole televiewer, drill bits, muds/polymers, rotary head seals, and this project for drill pipe protectors. This report documents the development work of Regal International for high temperature geothermal pipe protectors.

  13. Design of Refractory Metal Life Test Heat Pipe and Calorimeter

    NASA Technical Reports Server (NTRS)

    Martin, J. J.; Reid, R. S.; Bragg-Sitton, S. M.

    2010-01-01

    Heat pipe life tests have seldom been conducted on a systematic basis. Typically, one or more heat pipes are built and tested for an extended period at a single temperature with simple condenser loading. Results are often reported describing the wall material, working fluid, test temperature, test duration, and occasionally the nature of any failure. Important information such as design details, processing procedures, material assay, power throughput, and radial power density are usually not mentioned. We propose to develop methods to generate carefully controlled data that conclusively establish heat pipe operating life with material-fluid combinations capable of extended operation. The test approach detailed in this Technical Publication will use 16 Mo-44.5%Re alloy/sodium heat pipe units that have an approximate12-in length and 5/8-in diameter. Two specific test series have been identified: (1) Long-term corrosion rates based on ASTM-G-68-80 (G-series) and (2) corrosion trends in a cross-correlation sequence at various temperatures and mass fluences based on a Fisher multifactor design (F-series). Evaluation of the heat pipe hardware will be performed in test chambers purged with an inert purified gas (helium or helium/argon mixture) at low pressure (10-100 torr) to provide thermal coupling between the heat pipe condenser and calorimeter. The final pressure will be selected to minimize the potential for voltage breakdown between the heat pipe and radio frequency (RF) induction coil (RF heating is currently the planned method of powering the heat pipes). The proposed calorimeter is constructed from a copper alloy and relies on a laminar flow water-coolant channel design to absorb and transport energy

  14. Heat Pipe Systems

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Solar Fundamentals, Inc.'s hot water system employs space-derived heat pipe technology. It is used by a meat packing plant to heat water for cleaning processing machinery. Unit is complete system with water heater, hot water storage, electrical controls and auxiliary components. Other than fans and a circulating pump, there are no moving parts. System's unique design eliminates problems of balancing, leaking, corroding, and freezing.

  15. Lightweight concrete OTEC cold water pipe tests, phase 2

    NASA Astrophysics Data System (ADS)

    Oconnor, J. S.

    1981-03-01

    A one third scale model of a cold water pipe (CWP) for a 40 MW/sub ocean thermal energy conversion (OTEC) plantship was constructed of reinforced lightweight concrete and tested to destruction. Failure occurred at approximately 138 percent of the design load for the once in 100 year storm condition in the Atlantic-1 siting area. The concept of using Neoprene bearing pads to provide flexibility of the joint between pipe segments was also verified. Measured deflections and stresses generally agreed with computer generated predictions and validated the design methods used. It is indicated that a light weight concrete CWP can be built with conventional material, and processes.

  16. Underground pipeline laying using the pipe-in-pipe system

    NASA Astrophysics Data System (ADS)

    Antropova, N.; Krets, V.; Pavlov, M.

    2016-09-01

    The problems of resource saving and environmental safety during the installation and operation of the underwater crossings are always relevant. The paper describes the existing methods of trenchless pipeline technology, the structure of multi-channel pipelines, the types of supporting and guiding systems. The rational design is suggested for the pipe-in-pipe system. The finite element model is presented for the most dangerous sections of the inner pipes, the optimum distance is detected between the roller supports.

  17. Guidable pipe plug

    DOEpatents

    Glassell, Richard L.; Babcock, Scott M.; Lewis, Benjamin E.

    2001-01-01

    A plugging device for closing an opening defined by an end of a pipe with sealant comprises a cap, an extension, an inner seal, a guide, and at least one stop. The cap has an inner surface which defines a chamber adapted for retaining the sealant. The chamber is dimensioned slightly larger than the end so as to receive the end. The chamber and end define a gap therebetween. The extension has a distal end and is attached to the inner surface opposite the distal end. The inner seal is attached to the extension and sized larger than the opening. The guide is positioned forward of the inner seal and attached to the distal end. The guide is also dimensioned to be inserted into the opening. The stop is attached to the extender, and when the stop is disposed in the pipe, the stop is movable with respect to the conduit in one direction and also prevents misalignment of the cap with the pipe. A handle can also be included to allow the cap to be positioned robotically.

  18. Eccentric-fluted beam pipes to damp quadrupole higher-order modes

    NASA Astrophysics Data System (ADS)

    Sawamura, M.; Furuya, T.; Sakai, H.; Takahashi, T.; Umemori, K.; Shinoe, K.

    2010-02-01

    An eccentric-fluted beam pipe is proposed to damp quadrupole modes in a cavity. The eccentric flutes act as a mode converter from quadrupole to dipole. Optimizing the parameters of the eccentric-fluted beam pipe allows sufficient damping of both degenerate quadrupole modes. The external Q values of the eccentric-fluted beam pipe measured with a low power model cavity agree well with those calculated with the 3D electromagnetic field simulation code MAFIA.

  19. In Situ Corrosion and Heat Loss Assessment of Two Nonstandard Underground Heat Distribution System Piping Designs

    DTIC Science & Technology

    2011-06-01

    of this specific design consists of a carrier pipe, carrier pipe insulation ( mineral wool ), an annular air space, steel casing, a layer of exterior...excavation site agree with Perma-Pipe “Multi-Therm 500” nominal specs for 10” carrier with 2” mineral wool insulation. 3. Conduit Temperature: Supply...the ASHRAE calculation method or by manufacturer performance claims. MEC is reasonably certain that the mineral wool insulation used by the

  20. Heat pipe technology: A bibliography with abstracts

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The annual supplement on heat pipe technology for 1971 is presented. The document contains 101 references with abstracts and 47 patents. The subjects discussed are: (1) heat pipe applications, (2) heat pipe theory, (3) design, development, and fabrication of heat pipes, (4) testing and operation, (5) subject and author index, and (6) heat pipe related patents.

  1. Thermal blooming on laser propagation in an aspirating pipe

    NASA Astrophysics Data System (ADS)

    Zhu, Fuyin; Wang, Jihong; Ren, Ge; Tan, Yufeng; Zhu, Nengbing; Ai, Zhiwei

    2016-10-01

    Thermal blooming effect of gas on laser propagation can seriously degrade performance of far-field beam quality and energy distribution. Numerical simulation is carried out to study the influences of thermal blooming on laser propagation in line pipes. A physical model of thermal blooming effect of gas on laser propagation in an aspirating pipe is established. Axial flow and suction in the outlet are used to attenuate the thermal blooming effect. Based on the computational fluid dynamics (CFD) software, stable calculation of flow field is carried out first, then the optical field and the fluent field is coupling calculated by means of user defined function (UDF). The results show that radial flow is enhanced in the aspirating pipe and the index of refraction gradient caused by thermal blooming effect is decreased. It is indicated that the beam quality of the outlet is improved compared with the pipe model without aspirating. The optical path difference (OPD) distribution of the outlet is analyzed and decomposed by Zernike polynomials. It is shown that the defocus item of 4m aspirating pipe is decreased more than an order of magnitude compared with the 4m pipe without aspirating.

  2. Boundary Layer Control in Pipes through Strong Injection

    SciTech Connect

    Yeung, William Chor-Chun; Holt, Maurice

    1982-01-01

    In coal gasification, oxidation and sulfidization cause serious pipe corrosion. This study attempts to determine the feasibility of reducing such corrosion by injecting steam at pipe entry to modify the boundary-layer gas composition along pipe walls. The injection will form a thin layer on the inner wall, preventing, for a time, contact with the corrosive gases. (Turbulence will eventually force diffusion through the protective layer.) The gas products are assumed to be hydrogen sulfide and steam. The Method of Integral Relations is used to obtain the numerical solutions to the governing equations. Finally, with several different injectant lengths and velocities, the concentration of H2S along the pipe wall is calculated and is found low enough to prevent corrosion.

  3. Analysis of the thermal performance of heat pipe radiators

    NASA Technical Reports Server (NTRS)

    Boo, J. H.; Hartley, J. G.

    1990-01-01

    A comprehensive mathematical model and computational methodology are presented to obtain numerical solutions for the transient behavior of a heat pipe radiator in a space environment. The modeling is focused on a typical radiator panel having a long heat pipe at the center and two extended surfaces attached to opposing sides of the heat pipe shell in the condenser section. In the set of governing equations developed for the model, each region of the heat pipe - shell, liquid, and vapor - is thermally lumped to the extent possible, while the fin is lumped only in the direction normal to its surface. Convection is considered to be the only significant heat transfer mode in the vapor, and the evaporation and condensation velocity at the liquid-vapor interface is calculated from kinetic theory. A finite-difference numerical technique is used to predict the transient behavior of the entire radiator in response to changing loads.

  4. Thermal performance of heat pipe with suspended nano-particles

    NASA Astrophysics Data System (ADS)

    Shukla, K. N.; Solomon, A. Brusly; Pillai, B. C.; Ruba Singh, B. Jacob; Saravana Kumar, S.

    2012-11-01

    Nanofluids are employed as the working medium for a conventional cylindrical heat pipe. A cylindrical copper heat pipe of 19.5 mm outer diameter and 400 mm length was fabricated and tested with two different working fluids. The working fluids used in this study are DI-water and Nano-particles suspension (mixture of copper nano particle and DI-water). The overall heat transfer coefficient of the heat pipe was calculated based on the lumped thermal resistance network and compared with the heat transfer coefficient of base fluid filled heat pipe. There is a quantitative improvement in the heat transfer coefficient using nano-particles suspension as the working medium. A heat transfer correlation was also developed based on multiple regression least square method and the results were compared with that obtained by the experiment.

  5. Experimenting with a ``Pipe'' Whistle

    NASA Astrophysics Data System (ADS)

    Stafford, Olga

    2012-04-01

    A simple pipe whistle can be made using pieces of PVC pipe. The whistle can be used to measure the resonant frequencies of open or closed pipes. A slightly modified version of the device can be used to also investigate the interesting dependence of the sound frequencies produced on the orifice-to-edge distance. The pipe whistle described here allows students in a physics of music or introductory physics course to study an example of an "edge tone" device that produces discrete sound frequencies. From their textbooks, students likely know about standing waves produced by pipes or strings, as well as the resonant frequencies for open and closed pipes. To go a bit further, they can also learn how the frequency of the sound wave depends on the orifice-to-edge distance of the wind instrument.

  6. Two-phase flow in horizontal pipes

    SciTech Connect

    Maeder, P.F.; Michaelides, E.E.; DiPippo, R.

    1981-09-01

    A method is developed in this paper which calculates the two-phase flow friction factor at any state of the fluid in the pipe. The mixing-length theory was employed for the calculation of the Reynolds stresses in turbulent two-phase flow. The friction factors obtained this way are in good agreement with experimental data. It is clear that the choice of the parameter m, or the density distribution, is rather arbitrary. Careful experimentation is required to refine the analysis given in this study, and in particular to provide guidance in the proper selection of the parameter m.

  7. Radiation crosslinked plasticized PVC - pipes

    NASA Astrophysics Data System (ADS)

    Hell, Z.; Ravlić, M.; Bogdanović, Lj.; Maleš, J.; Dvornik, I.; Ranogajec, F.; Ranogajec, M.; Tudorić-Ghemo, J.

    The efficiency of polyfunctional monomers triallyl cyanurate, allyl methacrylate, diallyl phtalate, 2-ethyl-2(hydroxy-methyl)-propanediol-(1,3) trimethacrylate, divinyl benzene and ethylene glycol dimethacrylate in radiation crosslinking of PVC was investigated. Patterns of pipes were produced and irradiated with gamma rays. The resistance to internal pressure of crosslinked PVC pipes was measured at 80°C and compared with resistance of unirradiated PVC pipes.

  8. Insulating Cryogenic Pipes With Frost

    NASA Technical Reports Server (NTRS)

    Stephenson, J. G.; Bova, J. A.

    1985-01-01

    Crystallized water vapor fills voids in pipe insulation. Small, carefully controlled amount of water vapor introduced into dry nitrogen gas before it enters aft fuselage. Vapor freezes on pipes, filling cracks in insulation. Ice prevents gaseous nitrogen from condensing on pipes and dripping on structure, in addition to helping to insulate all parts. Industrial applications include large refrigeration plants or facilities that use cryogenic liquids.

  9. Cryogenic Heat Pipe Experiment (CRYOHP)

    NASA Technical Reports Server (NTRS)

    Mcintosh, Roy

    1992-01-01

    The objective of the CRYOHP experiment is to conduct a shuttle experiment that demonstrates the reliable operation of two oxygen heat pipes in microgravity. The experiment will perform the following tasks: (1) demonstrate startup of the pipes from the supercritical state; (2) measure the heat transport capacity of the pipes; (3) measure evaporator and condenser film coefficients; and (4) work shuttle safety issues. The approach for the experiment is as follows: (1) fly two axially grooved oxygen heat pipes attached to mechanical stirling cycle tactical coolers; (2) integrate experiment in hitch-hiker canister; and (3) fly on shuttle and control from ground.

  10. Thermostructural applications of heat pipes

    NASA Technical Reports Server (NTRS)

    Peeples, M. E.; Reeder, J. C.; Sontag, K. E.

    1979-01-01

    The feasibility of integrating heat pipes in high temperature structure to reduce local hot spot temperature was evaluated for a variety of hypersonic aerospace vehicles. From an initial list of twenty-two potential applications, the single stage to orbit wing leading edge showed the greatest promise and was selected for preliminary design of an integrated heat pipe thermostructural system. The design consisted of a Hastelloy X assembly with sodium heat pipe passages aligned normal to the wing leading edge. A d-shaped heat pipe cross section was determined to be optimum from the standpoint of structural weight.

  11. 46 CFR 76.33-15 - Piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... System, Details § 76.33-15 Piping. (a) Individual pipes shall be not less than 3/4-inch standard pipe... with as easy bends as practicable, and shall be installed to grade to low points for drainage. (e...

  12. 46 CFR 76.33-15 - Piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... System, Details § 76.33-15 Piping. (a) Individual pipes shall be not less than 3/4-inch standard pipe... with as easy bends as practicable, and shall be installed to grade to low points for drainage. (e...

  13. 46 CFR 76.33-15 - Piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... System, Details § 76.33-15 Piping. (a) Individual pipes shall be not less than 3/4-inch standard pipe... with as easy bends as practicable, and shall be installed to grade to low points for drainage. (e...

  14. Piping and equipment resistance to seismic-generated missiles

    SciTech Connect

    LaSalle, F.R.; Golbeg, P.R.; Chenault, D.M.

    1992-02-01

    For reactor and nuclear facilities, both Title 10, Code of Federal Regulations, Part 50, and US Department of Energy Order 6430.1A require assessments of the interaction of non-Safety Class 1 piping and equipment with Safety Class 1 piping and equipment during a seismic event to maintain the safety function. The safety class systems of nuclear reactors or nuclear facilities are designed to the applicable American Society of Mechanical Engineers standards and Seismic Category 1 criteria that require rigorous analysis, construction, and quality assurance. Because non-safety class systems are generally designed to lesser standards and seismic criteria, they may become missiles during a safe shutdown earthquake. The resistance of piping, tubing, and equipment to seismically generated missiles is addressed in the paper. Gross plastic and local penetration failures are considered with applicable test verification. Missile types and seismic zones of influence are discussed. Field qualification data are also developed for missile evaluation.

  15. Uplifting behavior of shallow buried pipe in liquefiable soil by dynamic centrifuge test.

    PubMed

    Huang, Bo; Liu, Jingwen; Lin, Peng; Ling, Daosheng

    2014-01-01

    Underground pipelines are widely applied in the so-called lifeline engineerings. It shows according to seismic surveys that the damage from soil liquefaction to underground pipelines was the most serious, whose failures were mainly in the form of pipeline uplifting. In the present study, dynamic centrifuge model tests were conducted to study the uplifting behaviors of shallow-buried pipeline subjected to seismic vibration in liquefied sites. The uplifting mechanism was discussed through the responses of the pore water pressure and earth pressure around the pipeline. Additionally, the analysis of force, which the pipeline was subjected to before and during vibration, was introduced and proved to be reasonable by the comparison of the measured and the calculated results. The uplifting behavior of pipe is the combination effects of multiple forces, and is highly dependent on the excess pore pressure.

  16. Uplifting Behavior of Shallow Buried Pipe in Liquefiable Soil by Dynamic Centrifuge Test

    PubMed Central

    Liu, Jingwen; Ling, Daosheng

    2014-01-01

    Underground pipelines are widely applied in the so-called lifeline engineerings. It shows according to seismic surveys that the damage from soil liquefaction to underground pipelines was the most serious, whose failures were mainly in the form of pipeline uplifting. In the present study, dynamic centrifuge model tests were conducted to study the uplifting behaviors of shallow-buried pipeline subjected to seismic vibration in liquefied sites. The uplifting mechanism was discussed through the responses of the pore water pressure and earth pressure around the pipeline. Additionally, the analysis of force, which the pipeline was subjected to before and during vibration, was introduced and proved to be reasonable by the comparison of the measured and the calculated results. The uplifting behavior of pipe is the combination effects of multiple forces, and is highly dependent on the excess pore pressure. PMID:25121140

  17. Large-bore pipe decontamination

    SciTech Connect

    Ebadian, M.A.

    1998-01-01

    The decontamination and decommissioning (D and D) of 1200 buildings within the US Department of Energy-Office of Environmental Management (DOE-EM) Complex will require the disposition of miles of pipe. The disposition of large-bore pipe, in particular, presents difficulties in the area of decontamination and characterization. The pipe is potentially contaminated internally as well as externally. This situation requires a system capable of decontaminating and characterizing both the inside and outside of the pipe. Current decontamination and characterization systems are not designed for application to this geometry, making the direct disposal of piping systems necessary in many cases. The pipe often creates voids in the disposal cell, which requires the pipe to be cut in half or filled with a grout material. These methods are labor intensive and costly to perform on large volumes of pipe. Direct disposal does not take advantage of recycling, which could provide monetary dividends. To facilitate the decontamination and characterization of large-bore piping and thereby reduce the volume of piping required for disposal, a detailed analysis will be conducted to document the pipe remediation problem set; determine potential technologies to solve this remediation problem set; design and laboratory test potential decontamination and characterization technologies; fabricate a prototype system; provide a cost-benefit analysis of the proposed system; and transfer the technology to industry. This report summarizes the activities performed during fiscal year 1997 and describes the planned activities for fiscal year 1998. Accomplishments for FY97 include the development of the applicable and relevant and appropriate regulations, the screening of decontamination and characterization technologies, and the selection and initial design of the decontamination system.

  18. Polymeric heat pipe wick

    NASA Astrophysics Data System (ADS)

    Seidenberg, Benjamin

    1988-08-01

    A wick for use in a capillary loop pump heat pipe is described. The wick material is an essentially uniformly porous, permeable, open-cell, polyethylene thermoplastic foam having an ultrahigh average molecular weight of from approximately 1 to 5 million, and an average pore size of about 10 to 12 microns. A representative material having these characteristics is POREX UF, which has an average molecular weight of about 3 million. This material is fully compatible with the FREONs and anhydrous ammonia and allows for the use of these very efficient working fluids in capillary loops.

  19. Ceramic heat pipe wick

    NASA Technical Reports Server (NTRS)

    Seidenberg, Benjamin (Inventor); Swanson, Theodore (Inventor)

    1989-01-01

    A wick for use in a capillary loop pump heat pipe is disclosed. The wick material is an essentially uniformly porous, permeable, open-cell, silicon dioxide/aluminum oxide inorganic ceramic foam having a silica fiber ratio, by weight, of about 78 to 22, respectively, a density of 6 lbs/cu ft, and an average pore size of less than 5 microns. A representative material having these characteristics is Lockheed Missile and Space Company, Inc.'s HTP 6-22. This material is fully compatible with the freons and anhydrous ammonia and allows for the use of these very efficient working fluids, and others, in capillary loops.

  20. Analysis of frozen startup of high-temperature heat pipes and three-dimensional modeling of block-heated heat pipes

    NASA Astrophysics Data System (ADS)

    Faghri, Amir

    1991-11-01

    The use of high-temperature heat pipes has been proposed for cooling the leading edges and nose cones of re-entry vehicles, rail guns, and laser mirrors, as well as for the thermal management of future hypersonic vehicle structures. The startup behavior of high temperature heat pipes from the frozen state was investigated both numerically and experimentally for various heat loads and input locations. A high temperature sodium/stainless steel heat pipe with multiple heat sources and sinks was fabricated, processed, and tested. A numerical simulation of the transient heat pipe performance including the vapor region, wick structure, and the heat pipe wall is given. Furthermore, experimental and numerical analyses of several operating parameters of a low-temperature copper-water heat pipe under uniform circumferential heating and block heating has been performed. Finally, a numerical analysis of transient heat pipe performance including nonconventional heat pipes with nonuniform heat distributions is presented. Numerical calculations were then made for a leading edge heat pipe with localized high heat fluxes.

  1. Fluid-structure interaction in water-filled thin pipes of anisotropic composite materials

    NASA Astrophysics Data System (ADS)

    You, Jeong Ho; Inaba, K.

    2013-01-01

    The effects of elastic anisotropy in piping materials on fluid-structure interaction are studied for water-filled carbon-fiber reinforced thin plastic pipes. When an impact is introduced to water in a pipe, there are two waves traveling at different speeds. A primary wave corresponding to a breathing mode of pipe travels slowly and a precursor wave corresponding to a longitudinal mode of pipe travels fast. An anisotropic stress-strain relationship of piping materials has been taken into account to describe the propagation of primary and precursor waves in the carbon-fiber reinforced thin plastic pipes. The wave speeds and strains in the axial and hoop directions are calculated as a function of carbon-fiber winding angles and compared with the experimental data. As the winding angle increases, the primary wave speed increases due to the increased stiffness in the hoop direction, while the precursor wave speed decreases. The magnitudes of precursor waves are much smaller than those of primary waves so that the effect of precursor waves on the deformation of pipe is not significant. The primary wave generates the hoop strain accompanying the opposite-signed axial strain through the coupling compliance of pipe. The magnitude of hoop strain induced by the primary waves decreases with increasing the winding angle due to the increased hoop stiffness of pipe. The magnitude of axial strain is small at low and high winding angles where the coupling compliance is small.

  2. Pipe crawler with stabilizing midsection

    DOEpatents

    Zollinger, W.T.; Treanor, R.C.

    1994-12-27

    A pipe crawler is described having a midsection that provides the stability and flexibility to allow the pipe crawler to negotiate curved and uneven segments of piping while traveling through piping systems. The pipe crawler comprises a front leg assembly, a rear leg assembly, a midsection with a gimbal at each end for connecting the midsection to the front and rear leg assemblies in a flexible manner, and an air cylinder for changing the distance between the front and rear leg assemblies. The pipe crawler moves in ''inch worm'' fashion with the front and rear leg assemblies alternating between an extended and a retracted position as the air cylinder moves the retracted leg assembly forward. The midsection has a plurality of legs extending radially for holding the midsection within a maximum displacement from the piping axis so that the gimbals are not pivoted to extreme angles where they might lock up or seize. When the midsection is displaced sufficiently, its legs with wheels on each end engage the interior surface of the piping and prevent further displacement. Using two gimbals divides the angle between the planes defined by the front and rear leg assemblies which also helps to prevent excessive gimbal pivoting. 5 figures.

  3. Pipe crawler with stabilizing midsection

    DOEpatents

    Zollinger, William T.; Treanor, Richard C.

    1994-01-01

    A pipe crawler having a midsection that provides the stability and flexibty to allow the pipe crawler to negotiate curved and uneven segments of piping while traveling through piping systems. The pipe crawler comprises a front leg assembly, a rear leg assembly, a midsection with a gimbal at each end for connecting the midsection to the front and rear leg assemblies in a flexible manner, and an air cylinder for changing the distance between the front and rear leg assemblies. The pipe crawler moves in "inch worm" fashion with the front and rear leg assemblies alternating between an extended and a retracted position as the air cylinder moves the retracted leg assembly forward. The midsection has a plurality of legs extending radially for holding the midsection within a maximum displacement from the piping axis so that the gimbals are not pivoted to extreme angles where they might lock up or seize. When the midsection is displaced sufficiently, its legs with wheels on each end engage the interior surface of the piping and prevent further displacement. Using two gimbals divides the angle between the planes defined by the front and rear leg assemblies which also helps to prevent excessive gimbal pivoting.

  4. Heat Pipe Blocks Return Flow

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.

    1982-01-01

    Metal-foil reed valve in conventional slab-wick heat pipe limits heat flow to one direction only. With sink warmer than source, reed is forced closed and fluid returns to source side through annular transfer wick. When this occurs, wick slab on sink side of valve dries out and heat pipe ceases to conduct heat.

  5. Demonstrating Sound Impulses in Pipes.

    ERIC Educational Resources Information Center

    Raymer, M. G.; Micklavzina, Stan

    1995-01-01

    Describes a simple, direct method to demonstrate the effects of the boundary conditions on sound impulse reflections in pipes. A graphical display of the results can be made using a pipe, cork, small hammer, microphone, and fast recording electronics. Explains the principles involved. (LZ)

  6. Building a Copper Pipe "Xylophone."

    ERIC Educational Resources Information Center

    Lapp, David R.

    2003-01-01

    Explains how to use the equation for frequency of vibration of a transversely oscillating bar or pipe with both ends free to vibrate to build a simple and inexpensive xylophone from a 3-meter section of copper pipe. The instrument produces a full major scale and can be used to investigate various musical intervals. (Author/NB)

  7. Heat Pipe Thermal Conditioning Panel

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.

    1973-01-01

    The development, fabrication, and evaluation of heat pipe thermal conditioning panels are discussed. The panels were designed and fabricated to be compatible with several planned NASA space vehicles, in terms of panel size, capacity, temperature gradients, and integration with various heat exchangers and electronic components. It was satisfactorily demonstrated that the heat pipe thermal conditioning panel meets the thermal efficiency and heat transport requirements.

  8. Water flows from slotted pipes

    SciTech Connect

    Olson, D.A.

    1981-04-01

    Results of experiments and analyses that determine jet flow distribution from slotted pipes of dimensions typical for OC-OTEC evaporators or condensers are described. For a pipe with a 6.3-cm inside diameter and 0.64-cm wide slot, the measured and predicted jet flow was low and nearly parallel to the pipe at the entrance, and high and perpendicular to the pipe only near the closed end. Slot lengths ranged from 1.5 m to 4.6 m, and inlet flow rates varied from 6 kg/s to 17 kg/s. Friction reduces the pressure in the entrance and intermediate portions of the pipe, while the rapidly decelerating flow produces high pressure recovery as it approaches the closed end. In the region of high flow next to the closed end, the ratio of slot area (slot length times width) to pipe cross-sectional area is less than two. To use a slotted pipe for generating falling jets in an OC-OTEC plant, the slot length should be 1 m or less (for a pipe with a 6.3-cm inside diameter and a 0.64-cm wide slot).

  9. Building a Copper Pipe "Xylophone."

    ERIC Educational Resources Information Center

    Lapp, David R.

    2003-01-01

    Explains how to use the equation for frequency of vibration of a transversely oscillating bar or pipe with both ends free to vibrate to build a simple and inexpensive xylophone from a 3-meter section of copper pipe. The instrument produces a full major scale and can be used to investigate various musical intervals. (Author/NB)

  10. Demonstrating Sound Impulses in Pipes.

    ERIC Educational Resources Information Center

    Raymer, M. G.; Micklavzina, Stan

    1995-01-01

    Describes a simple, direct method to demonstrate the effects of the boundary conditions on sound impulse reflections in pipes. A graphical display of the results can be made using a pipe, cork, small hammer, microphone, and fast recording electronics. Explains the principles involved. (LZ)

  11. High temperature loop heat pipes

    SciTech Connect

    Anderson, W.G.; Bland, J.J.; Fershtater, Y.; Goncharov, K.A.; Nikitkin, M.; Juhasz, A.

    1995-12-31

    Advantages of loop heat pipes over conventional heat pipes include self-priming during start-up, improved tolerance for noncondensible gas, and ability for ground testing in any orientation. The applications for high temperature, alkali-metal working fluid loop heat pipes include space radiators, and bimodal systems. A high temperature loop heat pipe was fabricated and tested at 850 K, using cesium as the working fluid. Previous loop heat pipes were tested with ambient temperature working fluids at temperatures below about 450 K. The loop heat pipe had a titanium envelope, and a titanium aluminide wick. The maximum cesium loop heat pipe power was only about 600 watts, which was lower the predicted 1,000 W power. The power limitation may be due to a wettability problem with the cesium not completely wetting the titanium aluminide wick. This would reduce the pumping capability of the wick, and the maximum power that the heat pipe could carry. This problem could be solved by using a refractory metal powder wick, since the alkali metals are known to wet refractory metal wicks.

  12. Alternate high capacity heat pipe

    NASA Technical Reports Server (NTRS)

    Voss, F. E.

    1986-01-01

    The performance predictions for a fifty foot heat pipe (4 foot evaporator - 46 foot condensor) are discussed. These performance predictions are supported by experimental data for a four foot heat pipe. Both heat pipes have evaporators with axial groove wick structures and condensers with powder metal external artery wick structures. The predicted performance of a rectangular axial groove/external artery heat pipe operating in space is given. Heat transport versus groove width is plotted for 100, 200 and 300 grooves in the evaporator. The curves show that maximum power is achieved for groove widths from 0.040 to 0.053 as the number of grooves varies from 300 to 100. The corresponding range of maximum power is 3150 to 2400 watts. The relationships between groove width and heat pipe evaporate diameter for 100, 200 and 300 grooves in the evaporator are given. A four foot heat pipe having a three foot condenser and one foot evaporator was built and tested. The evaporator wick structure used axial grooves with rectangular cross sections, and the condenser wick structure used powder metal with an external artery configuration. Fabrication drawings are enclosed. The predicted and measured performance for this heat pipe is shown. The agreement between predicted and measured performance is good and therefore substantiates the predicted performance for a fifty foot heat pipe.

  13. Electron cloud density measurements in accelerator beam-pipe using resonant microwave excitation

    NASA Astrophysics Data System (ADS)

    Sikora, John P.; Carlson, Benjamin T.; Duggins, Danielle O.; Hammond, Kenneth C.; De Santis, Stefano; Tencate, Alister J.

    2014-08-01

    An accelerator beam can generate low energy electrons in the beam-pipe, generally called electron cloud, that can produce instabilities in a positively charged beam. One method of measuring the electron cloud density is by coupling microwaves into and out of the beam-pipe and observing the response of the microwaves to the presence of the electron cloud. In the original technique, microwaves are transmitted through a section of beam-pipe and a change in EC density produces a change in the phase of the transmitted signal. This paper describes a variation on this technique in which the beam-pipe is resonantly excited with microwaves and the electron cloud density calculated from the change that it produces in the resonant frequency of the beam-pipe. The resonant technique has the advantage that measurements can be localized to sections of beam-pipe that are a meter or less in length with a greatly improved signal to noise ratio.

  14. Inner-pipe structure to improve column heterogeneity and peak shape.

    PubMed

    Hu, Di; Mei, Xiang; Shi, Pengchao; Zhou, Xin

    2015-04-01

    Column heterogeneity plays an important role in peak tailing and asymmetric profiles. We have designed a novel column structure (concentric column structure) that has a concentric inner-pipe nested in a column. This structure was studied by a number calculation method and wider diameter column experiments. The results showed that column heterogeneity and column efficiency were improved by inner-pipe structure. Moreover, the results showed that high-efficiency columns were stronger influenced by inner-pipe structure than low-efficiency columns. The influence of an inner-pipe was related to its size. The optimal inner-pipe diameter was nearly 0.625 times of column diameter. By using inner-pipe structure in this way, it was possible to decrease column heterogeneity and increase column efficiency of a wide-diameter column. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. The reflection of guided waves from simple dents in pipes.

    PubMed

    Ma, Shuyi; Wu, Zhanjun; Wang, Yishou; Liu, Kehai

    2015-03-01

    Guided elastic waves have been anticipated as a rapid screening technique for pipe inspection. Dents occurring in pipes are a severe problem which may lead to the possibility of pipe failure. A study of the reflection characteristics of guided waves from dents of varying geometrical profile in pipes is investigated through experiments. Dented region is represented by a series of circumferential cross-sections and its geometric parameters are described by axial length and the maximum and minimum outer diameters. Both single and double sided dents are mechanically simulated in hollow aluminum pipes and then experimentally tested by exciting the longitudinal L(0,2) mode. A quantitative parameter, so-called deformation rate relating to the maximum and minimum outer diameters of the dents is defined to evaluate the effect of the extent of the deformation on the reflection. For both types of dents, it is shown that the reflection coefficients of the L(0,2) mode are all approximately a linear function of their respective deformation rates. Mode conversion occurs at the dents and reflections of the F(1,3) mode are identified. The results show that the amplitude of the reflected F(1,3) mode is generally higher when the dent has stronger non-axisymmetric features. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Flow Pressure Loss through Straight Annular Corrugated Pipes

    NASA Technical Reports Server (NTRS)

    Sargent, Joseph R.; Kirk, Daniel R.; Marsell, Brandon; Roth, Jacob; Schallhorn, Paul A.; Pitchford, Brian; Weber, Chris; Bulk, Timothy

    2016-01-01

    Pressure loss through annular corrugated pipes, using fully developed gaseous nitrogen representing purge pipes in spacecraft fairings, was studied to gain insight into a friction factor coefficient for these pipes. Twelve pipes were tested: four Annuflex, four Masterflex and two Titeflex with ¼”, 3/8”, ½” and ¾” inner diameters. Experimental set-up was validated using smooth-pipe and showed good agreement to the Moody diagram. Nitrogen flow rates between 0-200 standard cubic feet per hour were used, producing approximate Reynolds numbers from 300-23,000. Corrugation depth varied from 0.248 = E/D = 0.349 and relative corrugation pitch of 0.192 = P/D = 0.483. Differential pressure per unit length was measured and calculated using 8-9 equidistant pressure taps. A detailed experimental uncertainty analysis, including correlated bias error terms, is presented. Results show larger differential pressure losses than smooth-pipes with similar inner diameters resulting in larger friction factor coefficients.

  17. Report of ad hoc OTEC cold water pipe committee

    SciTech Connect

    Barr, R.; Giannotti, J.; Deuchler, W.; Scotti, R.; Stadter, J.; Walsh, J. P.; Weiss, R.

    1980-02-01

    Now that the design work on the pilot plant is scheduled to start in the near future, DOE has considered it essential that an overall look be taken at the cold water pipe design process. The VSE Corporation, in its role as a support contractor to DOE, was tasked to organize a small study group to answer the question, Where do we stand on the verification of the computer models of the cold water pipe response by experimental measurements. The committee has studied all the available results of the cold water pipe development program. This report summarizes those results. The development and present capabilities of the computer programs used to calculate the response of a cold water pipe attached to a platform under known at-sea conditions are discussed. The various cold water pipe designs that have been done using the computer programs are summarized. The experiments that have been conducted up to the present time to measure the response of cold water pipes at-sea and in experimental tanks are described. The results of these experiments are presented. The experimental results are compared with the predictions made with the analytical computer programs. Conclusions drawn as a result of this analysis are presented and some recommendations are made. (WHK)

  18. Effect of pipe sags on wastewater collection system performance.

    PubMed

    Sever, V Firat; Foust, Henry

    2011-04-01

    Sagging of pipelines is a common problem in centralized wastewater collection systems. Wastewater flowing through sags experiences several changes of slope, and the flow through flat and negative slope sections is prone to a significant reduction in mean velocity. The objective of this study is to determine when pipe sags would result in significant velocities below design conditions, which also would increase the risk of a sewer backup. A sagged pipe configuration that could be encountered in sanitary sewer systems was depicted; thereby, analyses on uniform and gradually varied flows were conducted to determine velocity profiles through different segments of the sagged pipeline setup used for the study. The results indicate that there are significant occurrences when either the velocity in the pipe sags goes below minimum, as recommended in the Ten States Standards (Health Research, Inc., 2004) (0.61 m/s [2.0 ft/ sec]), or flow depth rises to pipe diameter (full section flow). Additionally, velocities along a sagged pipe were calculated for temporal flow rates to account for daily and seasonal flow rate changes in a typical wastewater collection system. Results of the temporal flow rate analysis suggest that, for a 200-mm (8-in.) diameter sagged pipe segment with full-section (wet weather) flow, 75% of the mean velocities would be below the minimum velocity recommended as a Ten States Standard.

  19. Vapor spill pipe monitor

    DOEpatents

    Bianchini, G.M.; McRae, T.G.

    1983-06-23

    The invention is a method and apparatus for continually monitoring the composition of liquefied natural gas flowing from a spill pipe during a spill test by continually removing a sample of the LNG by means of a probe, gasifying the LNG in the probe, and sending the vaporized LNG to a remote ir gas detector for analysis. The probe comprises three spaced concentric tubes surrounded by a water jacket which communicates with a flow channel defined between the inner and middle, and middle and outer tubes. The inner tube is connected to a pump for providing suction, and the probe is positioned in the LNG flow below the spill pipe with the tip oriented partly downward so that LNG is continuously drawn into the inner tube through a small orifice. The probe is made of a high thermal conductivity metal. Hot water is flowed through the water jacket and through the flow channel between the three tubes to provide the necessary heat transfer to flash vaporize the LNG passing through the inner channel of the probe. The gasified LNG is transported through a connected hose or tubing extending from the probe to a remote ir sensor which measures the gas composition.

  20. Vapor spill pipe monitor

    NASA Astrophysics Data System (ADS)

    Bianchini, G. M.; McRae, T. G.

    1983-06-01

    The invention is a method and apparatus for continually monitoring the composition of liquefied natural gas flowing from a spill pipe during a spill test by continually removing a sample of the LNG by means of a probe, gasifying the LNG in the probe, and sending the vaporized LNG to a remote IR gas detector for analysis. The probe comprises three spaced concentric tubes surrounded by a water jacket which communicates with a flow channel defined between the inner and middle, and middle and outer tubes. The inner tube is connected to a pump for providing suction, and the probe is positioned in the LNG flow below the spill pipe with the tip oriented partly downward so that LNG is continuously drawn into the inner tube through a small orifice. The probe is made of a high thermal conductivity metal. Hot water is flowed through the water jacket and through the flow channel between the three tubes to provide the necessary heat transfer to flash vaporize the LNG passing through the inner channel of the probe. The gasified LNG is transported through a connected hose or tubing extending from the probe to a remote IR sensor which measures the gas composition.

  1. Prometheus Hot Leg Piping Concept

    SciTech Connect

    Gribik, Anastasia M.; DiLorenzo, Peter A.

    2007-01-30

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  2. Promethus Hot Leg Piping Concept

    SciTech Connect

    AM Girbik; PA Dilorenzo

    2006-01-24

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  3. Geothermal district piping - A primer

    SciTech Connect

    Rafferty, K.

    1989-11-01

    Transmission and distribution piping constitutes approximately 40 -60% of the capital costs of typical geothermal district heating systems. Selections of economical piping suitable for the fluid chemistry is critical. Presently, most piping (56%) in geothermal systems is of asbestos cement construction. Some fiberglass (19%) and steel (19%) is also in use. Identification of an economical material to replace asbestos cement is important to future project development. By providing information on relative costs, purchase considerations, existing material performance and new products, this report seeks to provide a background of information to the potential pipe purchaser. A brief discussion of the use of uninsulated piping in geothermal district heating systems is also provided. 5 refs., 19 figs., 1 tab.

  4. Prometheus Hot Leg Piping Concept

    NASA Astrophysics Data System (ADS)

    Gribik, Anastasia M.; DiLorenzo, Peter A.

    2007-01-01

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  5. Flexible ultrasonic pipe inspection apparatus

    DOEpatents

    Jenkins, Charles F.; Howard, Boyd D.

    1998-01-01

    A flexible, modular ultrasonic pipe inspection apparatus, comprising a flexible, hollow shaft that carries a plurality of modules, including at least one rotatable ultrasonic transducer, a motor/gear unit, and a position/signal encoder. The modules are connected by flexible knuckle joints that allow each module of the apparatus to change its relative orientation with respect to a neighboring module, while the shaft protects electrical wiring from kinking or buckling while the apparatus moves around a tight corner. The apparatus is moved through a pipe by any suitable means, including a tether or drawstring attached to the nose or tail, differential hydraulic pressure, or a pipe pig. The rotational speed of the ultrasonic transducer and the forward velocity of the apparatus are coordinated so that the beam sweeps out the entire interior surface of the pipe, enabling the operator to accurately assess the condition of the pipe wall and determine whether or not leak-prone corrosion damage is present.

  6. Probabilistic pipe fracture evaluations for leak-rate-detection applications

    SciTech Connect

    Rahman, S.; Ghadiali, N.; Paul, D.; Wilkowski, G.

    1995-04-01

    Regulatory Guide 1.45, {open_quotes}Reactor Coolant Pressure Boundary Leakage Detection Systems,{close_quotes} was published by the U.S. Nuclear Regulatory Commission (NRC) in May 1973, and provides guidance on leak detection methods and system requirements for Light Water Reactors. Additionally, leak detection limits are specified in plant Technical Specifications and are different for Boiling Water Reactors (BWRs) and Pressurized Water Reactors (PWRs). These leak detection limits are also used in leak-before-break evaluations performed in accordance with Draft Standard Review Plan, Section 3.6.3, {open_quotes}Leak Before Break Evaluation Procedures{close_quotes} where a margin of 10 on the leak detection limit is used in determining the crack size considered in subsequent fracture analyses. This study was requested by the NRC to: (1) evaluate the conditional failure probability for BWR and PWR piping for pipes that were leaking at the allowable leak detection limit, and (2) evaluate the margin of 10 to determine if it was unnecessarily large. A probabilistic approach was undertaken to conduct fracture evaluations of circumferentially cracked pipes for leak-rate-detection applications. Sixteen nuclear piping systems in BWR and PWR plants were analyzed to evaluate conditional failure probability and effects of crack-morphology variability on the current margins used in leak rate detection for leak-before-break.

  7. Morbidity profile of steel pipe production workers.

    PubMed

    Pandit, Kirti; Tiwari, Rajnarayan R

    2008-08-01

    To study the different morbid conditions among steel pipe producing workers. The present cross-sectional study has been carried out among the workers of one of the steel pipes and tubes manufacturing factory of Gujarat. Hundred workers from the four major departments of the steel pipe production plant, namely welding, pressing machine, X-ray welding and loading/transportation department were covered. The information regarding demographic, occupational, clinical characteristics and diagnosis were recorded on a pre-designed proforma. Statistical analysis included calculation of percentages and proportions and was carried out using the statistical software Epi Info Version 3.3.2. The mean age of the study subjects was found to be 38.7+/-7.1 years. The mean duration of exposure was found to be 9.0+/-3.4 years. Forty-four percent of the subjects had an upper respiratory tract infection, as evidenced by symptoms like dry cough, cough with rhinitis and cough with fever. Symptoms suggestive of allergic bronchitis were observed in 12% of the subjects while symptoms suggestive of heat stress such as prickly heat, dehydration, perspiration and pyrexia were observed in 13% of the subjects.

  8. Morbidity profile of steel pipe production workers

    PubMed Central

    Pandit, Kirti; Tiwari, Rajnarayan R.

    2008-01-01

    Objective: To study the different morbid conditions among steel pipe producing workers. Methods: The present cross-sectional study has been carried out among the workers of one of the steel pipes and tubes manufacturing factory of Gujarat. Hundred workers from the four major departments of the steel pipe production plant, namely welding, pressing machine, X-ray welding and loading/transportation department were covered. The information regarding demographic, occupational, clinical characteristics and diagnosis were recorded on a pre-designed proforma. Statistical analysis included calculation of percentages and proportions and was carried out using the statistical software Epi Info Version 3.3.2. Results: The mean age of the study subjects was found to be 38.7±7.1 years. The mean duration of exposure was found to be 9.0±3.4 years. Forty-four percent of the subjects had an upper respiratory tract infection, as evidenced by symptoms like dry cough, cough with rhinitis and cough with fever. Symptoms suggestive of allergic bronchitis were observed in 12% of the subjects while symptoms suggestive of heat stress such as prickly heat, dehydration, perspiration and pyrexia were observed in 13% of the subjects. PMID:20040985

  9. Determination of leakage areas in nuclear piping

    SciTech Connect

    Keim, E.

    1997-04-01

    For the design and operation of nuclear power plants the Leak-Before-Break (LBB) behavior of a piping component has to be shown. This means that the length of a crack resulting in a leak is smaller than the critical crack length and that the leak is safely detectable by a suitable monitoring system. The LBB-concept of Siemens/KWU is based on computer codes for the evaluation of critical crack lengths, crack openings, leakage areas and leakage rates, developed by Siemens/KWU. In the experience with the leak rate program is described while this paper deals with the computation of crack openings and leakage areas of longitudinal and circumferential cracks by means of fracture mechanics. The leakage areas are determined by the integration of the crack openings along the crack front, considering plasticity and geometrical effects. They are evaluated with respect to minimum values for the design of leak detection systems, and maximum values for controlling jet and reaction forces. By means of fracture mechanics LBB for subcritical cracks has to be shown and the calculation of leakage areas is the basis for quantitatively determining the discharge rate of leaking subcritical through-wall cracks. The analytical approach and its validation will be presented for two examples of complex structures. The first one is a pipe branch containing a circumferential crack and the second one is a pipe bend with a longitudinal crack.

  10. Study and Analysis of Heat Transfer Limitation of Separated Heat Pipe

    NASA Astrophysics Data System (ADS)

    Mou, Qizheng; Mou, Kai

    2002-01-01

    satellite and spacecraft. evaporator, heat isolation and condenser along the axial direction. The working fluid absorbs heat and evaporates in evaporator, and then the vapor flows to condenser and gives out heat. The condensed liquid is pumped to evaporator by wick. By the circulation, the heat can by transferred continuously. heat pipe as follow: - Vapor-liquid two phase flow inside pipe; - The manner of latent heat to transfer heat; - Automatic circulation by working fluid flowing - A certain extent of vacuum. and the traditional heat pipe, that is, the vapor fluid and liquid fluid flow along the same direction. So it is obviously that the separated heat pipe has special internal heat transfer characteristic and crisis. This paper has regard for the heat transfer crisis of the separated heat pipe, and meanwhile relevant calculation and analysis have been done. 1. FLOW TYPE OF THE WORKING FLUID IN SEPARATED HEAT PIPE 2. HEAT TRANSFER CRISIS IN THE EVAPORATOR 3. CARRYING PHENOMENON INSIDE SEPARATED HEAT PIPE 4. THE STAGNANT FLOW PHENOMENON AND THE BACKWARD FLOW PHENOMENON IN EVAPORATOR CONCLUSION transfer limitation of location burn-out, and the heat transfer limitation of flow unconventionality in erective pipe. The carrying phenomenon can occurs not only in evaporator but also in condenser of separated heat pipe. It is in the evaporator that should take place the heat transfer limitation of liquid film dry-out at first. Then with the increasing of heat flux, the heat transfer limitation of location burn-out would happen. In order to avoid the heat transfer limitation of flow unconventionality in erective pipe, the length and diameter of the outflow tube and inflow tube must be reasonably calculated to control the flow velocity of the working fluid inside pipe. Key words:Separated Heat PipeHeat Transfer LimitationDry-OutCarryingStagnancy

  11. Eddy Current Testing with Giant Magnetoresistance (GMR) Sensors and a Pipe-Encircling Excitation for Evaluation of Corrosion under Insulation.

    PubMed

    Bailey, Joseph; Long, Nicholas; Hunze, Arvid

    2017-09-28

    This work investigates an eddy current-based non-destructive testing (NDT) method to characterize corrosion of pipes under thermal insulation, one of the leading failure mechanisms for insulated pipe infrastructure. Artificial defects were machined into the pipe surface to simulate the effect of corrosion wall loss. We show that by using a giant magnetoresistance (GMR) sensor array and a high current (300 A), single sinusoidal low frequency (5-200 Hz) pipe-encircling excitation scheme it is possible to quantify wall loss defects without removing the insulation or weather shield. An analysis of the magnetic field distribution and induced currents was undertaken using the finite element method (FEM) and analytical calculations. Simple algorithms to remove spurious measured field variations not associated with defects were developed and applied. The influence of an aluminium weather shield with discontinuities and dents was ascertained and found to be small for excitation frequency values below 40 Hz. The signal dependence on the defect dimensions was analysed in detail. The excitation frequency at which the maximum field amplitude change occurred increased linearly with the depth of the defect by about 3 Hz/mm defect depth. The change in magnetic field amplitude due to defects for sensors aligned in the azimuthal and radial directions were measured and found to be linearly dependent on the defect volume between 4400-30,800 mm³ with 1.2 × 10(-3)-1.6 × 10(-3) µT/mm³. The results show that our approach is well suited for measuring wall loss defects similar to the defects from corrosion under insulation.

  12. PACER -- A fast running computer code for the calculation of short-term containment/confinement loads following coolant boundary failure. Volume 1: Code models and correlations

    SciTech Connect

    Sienicki, J.J.

    1997-06-01

    A fast running and simple computer code has been developed to calculate pressure loadings inside light water reactor containments/confinements under loss-of-coolant accident conditions. PACER was originally developed to calculate containment/confinement pressure and temperature time histories for loss-of-coolant accidents in Soviet-designed VVER reactors and is relevant to the activities of the US International Nuclear Safety Center. The code employs a multicompartment representation of the containment volume and is focused upon application to early time containment phenomena during and immediately following blowdown. Flashing from coolant release, condensation heat transfer, intercompartment transport, and engineered safety features are described using best estimate models and correlations often based upon experiment analyses. Two notable capabilities of PACER that differ from most other containment loads codes are the modeling of the rates of steam and water formation accompanying coolant release as well as the correlations for steam condensation upon structure.

  13. Application of cyclic J-integral to low cycle fatigue crack growth of Japanese carbon steel pipe

    SciTech Connect

    Miura, N.; Fujioka, T.; Kashima, K.

    1997-04-01

    Piping for LWR power plants is required to satisfy the LBB concept for postulated (not actual) defects. With this in mind, research has so far been conducted on the fatigue crack growth under cyclic loading, and on the ductile crack growth under excessive loading. It is important, however, for the evaluation of the piping structural integrity under seismic loading condition, to understand the fracture behavior under dynamic and cyclic loading conditions, that accompanies large-scale yielding. CRIEPI together with Hitachi have started a collaborative research program on dynamic and/or cyclic fracture of Japanese carbon steel (STS410) pipes in 1991. Fundamental tensile property tests were conducted to examine the effect of strain rate on tensile properties. Cracked pipe fracture tests under some loading conditions were also performed to investigate the effect of dynamic and/or cyclic loading on fracture behavior. Based on the analytical considerations for the above tests, the method to evaluate the failure life for a cracked pipe under cyclic loading was developed and verified. Cyclic J-integral was introduced to predict cyclic crack growth up to failure. This report presents the results of tensile property tests, cracked pipe fracture tests, and failure life analysis. The proposed method was applied to the cracked pipe fracture tests. The effect of dynamic and/or cyclic loading on pipe fracture was also investigated.

  14. CTS TEP thermal anomalies: Heat pipe system performance

    NASA Technical Reports Server (NTRS)

    Marcus, B. D.

    1977-01-01

    A part of the investigation is summarized of the thermal anomalies of the transmitter experiment package (TEP) on the Communications Technology Satellite (CTS) which were observed on four occasions in 1977. Specifically, the possible failure modes of the variable conductance heat pipe system (VCHPS) used for principal thermal control of the high-power traveling wave tube in the TEP are considered. Further, the investigation examines how those malfunctions may have given rise to the TEP thermal anomalies. Using CTS flight data information, ground test results, analysis conclusions, and other relevant information, the investigation concentrated on artery depriming as the most likely VCHPS failure mode. Included in the study as possible depriming mechanisms were freezing of the working fluid, Marangoni flow, and gas evolution within the arteries. The report concludes that while depriming of the heat pipe arteries is consistent with the bulk of the observed data, the factors which cause the arteries to deprime have yet to be identified.

  15. Common Cause Failure Modeling

    NASA Technical Reports Server (NTRS)

    Hark, Frank; Britton, Paul; Ring, Robert; Novack, Steven

    2015-01-01

    Space Launch System (SLS) Agenda: Objective; Key Definitions; Calculating Common Cause; Examples; Defense against Common Cause; Impact of varied Common Cause Failure (CCF) and abortability; Response Surface for various CCF Beta; Takeaways.

  16. Closure report for underground storage tank 161-R1U1 and its associated underground piping

    SciTech Connect

    Mallon, B.J.; Blake, R.G.

    1994-05-01

    Underground storage tank (UST) 161-31 R at the Lawrence Livermore National Laboratory (LLNL) was registered with the State Water Resources Control Board on June 27, 1984. UST 161-31R was subsequently renamed UST 161-R1U1 (Fig. A-1, Appendix A). UST 161-R1U1 was installed in 1976, and had a capacity of 383 gallons. This tank system consisted of a fiberglass reinforced plastic tank, approximately 320 feet of polyvinyl chloride (PVC) underground piping from Building 161, and approximately 40 feet of PVC underground piping from Building 160. The underground piping connected laboratory drains and sinks inside Buildings 160 and 161 to UST 161-R1U1. The wastewater collected in UST 161-R1U1, contained organic solvents, metals, inorganic acids, and radionuclides, most of which was produced within Building 161. On June 28, 1989, the UST 161-R1U1 piping system.around the perimeter of Building 161 failed a precision test performed by Gary Peters Enterprises (Appendix B). The 161-R1U1 tank system was removed from service after the precision test. In July 1989, additional hydrostatic tests and helium leak detection tests were performed (Appendix B) to determine the locations of the piping failures in the Building 161 piping system. The locations of the piping system failures are shown in Figure A-2 (Appendix A). On July 11, 1989, LLNL submitted an Unauthorized Release Report to Alameda County Department of Environmental Health (ACDEH), Appendix C.

  17. Radiative heat transfer estimation in pipes with various wall emissivities

    NASA Astrophysics Data System (ADS)

    Robin, Langebach; Christoph, Haberstroh

    2017-02-01

    Radiative heat transfer is usually of substantial importance in cryogenics when systems are designed and thermal budgeting is carried out. However, the contribution of pipes is commonly assumed to be comparably low since the warm and cold ends as well as their cross section are fairly small. Nevertheless, for a first assessment of each pipe rough estimates are always appreciated. In order to estimate the radiative heat transfer with traditional “paper and pencil“ methods there is only one analytical case available in literature - the case of plane-parallel plates. This case can only be used to calculate the theoretical lower and the upper asymptotic values of the radiative heat transfer, since pipe wall radiation properties are not taken into account. For this paper we investigated the radiative heat transfer estimation in pipes with various wall emissivities with the help of numerical simulations. Out of a number of calculation series we could gain an empirical extension for the used approach of plane-parallel plates. The model equation can be used to carry out enhanced paper and pencil estimations for the radiative heat transfer through pipes without demanding numerical simulations.

  18. Fracture toughness evaluations of TP304 stainless steel pipes

    SciTech Connect

    Rudland, D.L.; Brust, F.W.; Wilkowski, G.M.

    1997-02-01

    In the IPIRG-1 program, the J-R curve calculated for a 16-inch nominal diameter, Schedule 100 TP304 stainless steel (DP2-A8) surface-cracked pipe experiment (Experiment 1.3-3) was considerably lower than the quasi-static, monotonic J-R curve calculated from a C(T) specimen (A8-12a). The results from several related investigations conducted to determine the cause of the observed toughness difference are: (1) chemical analyses on sections of Pipe DP2-A8 from several surface-cracked pipe and material property specimen fracture surfaces indicate that there are two distinct heats of material within Pipe DP2-A8 that differ in chemical composition; (2) SEN(T) specimen experimental results indicate that the toughness of a surface-cracked specimen is highly dependent on the depth of the initial crack, in addition, the J-R curves from the SEN(T) specimens closely match the J-R curve from the surface-cracked pipe experiment; (3) C(T) experimental results suggest that there is a large difference in the quasi-static, monotonic toughness between the two heats of DP2-A8, as well as a toughness degradation in the lower toughness heat of material (DP2-A8II) when loaded with a dynamic, cyclic (R = {minus}0.3) loading history.

  19. Program sizes flange or pipe-tap orifice plates

    SciTech Connect

    Hogsett, J.E.

    1984-03-12

    A program has been developed for the HP-41CV programmable calculator that is designed to compute differential pressure across an orifice, gas flow through an orifice, or the orifice-plate bore for orifice plates with flange or pipe taps. It is designed to save time in extracting values from charts, tables, and graphs which are required to perform the calculations. It is based on equations and data from Spink. The program is run by inputing appropriate data via execution of a program entitled ''DATA IN,'' calculating differential pressure via program ''dH20,'' gas flow via program ''FLOW,'' and via program ''BORE.'' Flange-tap calculations are performed with FLAG 01 not set, while pipe-tap calculations are selected by setting FLAG 01.

  20. Thermal strain of pipes composed with high strength polyethylene fiber reinforced plastics at cryogenic temperatures

    SciTech Connect

    Kashima, Toshihiro; Yamanaka, Atsuhiko; Okada, Toichi

    1997-06-01

    High strength polyethylene fiber(Dyneema{reg_sign} fiber; herein after abbreviated to DF) has a large negative thermal expansion coefficient. Several kinds of pipes were prepared by means of filament winding or sheet winding method. The thermal strain or residual stress of those pipes were measured at liquid nitrogen temperature. The thermal strain was also calculated and was compared with the measured values. The circumferential thermal strain of the inner surface was found to be much different from that of outer surface. The circumferential strain changed with the ratio of inner diameter to thickness of pipes. The mean thermal strain of inner and outer surface was found to agree well with that of calculated value. It was confirmed that the negative thermal expansion can be realized even in the pipes. The design methodology of the pipes with negative thermal expansion was discussed.

  1. Plastic pipe insertion

    SciTech Connect

    Diskin, J.

    1987-05-01

    In March 1987 KPL changed all that when the utility inserted 1,000 ft of 16-in. SDR 15.5 Phillips Driscopipe 8000 pipe with a wall thickness of 1.032-in., into an abandoned 24-in. cast-iron line in downtown Kansas City. This is believed to be the largest diameter insert removal job ever done for gas distribution in the U.S. For KPL it was a natural progression from the smaller sizes used earlier. The procedure is the same, and the operation was quick and comparatively simple. Lower construction costs were the bottom line because with insert renewal there is no need to cut up the streets, a major expense in any urban pipeline work. There are other significant costs savings as well because the insert renewal construction process is faster than other techniques.

  2. Mixing in Helical Pipes

    NASA Astrophysics Data System (ADS)

    Gratton, Michael B.; Bernoff, Andrew J.

    2001-11-01

    We consider advection and diffusion of a passive scalar in a helical pipe. By assuming that the curvature and torsion are small (equivalent to small Dean number) and the Reynolds number is moderate, we can use a closed form approximation, due to Dean (1927) and Germano (1982), for the induced recirculation. We investigate the problem numerically using a split-step particle method for a variety of localized initial conditions. The problem is governed by two parameters: a nondimensional diffusion constant D (typically small), and the scaled ratio of torsion to curvature λ. At small times, the longitudinal width of the particle distribution, σ, is governed by diffusive effects (σ ∝ √Dt). At large times, Taylor diffusion dominates (σ ∝ √t/D). However, at intermediate times, a ballistic region exists where the width spreads linearly, as postulated by Mezic & Wiggins (1994). We also discuss how these various behaviors scale with the parameters D and λ.

  3. Heat pipe radiators for space. [vacuum tests

    NASA Technical Reports Server (NTRS)

    Sellers, J. P.

    1977-01-01

    An optimized flight-weight prototype fluid-header panel (heatpipe radiator system) was tested in a vacuum environment over a wide range of coolant inlet temperatures, coolant flow rates, and environmental absorbed heat fluxes. The maximum performance of the system was determined. Results are compared with earlier data obtained on a smaller fluid-header feasibility panel, and computer predictions. Freeze-thaw tests are described and the change in thaw recovery time due to the addition of a low-freezing point feeder heat pipe is evaluated. Experimental panel fin-temperature distributions are compared with calculated results.

  4. Digital holographic inspection for the inner surface of a straight pipe using current-induced multiwavelength from two laser diodes

    NASA Astrophysics Data System (ADS)

    Yokota, Masayuki; Koyama, Teppei; Kawakami, Tomoaki

    2014-10-01

    Digital holographic profilometry using multiwavelength from two laser diodes is applied to the measurement of the inner surface of a straight copper pipe and the detection of artificial defects such as holes, rust, and scratches made on the inner wall. To obtain the inner surface profile, a cone-shaped mirror (CSM) attached to a metal rod having two acrylic spacers is inserted into the pipe and illuminated by the collimated laser beam from the other open end of the pipe. The inspection of the pipe has been performed by shifting the CSM stepwise along the pipe axis. The new algorithm in which a positional misalignment of the CSM can be directly obtained from the experimental height profile can reduce the load for calculation of correcting the distorted experimental height profile. The pipe inspection has been done using the developed images of both the intensity and height profile for the inner wall of the pipe.

  5. 49 CFR 192.281 - Plastic pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint or...

  6. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic pipe...

  7. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic pipe...

  8. 49 CFR 192.281 - Plastic pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint or...

  9. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic pipe...

  10. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic pipe...

  11. 49 CFR 192.281 - Plastic pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint or...

  12. 49 CFR 192.281 - Plastic pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint or...

  13. 49 CFR 192.59 - Plastic pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic pipe...

  14. 49 CFR 192.55 - Steel pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Steel pipe. 192.55 Section 192.55 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.55 Steel pipe. (a) New steel pipe is... in accordance with paragraph (c) or (d) of this section. (b) Used steel pipe is qualified for...

  15. 49 CFR 192.55 - Steel pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Steel pipe. 192.55 Section 192.55 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.55 Steel pipe. (a) New steel pipe is... in accordance with paragraph (c) or (d) of this section. (b) Used steel pipe is qualified for...

  16. 49 CFR 192.55 - Steel pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Steel pipe. 192.55 Section 192.55 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.55 Steel pipe. (a) New steel pipe is... in accordance with paragraph (c) or (d) of this section. (b) Used steel pipe is qualified for...

  17. 49 CFR 192.55 - Steel pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Steel pipe. 192.55 Section 192.55 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.55 Steel pipe. (a) New steel pipe is... in accordance with paragraph (c) or (d) of this section. (b) Used steel pipe is qualified for...

  18. 49 CFR 192.55 - Steel pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Steel pipe. 192.55 Section 192.55 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.55 Steel pipe. (a) New steel pipe is... in accordance with paragraph (c) or (d) of this section. (b) Used steel pipe is qualified for...

  19. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Copper pipe. 192.279 Section 192.279 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Copper pipe. Copper pipe may not be threaded except that copper pipe used for joining screw fittings...

  20. 46 CFR 76.23-20 - Piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... System, Details § 76.23-20 Piping. (a) All piping, valves, and fittings shall meet the applicable requirements of subchapter F (Marine Engineering) of this chapter. (b) All piping, valves, and fittings of... the Commandant. (c) All piping, valves, fittings, and sprinkler heads shall be securely supported,...

  1. Heat pipe technology: A biblography with abstracts

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A bibliography of heat pipe research and development projects conducted during April through June 1972, is presented. The subjects discussed are: (1) general information, (2) heat pipe applications, (3) heat pipe theory, (4) design and fabrication, (5) test and operation, (6) subject and author index, and (7) heat pipe related patents.

  2. Leachate storage transport tanker loadout piping

    SciTech Connect

    Whitlock, R.W.

    1994-11-18

    This report shows the modifications to the W-025 Trench No. 31 leachate loadout discharge piping, and also the steps involved in installing the discharge piping, including dimensions and welding information. The installation of the discharge pipe should be done in accordance to current pipe installation standards. Trench No. 31 is a radioactive mixed waste land disposal facility.

  3. 46 CFR 45.133 - Air pipes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Air pipes. 45.133 Section 45.133 Shipping COAST GUARD....133 Air pipes. (a) Where an air pipe to any tank extends above the freeboard or superstructure deck— (1) The exposed part of the air pipe must be made of steel and of sufficient thickness to...

  4. 46 CFR 45.133 - Air pipes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Air pipes. 45.133 Section 45.133 Shipping COAST GUARD....133 Air pipes. (a) Where an air pipe to any tank extends above the freeboard or superstructure deck— (1) The exposed part of the air pipe must be made of steel and of sufficient thickness to...

  5. 46 CFR 45.133 - Air pipes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Air pipes. 45.133 Section 45.133 Shipping COAST GUARD....133 Air pipes. (a) Where an air pipe to any tank extends above the freeboard or superstructure deck— (1) The exposed part of the air pipe must be made of steel and of sufficient thickness to...

  6. 46 CFR 45.133 - Air pipes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Air pipes. 45.133 Section 45.133 Shipping COAST GUARD....133 Air pipes. (a) Where an air pipe to any tank extends above the freeboard or superstructure deck— (1) The exposed part of the air pipe must be made of steel and of sufficient thickness to...

  7. 46 CFR 45.133 - Air pipes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Air pipes. 45.133 Section 45.133 Shipping COAST GUARD....133 Air pipes. (a) Where an air pipe to any tank extends above the freeboard or superstructure deck— (1) The exposed part of the air pipe must be made of steel and of sufficient thickness to...

  8. 46 CFR 154.660 - Pipe welding.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... § 154.660 Pipe welding. (a) Pipe welding must meet Part 57 of this chapter. (b) Longitudinal butt welds... butt welds must meet the following: (1) Butt welds of pipes made from carbon, carbon manganese, or low... treatment. (2) Except for piping inside an independent cargo tank type A, B, or C, butt welds must be 100...

  9. 46 CFR 154.660 - Pipe welding.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... § 154.660 Pipe welding. (a) Pipe welding must meet part 57 of this chapter. (b) Longitudinal butt welds... butt welds must meet the following: (1) Butt welds of pipes made from carbon, carbon manganese, or low... treatment. (2) Except for piping inside an independent cargo tank type A, B, or C, butt welds must be 100...

  10. 46 CFR 154.660 - Pipe welding.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... § 154.660 Pipe welding. (a) Pipe welding must meet part 57 of this chapter. (b) Longitudinal butt welds... butt welds must meet the following: (1) Butt welds of pipes made from carbon, carbon manganese, or low... treatment. (2) Except for piping inside an independent cargo tank type A, B, or C, butt welds must be 100...

  11. 46 CFR 154.660 - Pipe welding.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... § 154.660 Pipe welding. (a) Pipe welding must meet part 57 of this chapter. (b) Longitudinal butt welds... butt welds must meet the following: (1) Butt welds of pipes made from carbon, carbon manganese, or low... treatment. (2) Except for piping inside an independent cargo tank type A, B, or C, butt welds must be 100...

  12. The Sacred Pipe in American Indian Religions.

    ERIC Educational Resources Information Center

    Steinmetz, Paul B.

    1984-01-01

    A bibliographic essay covers all significant literature on the Sacred Pipe among the North American tribes. Organizes over 130 references dating from 1843 to 1980 under topics such as American Indian attitudes toward the pipe, sacramental and ceremonial uses of the pipe, and the pipe as symbolic man. (JHZ)

  13. Heat pipe technology: A bibliography with abstracts

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A cumulative bibliography on heat pipe research and development projects is presented. The subjects discussed are: (1) general information, (2) heat pipe applications, (3) heat pipe theory, (4) design and fabrication, (5) testing and operation, (6) subject and author index, and (7) heat pipe related patents.

  14. Failure of the Hume-Rothery stabilization mechanism in the Ag5Li8 gamma-brass studied by first-principles FLAPW electronic structure calculations

    NASA Astrophysics Data System (ADS)

    Mizutani, U.; Asahi, R.; Sato, H.; Noritake, T.; Takeuchi, T.

    2008-07-01

    The first-principles FLAPW (full potential linearized augmented plane wave) electronic structure calculations were performed for the Ag5Li8 gamma-brass, which contains 52 atoms in a unit cell and has been known for many years as one of the most structurally complex alloy phases. The calculations were also made for its neighboring phase AgLi B2 compound. The main objective in the present work is to examine if the Ag5Li8 gamma-brass is stabilized at the particular electrons per atom ratio e/a = 21/13 in the same way as some other gamma-brasses like Cu5Zn8 and Cu9Al4, obeying the Hume-Rothery electron concentration rule. For this purpose, the e/a value for the Ag5Li8 gamma-brass as well as the AgLi B2 compound was first determined by means of the FLAPW-Fourier method we have developed. It proved that both the gamma-brass and the B2 compound possess an e/a value equal to unity instead of 21/13. Moreover, we could demonstrate why the Hume-Rothery stabilization mechanism fails for the Ag5Li8 gamma-brass and proposed a new stability mechanism, in which the unique gamma-brass structure can effectively lower the band-structure energy by forming heavily populated bonding states near the bottom of the Ag-4d band.

  15. Fatigue life prediction using multiaxial energy calculations with the mean stress effect to predict failure of linear and nonlinear elastic solids

    NASA Astrophysics Data System (ADS)

    Nagode, Marko; Šeruga, Domen

    An approach is presented that enables the calculation of elastic strain energy in linear and nonlinear elastic solids during arbitrary thermomechanical load cycles. The approach uses the simple fact that the variation of both strain and complementary energies always forms a rectangular shape in stress-strain space, hence integration is no longer required to calculate the energy. Furthermore, the approach considers the mean stress effect so that predictions of fatigue damage are more realistically representative of real-life experimental observations. By doing so, a parameter has been proposed to adjust the mean stress effect. This parameter α is based on the well-known Smith-Watson-Topper energy criterion, but allows consideration of other arbitrary mean stress effects, e.g. the Bergmann type criterion. The approach has then been incorporated into a numerical method which can be applied to uniaxial and multiaxial, proportional and non-proportional loadings to predict fatigue damage. The end result of the method is the cyclic evolution of accumulated damage. Numerical examples show how the method presented in this paper could be applied to a nonlinear elastic material.

  16. A Method Using Optical Contactless Displacement Sensors to Measure Vibration Stress of Small-Bore Piping.

    PubMed

    Maekawa, Akira; Tsuji, Takashi; Takahashi, Tsuneo; Noda, Michiyasu

    2014-02-01

    In nuclear power plants, vibration stress of piping is frequently evaluated to prevent fatigue failure. A simple and fast measurement method is attractive to evaluate many piping systems efficiently. In this study, a method to measure the vibration stress using optical contactless displacement sensors was proposed, the prototype instrument was developed, and the instrument practicality for the method was verified. In the proposed method, light emitting diodes (LEDs) were used as measurement sensors and the vibration stress was estimated by measuring the deformation geometry of the piping caused by oscillation, which was measured as the piping curvature radius. The method provided fast and simple vibration estimates for small-bore piping. Its verification and practicality were confirmed by vibration tests using a test pipe and mock-up piping. The stress measured by both the proposed method and an accurate conventional method using strain gauges were in agreement, and it was concluded that the proposed method could be used for actual plant piping systems.

  17. Heat pipe transient response approximation.

    SciTech Connect

    Reid, R. S.

    2001-01-01

    A simple and concise routine that approximates the response of an alkali metal heat pipe to changes in evaporator heat transfer rate is described. This analytically based routine is compared with data from a cylindrical heat pipe with a crescent-annular wick that undergoes gradual (quasi-steady) transitions through the viscous and condenser boundary heat transfer limits. The sonic heat transfer limit can also be incorporated into this routine for heat pipes with more closely coupled condensers. The advantages and obvious limitations of this approach are discussed. For reference, a source code listing for the approximation appears at the end of this paper.

  18. Variable conductance heat pipe technology

    NASA Technical Reports Server (NTRS)

    Marcus, B. D.; Edwards, D. K.; Anderson, W. T.

    1973-01-01

    Research and development programs in variable conductance heat pipe technology were conducted. The treatment has been comprehensive, involving theoretical and/or experimental studies in hydrostatics, hydrodynamics, heat transfer into and out of the pipe, fluid selection, and materials compatibility, in addition to the principal subject of variable conductance control techniques. Efforts were not limited to analytical work and laboratory experimentation, but extended to the development, fabrication and test of spacecraft hardware, culminating in the successful flight of the Ames Heat Pipe Experiment on the OAO-C spacecraft.

  19. Hydrological connectivity of soil pipes

    NASA Astrophysics Data System (ADS)

    Holden, J.

    2003-04-01

    Natural soil pipes are common in many parts of the world and particularly in blanket peat uplands yet there are problems in finding and defining soil pipe networks which are often located deep within the peat. Pipeflow can contribute a large proportion of runoff to the river systems in these upland environments and may significantly influence catchment sediment and solute yield. Ground penetrating radar (GPR) technology has recently been developed for non-destructive identification and mapping of soil pipes in peat catchments. While GPR can identify subsurface cavities, it cannot alone determine hydrological connectivity between one cavity and another. This poster presents results from an experiment to test the ability of GPR to establish hydrological connectivity between pipes through use of a tracer solution. Tracers such as sodium chloride were injected at a constant rate into an open pipe cavity. The GPR was moved across the test area downslope. The resultant radargrams were analysed and significantly increased reflectance was observed from a selection of cavities downslope. It was thus possible to determine hydrological connectivity of soil pipes within a dense pipe network across a hillslope without ground disturbance. In addition, tracers were added to the peat surface upslope of known pipe networks. It was possible to then trace the movement of water across and through the hillslope by using GPR to establish the connectivity of a range of flowpaths. Often pipe networks were supplied with water from overland flow entering through cracks and openings where the soil pipe was near the peat surface. Downslope, pipeflow contributed not only directly to streamflow but also to overland flow and near-surface throughflow on the hillslope. The same water that was within a pipe network at four metres depth could become near-surface throughflow outside of the pipe network a few metres down slope. These data allow the first three-dimensional picture of subsurface

  20. Asymmetric Collapse of LOS Pipe.

    DTIC Science & Technology

    1980-05-26

    models that were used to simulate a LOS pipe . Still, the jet was eliminated in a Pinex model with a helical ribbon of polyolefin on the inside surface of...Target from the Pinex Model 71 with Poly Spiral in Experiment LS-3 .41 b l [ SECTION 1 *. INTRODUCTION 1.1 BACKGROUND Line-of-sight (LOS) pipes are...distance. 3.5.7 Simulation of Pinex Pipe . As shown in the photo- graphs provided in Figures 37 and 38, the Pinex-Standard Model and Pinex-Polyolefin Spiral

  1. Plastic pipe at road crossings

    SciTech Connect

    Not Available

    1988-12-01

    This article reports how a North Carolina company is using high-density polyethylene pipe at state road crossings as an insulator to keep the outer casing pipe from touching the inner gas carrier pipeline. This prevents static charges that can cause corrosion, gas leaks and other problems on the pipeline. It enables the company to meet requirements of the North Carolina Department of Transportation that large-diameter steel gas pipelines crossing beneath state highways be enclosed in another steel pipe for protection against damage.

  2. Light pipe - design for efficiency

    SciTech Connect

    Hockey, S.N.

    1985-08-01

    The high cost and availability of materials which are clear enough to transmit light without absorption has limited the idea of piping large-scale quantities of light. The light pipe uses the principle of Total Internal Reflection, with the light guided by very accurate prisms. The transmission of light directed into the end of a Light Pipe at an angle of less than 27.6 degrees is theoretically 100% efficient. The author describes its uses and advantages for lighting offices, cold storage areas, difficult access and hazardous areas, and for solar lighting. Future directions will be to improve the economics and accuracy of the technology. 4 references, 2 figures.

  3. Loop Heat Pipe Startup Behaviors

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2016-01-01

    A loop heat pipe must start successfully before it can commence its service. The startup transient represents one of the most complex phenomena in the loop heat pipe operation. This paper discusses various aspects of loop heat pipe startup behaviors. Topics include the four startup scenarios, the initial fluid distribution between the evaporator and reservoir that determines the startup scenario, factors that affect the fluid distribution between the evaporator and reservoir, difficulties encountered during the low power startup, and methods to enhance the startup success. Also addressed are the pressure spike and pressure surge during the startup transient, and repeated cycles of loop startup and shutdown under certain conditions.

  4. Analyzing failures: The problems and the solutions

    SciTech Connect

    Goel, V.S.

    1985-01-01

    This book presents the papers given at a conference on fatigue, corrosion cracking, fracture mechanics, and failure analysis. Topics considered at the conference included materials failure prevention at the National Bureau of Standards, the failure analysis of a liquid propane gas cylinder, a vent header crack at the Hatch-2 reactor, the application of fracture mechanics to pipeline failure analysis, the microstructural examination of fuel rods subjected to a simulated loss of coolant accident, and a heavy section stainless steel-316 pipe and its weldment with reduced susceptibility to embrittlement for advanced fossil plants.

  5. Heat pipe life and processing study

    NASA Technical Reports Server (NTRS)

    Antoniuk, D.; Luedke, E. E.

    1979-01-01

    The merit of adding water to the reflux charge in chemically and solvent cleaned aluminum/slab wick/ammonia heat pipes was evaluated. The effect of gas in the performance of three heat pipe thermal control systems was found significant in simple heat pipes, less significant in a modified simple heat pipe model with a short wickless pipe section. Use of gas data for the worst and best heat pipes of the matrix in a variable conductance heat pipe model showed a 3 C increase in the source temperature at full on condition after 20 and 246 years, respectively.

  6. Pressure surge reflector for pipe type cable system

    SciTech Connect

    Chu, H.; El Badaly, H.A.; Ghafurian, R. ); Aabo, T.; Ringlee, R.R.; Williams, J.A. ); Melcher, J. )

    1990-04-01

    This paper describes work performed on the development and testing of a pressure surge reflector, designed to reduce the pressure seen at potheads during an electrical failure in a pipe type cable system. The reflector is designed to protect the potheads from failing due to the pressure surge that may be large enough to fracture the porcelain, particularly when the electrical failure is physically close to the pothead. Test results show that the prototype reflector will lower the pressure significantly, bringing the pressure surge below the factory pressure test level for standard potheads.

  7. Heat-Transfer Coupling For Heat Pipes

    NASA Technical Reports Server (NTRS)

    Nesmith, Bill J.

    1991-01-01

    Proposed welded heat-transfer coupling joins set of heat pipes to thermoelectric converter. Design avoids difficult brazing operation. Includes pair of mating flanged cups. Upper cup integral part of housing of thermoelectric converter, while lower cup integral part of plate supporting filled heat pipes. Heat pipes prefilled. Heat of welding applied around periphery of coupling, far enough from heat pipes so it would not degrade working fluid or create excessive vapor pressure in the pipes.

  8. Intermediate Temperature Water Heat Pipe Tests

    NASA Technical Reports Server (NTRS)

    Devarakonda, Angirasa; Xiong, Daxi; Beach, Duane E.

    2004-01-01

    Heat pipes are among the most promising technologies for space radiator systems. Water heat pipes are explored in the intermediate temperature range of 400 to above 500 K. The thermodynamic and thermo-physical properties of water are reviewed in this temperature range. Test Data are reported for a copper-water heat pipe. The heat pipe was tested under different orientations. Water heat pipes show promise in this temperature range.Fabrication and testing issues are being addressed.

  9. Intermediate Temperature Water Heat Pipe Tests

    NASA Technical Reports Server (NTRS)

    Devarakonda, Angirasa; Xiong, Da-Xi; Beach, Duane E.

    2005-01-01

    Heat pipes are among the most promising technologies for space radiator systems. Water heat pipes are explored in the intermediate temperature range of 400 to above 500 K. The thermodynamic and thermo-physical properties of water are reviewed in this temperature range. Test data are reported for a copper-water heat pipe. The heat pipe was tested under different orientations. Water heat pipes show promise in this temperature range. Fabrication and testing issues are being addressed.

  10. B Plant process piping replacement feasibility study

    SciTech Connect

    Howden, G.F.

    1996-02-07

    Reports on the feasibility of replacing existing embedded process piping with new more corrosion resistant piping between cells and between cells and a hot pipe trench of a Hanford Site style canyon facility. Provides concepts for replacement piping installation, and use of robotics to replace the use of the canyon crane as the primary means of performing/supporting facility modifications (eg, cell lining, pipe replacement, equipment reinstallation) and operational maintenenace.

  11. Fiberglass Reinforced Piping for Shipboard Systems

    DTIC Science & Technology

    1976-07-01

    B16.5 far flanges. Piping is gal- vanized. Thickness corresponds to standard weight. Diameters are 8" and 10”. Joininq. The piping system is welded ...critical, standard elbows are used in place of bends. Supports. Pipe hangers are made of U-bolts through angle iron supports welded directly to the ship...and 30" . Joining. The piping system is welded wherever possible, including at bulkhead penetrations. Spuds are welded into the pipe to form tee

  12. 46 CFR 56.10-5 - Pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Pipe. 56.10-5 Section 56.10-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Components § 56.10-5 Pipe. (a) General. Pipe and tubing shall be selected as described in table 56.60-1(a). (b) Ferrous pipe. ASTM Specification A 53 ...

  13. Loop Heat Pipe Startup Behaviors

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2014-01-01

    A loop heat pipe must start successfully before it can commence its service. The start-up transient represents one of the most complex phenomena in the loop heat pipe operation. This paper discusses various aspects of loop heat pipe start-up behaviors. Topics include the four start-up scenarios, the initial fluid distribution between the evaporator and reservoir that determines the start-up scenario, factors that affect the fluid distribution between the evaporator and reservoir, difficulties encountered during the low power start-up, and methods to enhance the start-up success. Also addressed are the thermodynamic constraint between the evaporator and reservoir in the loop heat pipe operation, the superheat requirement for nucleate boiling, pressure spike and pressure surge during the start-up transient, and repeated cycles of loop start-up andshutdown under certain conditions.

  14. Heat pipe radiators for space

    NASA Technical Reports Server (NTRS)

    Sellers, J. P.

    1976-01-01

    Analysis of the data heat pipe radiator systems tested in both vacuum and ambient environments was continued. The systems included (1) a feasibility VCHP header heat-pipe panel, (2) the same panel reworked to eliminate the VCHP feature and referred to as the feasibility fluid header panel, and (3) an optimized flight-weight fluid header panel termed the 'prototype.' A description of freeze-thaw thermal vacuum tests conducted on the feasibility VCHP was included. In addition, the results of ambient tests made on the feasibility fluid header are presented, including a comparison with analytical results. A thermal model of a fluid header heat pipe radiator was constructed and a computer program written. The program was used to make a comparison of the VCHP and fluid-header concepts for both single and multiple panel applications. The computer program was also employed for a parametric study, including optimum feeder heat pipe spacing, of the prototype fluid header.

  15. Method for casting polyethylene pipe

    NASA Technical Reports Server (NTRS)

    Elam, R. M., Jr.

    1973-01-01

    Short lengths of 7-cm ID polyethylene pipe are cast in a mold which has a core made of room-temperature-vulcanizable (RTV) silicone. Core expands during casting and shrinks on cooling to allow for contraction of the polyethylene.

  16. Light pipes for LED measurements

    NASA Technical Reports Server (NTRS)

    Floyd, S. R.; Thomas, E. F., Jr.

    1976-01-01

    Light pipe directly couples LED optical output to single detector. Small area detector measures total optical output of diode. Technique eliminates thermal measurement problems and channels optical output to remote detector.

  17. Corrugated pipe adhesive applicator apparatus

    DOEpatents

    Shirey, R.A.

    1983-06-14

    Apparatus for coating selected portions of the troughs of a corrugated pipe with an adhesive includes a support disposed within the pipe with a reservoir containing the adhesive disposed on the support. A pump, including a spout, is utilized for supplying the adhesive from the reservoir to a trough of the pipe. A rotatable applicator is supported on the support and contacts the trough of the pipe. The applicator itself is sized so as to fit within the trough, and contacts the adhesive in the trough and spreads the adhesive in the trough upon rotation. A trough shield, supported by the support and disposed in the path of rotation of the applicator, is utilized to prevent the applicator from contacting selected portions of the trough. A locator head is also disposed on the support and provides a way for aligning the spout, the applicator, and the trough shield with the trough. 4 figs.

  18. Corrugated pipe adhesive applicator apparatus

    DOEpatents

    Shirey, Ray A.

    1983-06-14

    Apparatus for coating selected portions of the troughs of a corrugated pipe within an adhesive includes a support disposed within the pipe with a reservoir containing the adhesive disposed on the support. A pump, including a spout, is utilized for supplying the adhesive from the reservoir to a trough of the pipe. A rotatable applicator is supported on the support and contacts the trough of the pipe. The applicator itself is sized so as to fit within the trough, and contacts the adhesive in the trough and spreads the adhesive in the trough upon rotation. A trough shield, supported by the support and disposed in the path of rotation of the applicator, is utilized to prevent the applicator from contacting selected portions of the trough. A locator head is also disposed on the support and provides a way for aligning the spout, the applicator, and the trough shield with the trough.

  19. Light pipes for LED measurements

    NASA Technical Reports Server (NTRS)

    Floyd, S. R.; Thomas, E. F., Jr.

    1976-01-01

    Light pipe directly couples LED optical output to single detector. Small area detector measures total optical output of diode. Technique eliminates thermal measurement problems and channels optical output to remote detector.

  20. D0 Solenoid Upgrade Project: Solenoid Insulatiing Vacuum Vessels; Relief Path Capacity Calculation

    SciTech Connect

    Rucinski, R.; Bell, D.; /Fermilab

    1993-05-26

    This engineering note documents the calculations done to determine the relief capacity of the solenoid vacuum pumping line. The calculations were done by David Bell, a co-op student from the University of Wisconsin. The calculations are attached. The conclusion is that the vacuum pumping line has a venting capacity of 129 g/s warm helium or 298 g/s warm nitrogen. Both of these capacities are much larger than the expected operating mass flow rates of the liquid helium (5 to 15 g/s) or liquid nitrogen (2 or 3 g/s) circuits. The calculations assume the solenoid vacuum vessel is at 3 psig and the relief plate is set at 1.5 psig. Additional calculations were done to prove that the venting capacity of the vacuum pumping line exceeded flowrates due to a failure mode. These calculations are attached. Since the system is not finalized, (pipe sizes not determined, components sized...) the calculations were done by first picking reasonable line sizes based on known allowed pressure drops in the system and then doing a maximum delivery rate calculation if a line was completely severed in the vacuum space of the solenoid/control dewar. The numbers from these calculations say that failure mode flow rates are 80 g/s liquid helium or 80 g/s liquid nitrogen. Both these values are less than the capacity of the relief line. In the five months since the (12/92 Dave Bell) calculations were done, some changes occured to the relief path. The most notable is that the radiation shield is now considered to be 6.625-inch O.D. instead of 6.00-inch used in the venting calculation. This change would tend to lower the capacity numbers. Another change was that for about half the venting path the chimney vacuum shell size was increased to 10-inch pipe. This change tends to increase the capacity numbers which were done assuming 8-inch pipe. These changes taken together probably offset each other or make the capacity numbers better. In either case, since the margin of safety is large, the

  1. Kimberlite Wall Rock Fragmentation: Venetia K08 Pipe Development

    NASA Astrophysics Data System (ADS)

    Barnett, W.; Kurszlaukis, S.; Tait, M.; Dirks, P.

    2009-05-01

    Volcanic systems impose powerful disrupting forces on the country rock into which they intrude. The nature of the induced brittle deformation or fragmentation can be characteristic of the volcanic processes ongoing within the volcanic system, but are most typically partially removed or obscured by repeated, overprinting volcanic activity in mature pipes. Incompletely evolved pipes may therefore provide important evidence for the types and stages of wall rock fragmentation, and mechanical processes responsible for the fragmentation. Evidence for preserved stages of fragmentation is presented from a detailed study of the K08 pipe within the Cambrian Venetia kimberlite cluster, South Africa. This paper investigates the growth history of the K08 pipe and the mechanics of pipe development based on observations in the pit, drill core and thin sections, from geochemical analyses, particle size distribution analyses, and 3D modeling. Present open pit exposures of the K08 pipe comprise greater than 90% mega-breccia of country rock clasts (gneiss and schist) with <10% intruding, coherent kimberlite. Drill core shows that below about 225 m the CRB includes increasing quantities of kimberlite. The breccia clasts are angular, clast-supported with void or carbonate cement between the clasts. Average clast sizes define sub-horizontal layers tens of metres thick across the pipe. Structural and textural observations indicate the presence of zones of re-fragmentation or zones of brittle shearing. Breccia textural studies and fractal statistics on particle size distributions (PSD) is used to quantify sheared and non- sheared breccia zones. The calculated energy required to form the non-sheared breccia PSD implies an explosive early stage of fragmentation that pre-conditions the rock mass. The pre-conditioning would have been caused by explosions that are either phreatic or phreatomagmatic in nature. The explosions are likely to have been centered on a dyke, or pulses of preceding

  2. Mapping Temperatures On Heat Pipes

    NASA Technical Reports Server (NTRS)

    Gunnerson, Fred S.; Thorncroft, Glen E.

    1993-01-01

    Paints containing thermochromic liquid crystals (TLC's) used to map temperatures on heat pipes and thermosyphons. Color of thermally sensitive TLC coat changes reversibly upon heating or cooling. Each distinct color indicates particular temperature. Transient and steady-state isotherms become visible as colored bands. Positions and movements of bands yield information about startup transients, steady-state operation, cooler regions containing noncondensible gas, and other phenomena relevant to performance of heat pipe.

  3. Heat Pipe Thermal Conditioning Panel

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.

    1973-01-01

    The technology involved in designing and fabricating a heat pipe thermal conditioning panel to satisfy a broad range of thermal control system requirements on NASA spacecraft is discussed. The design specifications were developed for a 30 by 30 inch heat pipe panel. The fundamental constraint was a maximum of 15 gradient from source to sink at 300 watts input and a flux density of 2 watts per square inch. The results of the performance tests conducted on the panel are analyzed.

  4. Piping Inelastic Fracture Mechanics Analysis.

    DTIC Science & Technology

    1980-06-30

    DOCUMENTATION PAGE BEFORE COMPLETING FORM I. REPORT NUMBER 12. GOVT ACCESSION NO. S. RECIPIENT’S CATALOG NUMBER NUREG /CR 1119 4259 NRL Memorandum Report _4259...Steel Piping of Boiling Water Reactor Plants," US Nuclear Regulatory Commission, NUREG -75/067, October, 1975. 2. "Investigation and Evaluation of...Stress-Corrosion Cracking in Piping of Light-Water Reactor Plants," US Nuclear Regulatory Commission, NUREG -0531, February, 1979. 3. F.J. Witt, W.H

  5. [Prevalence of hidden renal failure calculated through formulas on the degree of renal function in hypertense patients over 60 referred to out-patients for blood pressure monitoring].

    PubMed

    Pozuelos Estrada, Gerónimo; Molina Martínez, Luis; Romero Perera, Juan José; Díaz Herrera, Natalio; Cañón Barroso, Lourdes; Buitrago Ramírez, Francisco

    2007-05-01

    To validate the Cockroft-Gault and the abbreviated Modification of Diet in Renal Disease (MDRD) formulas in a hypertense population aged over 60 and with blood pressure monitored in out-patients. To evaluate the prevalence of various stages of hidden chronic kidney disease in this population. Descriptive study of validation of diagnostic tests. Urban primary care centre. A total of 113 patients over 60 (53.8% female) with hypertension and no history of chronic kidney disease, on whom blood pressure could be monitored in a 24-hour session. Calculation of the glomerular filtration rate. Validity parameters of diagnostic tests. Renal clearance estimated in the Cockroft-Gault and MDRD equations was similar (77.9 mL/min and 76.9 mL/min, respectively). There was 37.3% prevalence of chronic kidney disease, using the Cockroft-Gault equation; and 27.0%, using the MDRD. The degree of agreement between the two equations was excellent in classifying patients with stage-2 chronic kidney disease (kappa index =0.9) and it was acceptable for stage-3 (kappa index =0.5). In both equations, validity indexes were acceptable for the presence of microalbuminuria as a manifestation of renal damage. There is a high prevalence of hidden chronic kidney disease in the hypertense population over 60 years old. Glomerular filtration should be determined systematically in these patients, even when their plasma creatinine figures are normal.

  6. Flight data analysis and further development of variable-conductance heat pipes

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.; Edwards, D. K.; Luedke, E. E.

    1976-01-01

    The work focuses on the mathematical modeling of three critical mechanisms of heat-pipe operation: (1) the effect that excess liquid has on heat-pipe performance; (2) the calculation of the dryout limit of circumferential grooves; (3) an efficient mathematical model for the calculation of the viscous-inertial interaction in the vapor flow. These mathematical models are incorporated in the computer program GRADE II, which is described.

  7. Simplified dispersion relationships for fluid-dominated axisymmetric wave motion in buried fluid-filled pipes

    NASA Astrophysics Data System (ADS)

    Gao, Yan; Sui, Fusheng; Muggleton, Jennifer M.; Yang, Jun

    2016-08-01

    The dispersion characteristics of axisymmetric (n=0) waves offer a way to gain physical insight into the low-frequency vibrational behaviour of underground pipe systems. Whilst these can be found in the literature, they are generally calculated numerically. Coupled equations of motion for the n=0 waves that propagate in a buried fluid-filled pipe are presented in this paper and, from this, an analytical solution is developed for the fluid-dominated (s=1) wavenumber. The effect of the frictional stress at the pipe-soil interface on the dispersion behaviour of the s=1 wave is characterised by adopting a soil loading matrix. Overall, the fluid loading has a greater effect on the propagation wavespeed compared with the soil loading: for metal pipes, the effect of soil loading is negligible; for plastic pipes, however, simply neglecting the effect of soil loading can lead to a considerable underestimation in the calculation of the wavespeed. The wave attenuation increases significantly at higher frequencies regardless of pipe material resulting from the added damping due to radiation into the soil. Theoretical predictions of the s=1 wavenumber are compared with experimental data measured on an MDPE water pipe. The degree of agreement between prediction and experiment makes clear that, although the wavespeed is only slightly affected by the presence of the frictional stress, the frictional stress at the pipe-soil interface needs to be appropriately taken into account for attenuation predictions.

  8. LARGE-BORE PIPE DECONTAMINATION

    SciTech Connect

    M.A. Ebadian

    1999-01-01

    The decontamination and characterization of large-bore pipe is difficult because of the various geometries and diameters of pipe and its different material types. A robust decontamination system must be capable of adapting to different pipe diameters (project scope is 6 inches to 24 inches), cleaning surfaces with various surface conditions and material types (i.e., painted, rusted, carbon steel, or stainless steel), and be cost-effective to operate and maintain. The characterization system must be capable of handling the different pipe parameters and detecting contamination on the inside and outside surfaces. It must also operate in a cost-effective manner. Current technology options do not provide a robust system to meet these objectives. The purpose of this project is to verify the need for this technology through determining quantities of pipe available for decontamination (completed FY97), perform a technology screening process to select technologies for decontamination (completed FY97) and characterization (completed FY98), perform treatability studies to collect required performance data (completed FY97), and design and fabricate a prototype system to decontaminate and characterize the internal and external surfaces of large-bore pipe. A field mobile system capable of performing decontamination and characterization operations will be the main deliverable for this project. A summary of activities completed during FY97 is provided to understand the project development and implementation process.

  9. Heat pipe turbine vane cooling

    SciTech Connect

    Langston, L.; Faghri, A.

    1995-10-01

    The applicability of using heat pipe principles to cool gas turbine vanes is addressed in this beginning program. This innovative concept involves fitting out the vane interior as a heat pipe and extending the vane into an adjacent heat sink, thus transferring the vane incident heat transfer through the heat pipe to heat sink. This design provides an extremely high heat transfer rate and an uniform temperature along the vane due to the internal change of phase of the heat pipe working fluid. Furthermore, this technology can also eliminate hot spots at the vane leading and trailing edges and increase the vane life by preventing thermal fatigue cracking. There is also the possibility of requiring no bleed air from the compressor, and therefore eliminating engine performance losses resulting from the diversion of compressor discharge air. Significant improvement in gas turbine performance can be achieved by using heat pipe technology in place of conventional air cooled vanes. A detailed numerical analysis of a heat pipe vane will be made and an experimental model will be designed in the first year of this new program.

  10. Heat pipe turbine vane cooling

    SciTech Connect

    Langston, L.; Faghri, A.

    1995-12-31

    The applicability of using heat pipe principles to cool gas turbine vanes is addressed in this beginning program. This innovative concept involves fitting out the vane interior as a heat pipe and extending the vane into an adjacent heat sink, thus transferring the vane incident heat transfer through the heat pipe to heat sink. This design provides an extremely high heat transfer rate and a uniform temperature along the vane due to the internal change of phase of the heat pipe working fluid. Furthermore, this technology can also eliminate hot spots at the vane leading and trailing edges and increase the vane life by preventing thermal fatigue cracking. There is also the possibility of requiring no bleed air from the compressor, and therefore eliminating engine performance losses resulting from the diversion of compressor discharge air. Significant improvement in gas turbine performance can be achieved by using heat pipe technology in place of conventional air cooled vanes. A detailed numerical analysis of a heat pipe vane will be made and an experimental model will be designed in the first year of this new program.

  11. Automated internal pipe cutting device

    DOEpatents

    Godlewski, William J.; Haffke, Gary S.; Purvis, Dale; Bashar, Ronald W.; Jones, Stewart D.; Moretti, Jr., Henry; Pimentel, James

    2003-01-21

    The invention is a remotely controlled internal pipe cutting device primarily used for cutting pipes where the outside of the pipe is inaccessible at the line where the cut is to be made. The device includes an axial ram within a rotational cylinder which is enclosed in a housing. The housing is adapted for attachment to an open end of the pipe and for supporting the ram and cylinder in cantilever fashion within the pipe. A radially movable cutter, preferably a plasma arc torch, is attached to the distal end of the ram. A drive mechanism, containing motors and mechanical hardware for operating the ram and cylinder, is attached to the proximal end of the housing. The ram and cylinder provide for moving the cutter axially and circumferentially, and a cable assembly attached to a remote motor provide for the movement of the cutter radially, within the pipe. The control system can be adjusted and operated remotely to control the position and movement of the cutter to obtain the desired cut. The control system can also provide automatic standoff control for a plasma arc torch.

  12. Pipe weld crown removal device

    SciTech Connect

    Sword, C.K.; Sette, P.J.

    1992-11-24

    A device is provided for grinding down the crown of a pipe weld joining aligned pipe sections so that the weld is substantially flush with the pipe sections joined by the weld. The device includes a cage assembly comprising a pair of spaced cage rings adapted to be mounted for rotation on the respective pipe sections on opposite sides of the weld, a plurality of grinding wheels, supported by the cage assembly for grinding down the crown of the weld, and a plurality of support shafts, each extending longitudinally along the joined pipe sections, parallel thereto, for individually mounting respective grinding wheels. Each end of the support shafts is mounted for rotation in a bearing assembly housed within a radially directed opening in a corresponding one of the cage rings so as to provide radial movement of the associated shaft, and thus of the associated grinding wheel, towards and away from the weld. A first drive sprocket provides rotation of the cage assembly around the pipe sections while a second drive unit, driven by a common motor, provides rotation of the grinding wheels. 2 figs.

  13. Pipe weld crown removal device

    SciTech Connect

    Sword, C.K.; Sette, P.J.

    1991-12-31

    This invention is comprised of a device that provides for grinding down the crown of a pipe weld joining aligned pipe sections so that the weld is substantially flush with the pipe sections joined by the weld. The device includes a cage assembly comprising a pair of spaced cage rings adapted to be mounted for rotation on the respective pipe sections on opposite sides of the weld, a plurality of grinding wheels, supported by the cage assembly for grinding down the crown of the weld, and a plurality of support shafts, each extending longitudinally along the joined pipe sections, parallel thereto, for individually mounting respective grinding wheels. Each end of the support shafts is mounted for rotation in a bearing assembly housed within a radially directed opening in a corresponding one of the cage rings so as to provide radial movement of the associated shaft, and thus of the associated grinding wheel, towards and away from the weld. A first drive sprocket provides rotation of the cage assembly around the pipe sections while a second drive unit, driven by a common motor, provides rotation of the grinding wheels.

  14. Pipe weld crown removal device

    DOEpatents

    Sword, Charles K.; Sette, Primo J.

    1992-01-01

    A device is provided for grinding down the crown of a pipe weld joining aligned pipe sections so that the weld is substantially flush with the pipe sections joined by the weld. The device includes a cage assembly comprising a pair of spaced cage rings adapted to be mounted for rotation on the respective pipe sections on opposite sides of the weld, a plurality of grinding wheels, supported by the cage assembly for grinding down the crown of the weld, and a plurality of support shafts, each extending longitudinally along the joined pipe sections, parallel thereto, for individually mounting respective grinding wheels. Each end of the support shafts is mounted for rotation in a bearing assembly housed within a radially directed opening in a corresponding one of the cage rings so as to provide radial movement of the associated shaft, and thus of the associated grinding wheel, towards and away from the weld. A first drive sprocket provides rotation of the cage assembly around the pipe sections while a second drive unit, driven by a common motor, provides rotation of the grinding wheels.

  15. Heat pipe cooled power magnetics

    NASA Technical Reports Server (NTRS)

    Chester, M. S.

    1979-01-01

    A high frequency, high power, low specific weight (0.57 kg/kW) transformer developed for space use was redesigned with heat pipe cooling allowing both a reduction in weight and a lower internal temperature rise. The specific weight of the heat pipe cooled transformer was reduced to 0.4 kg/kW and the highest winding temperature rise was reduced from 40 C to 20 C in spite of 10 watts additional loss. The design loss/weight tradeoff was 18 W/kg. Additionally, allowing the same 40 C winding temperature rise as in the original design, the KVA rating is increased to 4.2 KVA, demonstrating a specific weight of 0.28 kg/kW with the internal loss increased by 50W. This space environment tested heat pipe cooled design performed as well electrically as the original conventional design, thus demonstrating the advantages of heat pipes integrated into a high power, high voltage magnetic. Another heat pipe cooled magnetic, a 3.7 kW, 20A input filter inductor was designed, developed, built, tested, and described. The heat pipe cooled magnetics are designed to be Earth operated in any orientation.

  16. Design and fabrication of polymer-concrete-lined pipe for testing in geothermal-energy processes. Final report

    SciTech Connect

    Kaeding, A.O.

    1981-12-01

    A specific polymer-concrete formulation was applied as a steel pipe liner in response to a need for durable, economical materials for use in contact with high temperature geothermal brine. Processes are described for centrifugally applying the liner to straight pipe, for casting the liner in pipe fittings, and for closure of field joints. Physical properties of the liner materials were measured. Compressive strengths of up to 165.8 MPa (24,045 psi) and splitting tensile strengths of 23.5 MPa (3408 psi) were measured at ambient temperature. Compressive strengths of 24 MPa (3490 psi) and splitting tensile strengths of 2.5 MPa (366 psi) were measured at about 150/sup 0/C (302/sup 0/F). A full-scale production plant is described which would be capable of producing about 950 m (3120 ft) of lined 305-mm-diam (12 in.) pipe per day. Capital cost of the plant is estimated to be about $8.6 million with a calculated return on investment of 15.4%. Cost of piping a geothermal plant with PC and PC-lined steel pipe is calculated to be $1.21 million, which compares favorably with a similar plant piped with alloy steel piping at a cost of $1.33 million. Life-cycle cost analysis indicates that the cost of PC-lined steel pipe would be 82% of that of carbon steel pipe over a 20-year plant operating life.

  17. Effect of corrosion and stress-corrosion cracking on pipe integrity and remaining life

    SciTech Connect

    Jaske, C.E.; Beavers, J.A.

    1996-07-01

    Process piping is often exposed to corrosive fluids. During service, such exposure may cause localized corrosion or stress-corrosion cracking that affects structural integrity. This paper presents a model that quantifies the effect of localized corrosion and stress-corrosion cracking on pipe failure stress. The model is an extension of those that have been developed for oil and gas pipelines. It accounts for both axial and hoop stress. Cracks are modeled using inelastic fracture mechanics. Both flow-stress and fracture-toughness dependent failure modes are addressed. Corrosion and crack-growth rates are used to predict remaining service life.

  18. Analysis to predict the shapes of growing stress corrosion cracks in BWR piping welds

    SciTech Connect

    McNaughton, W.P.; Egan, G.R.; Beaupre, G.S.; Aboim, C.A.

    1982-05-01

    A model has been developed to predict the shape during growth and lifetime to failure for stress corrosion cracks in boiling water reactor (BWR) piping. The primary emphasis for this project was on large diameter recirculation piping. The results of sensitivity studies performed with the model are presented in this report. It was found, for the ranges of variables examined, that the primary influence on crack shape is stress distribution. Somewhat smaller effects on crack shape growth result from the absolute stress magnitude, changes in growth kinetics and changes in initial flaw geometry. The manner in which each of the variables affects lifetime to failure is also examined.

  19. Piping inspection round robin

    SciTech Connect

    Heasler, P.G.; Doctor, S.R.

    1996-04-01

    The piping inspection round robin was conducted in 1981 at the Pacific Northwest National Laboratory (PNNL) to quantify the capability of ultrasonics for inservice inspection and to address some aspects of reliability for this type of nondestructive evaluation (NDE). The round robin measured the crack detection capabilities of seven field inspection teams who employed procedures that met or exceeded the 1977 edition through the 1978 addenda of the American Society of Mechanical Engineers (ASME) Section 11 Code requirements. Three different types of materials were employed in the study (cast stainless steel, clad ferritic, and wrought stainless steel), and two different types of flaws were implanted into the specimens (intergranular stress corrosion cracks (IGSCCs) and thermal fatigue cracks (TFCs)). When considering near-side inspection, far-side inspection, and false call rate, the overall performance was found to be best in clad ferritic, less effective in wrought stainless steel and the worst in cast stainless steel. Depth sizing performance showed little correlation with the true crack depths.

  20. Fabrication Flaw Density and Distribution in Piping Weldments

    SciTech Connect

    Doctor, Steven R.

    2009-09-01

    The U.S. Nuclear Regulatory Commission supported the Pacific Northwest National Laboratory (PNNL) to develop empirical data on the density and distribution of fabrication flaws in nuclear reactor components. These data are needed to support probabilistic fracture mechanics calculations and studies on component structural integrity. PNNL performed nondestructive examination inspections and destructive testing on archived piping welds to determine the fabrication flaw size and distribution characteristics of the flaws in nuclear power plant piping weldments. Eight different processes and product forms in piping weldments were studied including wrought stainless steel and dissimilar metal weldments. Parametric analysis using an exponential fit was performed on the data. Results were created as a function of the through-wall size of the fabrication flaws as well as the length distribution. The results are compared and contrasted with those developed for reactor pressure vessel processes and product forms. The most significant findings were that the density of fabrication flaws versus through-wall size was higher in piping weldments than that for the reactor pressure vessel weldments, and the density of fabrication flaws versus through-wall size in both reactor pressure vessel weld repairs and piping weldments were greater than the density in the original weldments. Curves showing these distributions are presented.

  1. Heat pipe radiation cooling of advanced hypersonic propulsion system components

    NASA Technical Reports Server (NTRS)

    Martin, R. A.; Keddy, M.; Merrigan, M. A.; Silverstein, C. C.

    1991-01-01

    Heat transfer, heat pipe, and system studies were performed to assess the newly proposed heat pipe radiation cooling (HPRC) concept. With an HPRC system, heat is removed from the ramburner and nozzle of a hypersonic aircraft engine by a surrounding, high-temperature, heat pipe nacelle structure, transported to nearby external surfaces, and rejected to the environment by thermal radiation. With HPRC, the Mach number range available for using hydrocarbon fuels for aircraft operation extends into the Mach 4 to Mach 6 range, up from the current limit of about Mach 4. Heat transfer studies using a newly developed HPRC computer code determine cooling system and ramburner and nozzle temperatures, heat loads, and weights for a representative combined-cycle engine cruising at Mach 5 at 80,000 ft altitude. Heat pipe heat transport calculations, using the Los Alamos code HTPIPE, reveal that adequate heat trasport capability is available using molybdenum-lithium heat pipe technology. Results show that the HPRC system radiator area is limited in size to the ramburner-nozzle region of the engine nacelle; reasonable system weights are expected; hot section temperatures are consistent with advanced structural materials development goals; and system impact on engine performance is minimal.

  2. Ultrasonic isolation of buried pipes

    NASA Astrophysics Data System (ADS)

    Leinov, Eli; Lowe, Michael J. S.; Cawley, Peter

    2016-02-01

    Long-range guided wave testing (GWT) is used routinely for the monitoring and detection of corrosion defects in above ground pipelines. The GWT test range in buried, coated pipelines is greatly reduced compared to above ground configurations due to energy leakage into the embedding soil. In this paper, the effect of pipe coatings on the guided wave attenuation is investigated with the aim of increasing test ranges for buried pipelines. The attenuation of the T(0,1) and L(0,2) guided wave modes is measured using a full-scale experimental apparatus in a fusion-bonded epoxy (FBE)-coated 8 in. pipe, buried in loose and compacted sand. Tests are performed over a frequency range typically used in GWT of 10-35 kHz and compared with model predictions. It is shown that the application of a low impedance coating between the FBE layer and the sand effectively decouples the influence of the sand on the ultrasound leakage from the buried pipe. Ultrasonic isolation of a buried pipe is demonstrated by coating the pipe with a Polyethylene (PE)-foam layer that has a smaller impedance than both the pipe and sand, and has the ability to withstand the overburden load from the sand. The measured attenuation in the buried PE-foam-FBE-coated pipe is found to be substantially reduced, in the range of 0.3-1.2 dB m-1 for loose and compacted sand conditions, compared to measured attenuation of 1.7-4.7 dB m-1 in the buried FBE-coated pipe without the PE-foam. The acoustic properties of the PE-foam are measured independently using ultrasonic interferometry and incorporated into model predictions of guided wave propagation in buried coated pipe. Good agreement is found between the experimental measurements and model predictions. The attenuation exhibits periodic peaks in the frequency domain corresponding to the through-thickness resonance frequencies of the coating layer. The large reduction in guided wave attenuation for PE-coated pipes would lead to greatly increased GWT test ranges; such

  3. NEP heat pipe radiators. [Nuclear Electric Propulsion

    NASA Technical Reports Server (NTRS)

    Ernst, D. M.

    1979-01-01

    This paper covers improvements of heat pipe radiators for the thermionic NEP design. Liquid metal heat pipes are suitable as spacecraft radiator elements because of high thermal conductance, low mass and reliability, but the NEP thermionic system design was too large and difficult to fabricate. The current integral collector-radiator design consisting of several layers of thermionic converters, the annular-tangential collector heat pipe, the radiator heat pipe, and the transition zone designed to minimize the temperature difference between the collector heat pipe and radiator heat pipe are described. Finally, the design of micrometeoroid armor protection and the fabrication of the stainless steel annular heat pipe with a tangential arm are discussed, and it is concluded that the heat rejection system for the thermionic NEP system is well advanced, but the collector-radiator heat pipe transition and the 8 to 10 m radiator heat pipe with two bends require evaluation.

  4. NEP heat pipe radiators. [Nuclear Electric Propulsion

    NASA Technical Reports Server (NTRS)

    Ernst, D. M.

    1979-01-01

    This paper covers improvements of heat pipe radiators for the thermionic NEP design. Liquid metal heat pipes are suitable as spacecraft radiator elements because of high thermal conductance, low mass and reliability, but the NEP thermionic system design was too large and difficult to fabricate. The current integral collector-radiator design consisting of several layers of thermionic converters, the annular-tangential collector heat pipe, the radiator heat pipe, and the transition zone designed to minimize the temperature difference between the collector heat pipe and radiator heat pipe are described. Finally, the design of micrometeoroid armor protection and the fabrication of the stainless steel annular heat pipe with a tangential arm are discussed, and it is concluded that the heat rejection system for the thermionic NEP system is well advanced, but the collector-radiator heat pipe transition and the 8 to 10 m radiator heat pipe with two bends require evaluation.

  5. Random walk approach for dispersive transport in pipe networks

    NASA Astrophysics Data System (ADS)

    Sämann, Robert; Graf, Thomas; Neuweiler, Insa

    2016-04-01

    Keywords: particle transport, random walk, pipe, network, HYSTEM-EXTAN, OpenGeoSys After heavy pluvial events in urban areas the available drainage system may be undersized at peak flows (Fuchs, 2013). Consequently, rainwater in the pipe network is likely to spill out through manholes. The presence of hazardous contaminants in the pipe drainage system represents a potential risk to humans especially when the contaminated drainage water reaches the land surface. Real-time forecasting of contaminants in the drainage system needs a quick calculation. Numerical models to predict the fate of contaminants are usually based on finite volume methods. Those are not applicable here because of their volume averaging elements. Thus, a more efficient method is preferable, which is independent from spatial discretization. In the present study, a particle-based method is chosen to calculate transport paths and spatial distribution of contaminants within a pipe network. A random walk method for particles in turbulent flow in partially filled pipes has been developed. Different approaches for in-pipe-mixing and node-mixing with respect to the geometry in a drainage network are shown. A comparison of dispersive behavior and calculation time is given to find the fastest model. The HYSTEM-EXTRAN (itwh, 2002) model is used to provide hydrodynamic conditions in the pipe network according to surface runoff scenarios in order to real-time predict contaminant transport in an urban pipe network system. The newly developed particle-based model will later be coupled to the subsurface flow model OpenGeoSys (Kolditz et al., 2012). References: Fuchs, L. (2013). Gefährdungsanalyse zur Überflutungsvorsorge kommunaler Entwässerungssysteme. Sanierung und Anpassung von Entwässerungssystemen-Alternde Infrastruktur und Klimawandel, Österreichischer Wasser-und Abfallwirtschaftsverband, Wien, ISBN, 978-3. itwh (2002). Modellbeschreibung, Institut für technisch-wissenschaftliche Hydrologie Gmb

  6. Acme jumper pipe system for coke-oven charging

    SciTech Connect

    Medved, P.D.; Thomas, H.

    1996-08-01

    Acme Steel has operated larry cars with an attached jumper pipe since 1977 and had been able to meet the State Implementation Plan (SIP). With the advent of the Clean Air Act (CAA), Acme considered that it could not meet these new standards without modifications to the jumper pipe system. Several drop sleeve modifications, boot seal materials and configurations were tested that resulted in limited success in improving the boot seal life. These modifications showed that the Clean Air Act standards could be met, but it would be cost prohibitive to continue to operate in this manner. The company decided to install an off-car jumper pipe system which uses a traveling U-tube for connection to the assist oven through an additional hole in the roof of each oven. Temperature related failures of drop sleeve seals were eliminated. The off-car jumper pipe is a more efficient gas connection to the assist oven and enables the company to meet the Clean Air Act charging requirements in a cost effective manner.

  7. Ultrasonic Guided Wave Focus Inspection Potential of Bare and Coated Pipes

    NASA Astrophysics Data System (ADS)

    Mu, J.; Hua, J.; Rose, J. L.

    2010-02-01

    Ultrasonic guided waves in elastic bare pipes are studied from a theoretical point of view. Dispersion curves of both axisymmetric and non-axisymmetric waves are presented. The parameters of 4-channel focusing are calculated by a phased array focusing algorithm. Experimentally four defects are detected in a cased pipe inspection. The defect probability of detection is highly improved by applying the phased array focusing technique. Guided wave dispersion curves in coated pipes are calculated using a 1-D Semi-Analytical Finite Element (SAFE) technique. This theoretically driven hybrid SAFE method has perfectly tackled the guided wave problem in coated pipes, including dispersion curves (phase velocity dispersion curves and attenuation dispersion curves) and wave structures. The time delays and amplitudes of the 8-channel focusing in an 8 in sch40 coated pipe are calculated by the SAFE algorithm and input to the FEM simulation in ABAQUS®. Focusing performance is improved up to 67% by applying the coated pipe parameters compared with the bare pipe parameters.

  8. Mathematical Modeling of Loop Heat Pipes

    NASA Technical Reports Server (NTRS)

    Kaya, Tarik; Ku, Jentung; Hoang, Triem T.; Cheung, Mark L.

    1998-01-01

    The primary focus of this study is to model steady-state performance of a Loop Heat Pipe (LHP). The mathematical model is based on the steady-state energy balance equations at each component of the LHP. The heat exchange between each LHP component and the surrounding is taken into account. Both convection and radiation environments are modeled. The loop operating temperature is calculated as a function of the applied power at a given loop condition. Experimental validation of the model is attempted by using two different LHP designs. The mathematical model is tested at different sink temperatures and at different elevations of the loop. Tbc comparison of the calculations and experimental results showed very good agreement (within 3%). This method proved to be a useful tool in studying steady-state LHP performance characteristics.

  9. Heat Rejection Systems Utilizing Composites and Heat Pipes: Design and Performance Testing

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Beach, Duane E.; Sanzi, James L.

    2007-01-01

    Polymer matrix composites offer the promise of reducing the mass and increasing the performance of future heat rejection systems. With lifetimes for heat rejection systems reaching a decade or more in a micrometeoroid environment, use of multiple heat pipes for fault tolerant design is compelling. The combination of polymer matrix composites and heat pipes is of particular interest for heat rejection systems operating on the lunar surface. A technology development effort is under way to study the performance of two radiator demonstration units manufactured with different polymer matrix composite face sheet resin and bonding adhesives, along with different titanium-water heat pipe designs. Common to the two radiator demonstration units is the use of high thermal conductivity fibers in the face sheets and high thermal conductivity graphite saddles within a light weight aluminum honeycomb core. Testing of the radiator demonstration units included thermal vacuum exposure and thermal vacuum exposure with a simulated heat pipe failure. Steady state performance data were obtained at different operating temperatures to identify heat transfer and thermal resistance characteristics. Heat pipe failure was simulated by removing the input power from an individual heat pipe in order to identify the diminished performance characteristics of the entire panel after a micrometeoroid strike. Freeze-thaw performance was also of interest. This paper presents a summary of the two radiator demonstration units manufactured to support this technology development effort along with the thermal performance characteristics obtained to date. Future work will also be discussed.

  10. Turbine-Driven Pipe-Cleaning Brush

    NASA Technical Reports Server (NTRS)

    Werlink, Rudy J.; Rowell, David E.

    1994-01-01

    Simple pipe-cleaning device includes small turbine wheel axially connected, by standoff, to circular brush. Turbine wheel turns on hub bearing attached to end of upstream cable. Turbine-and-brush assembly inserted in pipe with cable trailing upstream and brush facing downstream. Water or cleaning solution pumped through pipe. Cable held at upstream end, so it holds turbine and brush in pipe at location to be cleaned. Flow in pipe turns turbine, which turns wheel, producing desired cleaning action. In addition to brushing action, device provides even mixing of cleaning solution in pipe.

  11. Magnetic refrigeration apparatus with heat pipes

    DOEpatents

    Barclay, John A.; Prenger, Jr., F. Coyne

    1987-01-01

    A magnetic refrigerator operating in the 4 to 20 K range utilizes heat pipes to transfer heat to and from the magnetic material at the appropriate points during the material's movement. In one embodiment circular disks of magnetic material can be interleaved with the ends of the heat pipes. In another embodiment a mass of magnetic material reciprocatingly moves between the end of the heat pipe of pipes that transmits heat from the object of cooling to the magnetic material and the end of the heat pipe or pipes that transmits heat from the magnetic material to a heat sink.

  12. Magnetic refrigeration apparatus with heat pipes

    DOEpatents

    Barclay, J.A.; Prenger, F.C. Jr.

    1985-10-25

    A magnetic refrigerator operating in the 4 to 20 K range utilizes heat pipes to transfer heat to and from the magnetic material at the appropriate points during the material's movement. In one embodiment circular disks of magnetic material can be interleaved with the ends of the heat pipes. In another embodiment a mass of magnetic material reciprocatingly moves between the end of the heat pipe or pipes that transmits heat from the object of cooling to the magnetic material and the end of the heat pipe or pipes that transmits heat from the magnetic material to a heat sink.

  13. Development of a glass polymer composite sewer pipe from waste glass. Final report

    SciTech Connect

    Rayfiel, R.; Kukacka, L.E.

    1980-02-01

    A range of polymer-aggregate composites for applications in industry which appear to be economically attractive and contribute to energy conservation were developed at BNL. Waste glass is the aggregate in one such material, which is called glass-polymer-composite (GPC). This report assays the economics and durability of GPC in piping for storm drains and sewers. The properties of the pipe are compared statistically with the requirements of industrial specifications. These establish the raw materials requirements. The capital and operating costs for producing pipe are then estimated. Using published sales values for competing materials, the return on investment is calculated for two cases. The ultimate energy requirement of the raw materials in GPC is compared with the corresponding requirement for vitrified clay pipe. The strengths of GPC, reinforced concrete, vitrified clay and asbestos cement pipe are compared after extended exposure to various media. The status of process and product development is reviewed and recommendations are made for future work.

  14. A design method of axially grooved heat pipes embedded in equipment panel for communication satellite

    NASA Astrophysics Data System (ADS)

    Miyasaka, Akihiro; Nakajima, Katsuhiko

    A calculation method of the maximum heat load for an axially grooved heat pipe which is embedded in a honeycomb sandwich panel with multipoint heating is developed by considering the estimation of heat flux rate along the heat pipe. A thermal mathematical model for the panel is also used to estimate the net heat input to the heat pipe. The maximum heat loads predicted for the heat pipe embedded in the panel show good agreement with the data obtained from tests which has been performed in a vacuum chamber. A minimum weight design method for rectangular grooved heat pipes which satisfied heat transport capabilities required are also proposed as a result of this study.

  15. Piping Effects on the Heat Transfer Characteristics of an Evacuated Tubular Solar Collector

    NASA Astrophysics Data System (ADS)

    Saito, Akio; Miyazawa, Nobuyuki

    Effects on the heat transfer characteristics of a vacuum type solar collector system by connecting piping sections were discussed experimentally and analytically. Experiments were carried out under various solar radiation intensities, water flow rates, inlet water temperatures, periods of the solar intensity fluctuations and the insulating specifications for the piping section. Simulations were also performed by the finite difference calculations which were proved to agree well with the experimental results. As the results, it was found that the slight water temperature decrease at the entrance of the collector, by connecting the piping section, did not affect the collector efficiency seriously, although the whole collector plate temperature was lowered. It was also found that the heat loss from the collector plate to the pipe was negligible, if the piping section was insulated properly, and the effects appeared only in the limited edge sections of the collector plate, lowering the plate temperature.

  16. Numerical simulation of flow characteristic in three-dimensional bend pipes

    NASA Astrophysics Data System (ADS)

    Wang, T.; Tu, S.; Dong, D.

    2010-03-01

    Variety of pipes with different types of layout is widely used in enterprise. Flow resistance and turbulence is increased by irrational layout of the pipes and flow conditions, and even the pipe system vibration will occur induced probably by fluid disturbance. In this paper, three typical bend pipes in three-dimension are analyzed from pressure loss and streamline by numerical simulation. The straight and bend section of the pipe is generated and meshed by the hexahedral elements. The quality of meshes is good, and the grid cells are about 300,000. Calculation shows that the first type with the inlet and outlet in opposite direction in one plane has the least resistance coefficient. Therefore, adopting plain layout may be the best choice of the three types mentioned in the paper.

  17. Effects of toughness anisotropy and combined tension, torsion, and bending loads on fracture behavior of ferritic nuclear pipe

    SciTech Connect

    Mohan, R.; Marshall, C.; Ghadiali, N.; Wilkowski, G.

    1997-04-01

    This paper summarizes work on angled through-wall-crack initiation and combined loading effects on ferritic nuclear pipe performed as part of the Nuclear Regulatory Commission`s research program entitled {open_quotes}Short Cracks In Piping an Piping Welds{close_quotes}. The reader is referred to Reference 1 for details of the experiments and analyses conducted as part of this program. The major impetus for this work stemmed from the observation that initially circumferentially oriented cracks in carbon steel pipes exhibited a high tendency to grow at a different angle when the cracked pipes were subjected to bending or bending plus pressure loads. This failure mode was little understood, and the effect of angled crack grown from an initially circumferential crack raised questions about how cracks in a piping system subjected to combined loading with torsional stresses would behave. There were three major efforts undertaken in this study. The first involved a literature review to assess the causes of toughness anisotropy in ferritic pipes and to develop strength and toughness data as a function of angle from the circumferential plane. The second effort was an attempt to develop a screening criterion based on toughness anisotropy and to compare this screening criterion with experimental pipe fracture data. The third and more significant effort involved finite element analyses to examine why cracks grow at an angle and what is the effect of combined loads with torsional stresses on a circumferentially cracked pipe. These three efforts are summarized.

  18. Volatile pipe prices ahead

    SciTech Connect

    Perkins, C.

    1988-01-01

    Over the last 10 years, prices for oilfield casing and tubing have shot up and down like a roller coaster. Average pipe prices went up 80 percent in the 1979-81 drilling boom. They dropped 50 percent in the 1982-83 period, only to recover 20 percent in 1984-85. The collapse of crude prices caused another 30 percent drop in 1986. Since they bottomed out in August of that year, prices have come up by 60 percent. The key question: ''What lies ahead.'' The short answer: ''Probably more of the same''. This article looks at what has caused price fluctuations of such magnitude and volatility over the past several years to assess the outlook for 1988 and beyond. The author says we are not on the brink of a severe OCTG shortage of any sort, though there may be some very localized spot shortages in terms of deliverability and price. There is likely to be some build up of tubular inventory among supply houses wary of losing regular customers to those with adequate inventories. The characteristic first-of-the-year dip in the active rig count will supplement a slight inventory building, as will an expected increase in imports. The bottomline impact for the wellsite is there is little chance for substantial price increases until the third or fourth quarter of this year. Even then, a considerable jump in utilization would be needed and most analysts are predicting the rig count to slowly rise to about the 1500-plus range for the fourth quarter.

  19. Strain Modal Analysis of Small and Light Pipes Using Distributed Fibre Bragg Grating Sensors.

    PubMed

    Huang, Jun; Zhou, Zude; Zhang, Lin; Chen, Juntao; Ji, Chunqian; Pham, Duc Truong

    2016-09-25

    Vibration fatigue failure is a critical problem of hydraulic pipes under severe working conditions. Strain modal testing of small and light pipes is a good option for dynamic characteristic evaluation, structural health monitoring and damage identification. Unique features such as small size, light weight, and high multiplexing capability enable Fibre Bragg Grating (FBG) sensors to measure structural dynamic responses where sensor size and placement are critical. In this paper, experimental strain modal analysis of pipes using distributed FBG sensors ispresented. Strain modal analysis and parameter identification methods are introduced. Experimental strain modal testing and finite element analysis for a cantilever pipe have been carried out. The analysis results indicate that the natural frequencies and strain mode shapes of the tested pipe acquired by FBG sensors are in good agreement with the results obtained by a reference accelerometer and simulation outputs. The strain modal parameters of a hydraulic pipe were obtained by the proposed strain modal testing method. FBG sensors have been shown to be useful in the experimental strain modal analysis of small and light pipes in mechanical, aeronautic and aerospace applications.

  20. Strain Modal Analysis of Small and Light Pipes Using Distributed Fibre Bragg Grating Sensors

    PubMed Central

    Huang, Jun; Zhou, Zude; Zhang, Lin; Chen, Juntao; Ji, Chunqian; Pham, Duc Truong

    2016-01-01

    Vibration fatigue failure is a critical problem of hydraulic pipes under severe working conditions. Strain modal testing of small and light pipes is a good option for dynamic characteristic evaluation, structural health monitoring and damage identification. Unique features such as small size, light weight, and high multiplexing capability enable Fibre Bragg Grating (FBG) sensors to measure structural dynamic responses where sensor size and placement are critical. In this paper, experimental strain modal analysis of pipes using distributed FBG sensors ispresented. Strain modal analysis and parameter identification methods are introduced. Experimental strain modal testing and finite element analysis for a cantilever pipe have been carried out. The analysis results indicate that the natural frequencies and strain mode shapes of the tested pipe acquired by FBG sensors are in good agreement with the results obtained by a reference accelerometer and simulation outputs. The strain modal parameters of a hydraulic pipe were obtained by the proposed strain modal testing method. FBG sensors have been shown to be useful in the experimental strain modal analysis of small and light pipes in mechanical, aeronautic and aerospace applications. PMID:27681728

  1. Experimental and analytical study of water pipe's rupture for damage identification purposes

    NASA Astrophysics Data System (ADS)

    Papakonstantinou, Konstantinos G.; Shinozuka, Masanobu; Beikae, Mohsen

    2011-04-01

    A malfunction, local damage or sudden pipe break of a pipeline system can trigger significant flow variations. As shown in the paper, pressure variations and pipe vibrations are two strongly correlated parameters. A sudden change in the flow velocity and pressure of a pipeline system can induce pipe vibrations. Thus, based on acceleration data, a rapid detection and localization of a possible damage may be carried out by inexpensive, nonintrusive monitoring techniques. To illustrate this approach, an experiment on a single pipe was conducted in the laboratory. Pressure gauges and accelerometers were installed and their correlation was checked during an artificially created transient flow. The experimental findings validated the correlation between the parameters. The interaction between pressure variations and pipe vibrations was also theoretically justified. The developed analytical model explains the connection among flow pressure, velocity, pressure wave propagation and pipe vibration. The proposed method provides a rapid, efficient and practical way to identify and locate sudden failures of a pipeline system and sets firm foundations for the development and implementation of an advanced, new generation Supervisory Control and Data Acquisition (SCADA) system for continuous health monitoring of pipe networks.

  2. Pipe crawler with extendable legs

    DOEpatents

    Zollinger, William T.

    1992-01-01

    A pipe crawler for moving through a pipe in inchworm fashion having front and rear leg assemblies separated by air cylinders to increase and decrease the spacing between assemblies. Each leg of the four legs of an assembly is moved between a wall-engaging, extended position and a retracted position by a separate air cylinder. The air cylinders of the leg assemblies are preferably arranged in pairs of oppositely directed cylinders with no pair lying in the same axial plane as another pair. Therefore, the cylinders can be as long a leg assembly is wide and the crawler can crawl through sections of pipes where the diameter is twice that of other sections. The crawler carries a valving system, a manifold to distribute air supplied by a single umbilical air hose to the various air cylinders in a sequence controlled electrically by a controller. The crawler also utilizes a rolling mechanism, casters in this case, to reduce friction between the crawler and pipe wall thereby further extending the range of the pipe crawler.

  3. Pipe crawler with extendable legs

    DOEpatents

    Zollinger, W.T.

    1992-06-16

    A pipe crawler for moving through a pipe in inchworm fashion having front and rear leg assemblies separated by air cylinders to increase and decrease the spacing between assemblies. Each leg of the four legs of an assembly is moved between a wall-engaging, extended position and a retracted position by a separate air cylinder. The air cylinders of the leg assemblies are preferably arranged in pairs of oppositely directed cylinders with no pair lying in the same axial plane as another pair. Therefore, the cylinders can be as long as a leg assembly is wide and the crawler can crawl through sections of pipes where the diameter is twice that of other sections. The crawler carries a valving system, a manifold to distribute air supplied by a single umbilical air hose to the various air cylinders in a sequence controlled electrically by a controller. The crawler also utilizes a rolling mechanism, casters in this case, to reduce friction between the crawler and pipe wall thereby further extending the range of the pipe crawler. 8 figs.

  4. Flexible ultrasonic pipe inspection apparatus

    DOEpatents

    Jenkins, C.F.; Howard, B.D.

    1998-06-23

    A flexible, modular ultrasonic pipe inspection apparatus, comprises a flexible, hollow shaft that carries a plurality of modules, including at least one rotatable ultrasonic transducer, a motor/gear unit, and a position/signal encoder. The modules are connected by flexible knuckle joints that allow each module of the apparatus to change its relative orientation with respect to a neighboring module, while the shaft protects electrical wiring from kinking or buckling while the apparatus moves around a tight corner. The apparatus is moved through a pipe by any suitable means, including a tether or drawstring attached to the nose or tail, differential hydraulic pressure, or a pipe pig. The rotational speed of the ultrasonic transducer and the forward velocity of the apparatus are coordinated so that the beam sweeps out the entire interior surface of the pipe, enabling the operator to accurately assess the condition of the pipe wall and determine whether or not leak-prone corrosion damage is present. 7 figs.

  5. Centrally activated pipe snubbing system

    DOEpatents

    Cawley, William E.

    1985-01-01

    An electromechanical pipe snubbing system and an electromechanical pipe snubber. In the system, each pipe snubber, in a set of pipe snubbers, has an electromechanical mechanism to lock and unlock the snubber. A sensor, such as a seismometer, measures a quantity related to making a snubber locking or unlocking decision. A control device makes an electrical connection between a power supply and each snubber's electromechanical mechanism to simultaneously lock each snubber when the sensor measurement indicates a snubber locking condition. The control device breaks the connection to simultaneously unlock each snubber when the sensor measurement indicates a snubber unlocking condition. In the snubber, one end of the shaft slides within a bore in one end of a housing. The other end of the shaft is rotatably attached to a pipe; the other end of the housing is rotatively attached to a wall. The snubber's electromechanical mechanism locks the slidable end of the shaft to the housing and unlocks that end from the housing. The electromechanical mechanism permits remote testing and lockup status indication for each snubber.

  6. Repairing pipes on the fly

    SciTech Connect

    1997-04-01

    When piping develops leaks, the natural instinct is to shut the process down, purge the lines and call in maintenance crews to make the repairs. There is, however, an alternative: on-the-fly repairs. Through the use of specialized tools, equipment and technicians, shut-off valves can be installed and leaks repaired without interrupting production. The split sleeve offers one of the simpler approaches to on-the-fly repairs. Two half cylinders with inside diameter slightly larger than the outside diameter slightly larger than the outside diameter of the pipe to be repaired are slipped over the latter some distance form the leak and loosely bolted together. The cylinder is then slid over the leaking area and the bolts tightened. Gaskets inside the half cylinders provide the needed seal between the pipe and the cylinder. Installing a shut-off valve in an operating pipeline requires much more specialized equipment and skills than does repairing a leak with a split sleeve. A device available from International Piping Services Co. allows a trained crew to isolate a section of pipe, drill out the isolated portion, install a blocking valve and then remove the isolation system--all while continuing to operate the pipeline at temperatures to 700 F and pressures to 700 psi. But Herb Porter, CEO of Ipsco, cautions that unlike the repairing leaks with a split sleeve, installing a blocking valve on-the-fly always demands the services of a highly trained crew.

  7. Flight data analysis and further development of variable-conductance heat pipes. [for aircraft control

    NASA Technical Reports Server (NTRS)

    Enginer, J. E.; Luedke, E. E.; Wanous, D. J.

    1976-01-01

    Continuing efforts in large gains in heat-pipe performance are reported. It was found that gas-controlled variable-conductance heat pipes can perform reliably for long periods in space and effectively provide temperature stabilization for spacecraft electronics. A solution was formulated that allows the control gas to vent through arterial heat-pipe walls, thus eliminating the problem of arterial failure under load, due to trace impurities of noncondensable gas trapped in an arterial bubble during priming. This solution functions well in zero gravity. Another solution was found that allows priming at a much lower fluid charge. A heat pipe with high capacity, with close temperature control of the heat source and independent of large variations in sink temperature was fabricated.

  8. Plastic collapse solutions for girth-welded pipes and welded sleeve assemblies with cracks

    SciTech Connect

    Yi-Wang, Yong; Mohr, W.; Sun, Xin

    1997-03-03

    The work described in this report is to provide plastic collapse solutions for girth-welded pipes and welded sleeve assemblies with circumferential cracks. The first phase of this project involved nonlinear finite element analysis (FEA) of pipes with circumferential cracks of different size. Provisional plastic collapse solutions were developed based on a large number of analyses. The second phase of this project involved full-scale tests of two 16-in. (406.4-mm) X60 pipes with circumferential cracks at the fillet weld toe of full-encirclement sleeves. The pipes were loaded by internal pressure and lateral four-point bending until burst at the crack locations. The loads at failure were recorded and compared with the provisional solutions developed in Phase 1 of the project. Other commonly used plastic collapse solutions were examined in both Phases 1 and 2 to determine their relative degree of conservatism.

  9. Graphitic corrosion -- Don`t forget about buried cast iron pipes

    SciTech Connect

    Freeman, S.R.

    1999-08-01

    Graphitic corrosion is a form of de-alloying or selective leaching that occurs in cast iron material. This corrosion mechanism is unique to gray cast irons and is caused by the graphitic matrix present. The graphite is cathodic to the iron matrix. Exposure to an electrolyte results in leaching of the iron matrix, leaving behind a porous mass of graphite flakes. Graphite corrosion often occurs in buried gray cast iron pipes, although exposure to an aqueous environment is all that is necessary for the de-alloying to occur. The process of de-alloying in cast iron typically is long-term, taking several years to occur. In fact, many cases of graphitic corrosion-caused failure in cast iron piping occur in piping that has been in service for 50 years or more. Mechanical testing to determine the tensile strength of cast iron can provide information regarding the remaining strength of the pipe.

  10. Gait failure.

    PubMed

    Sudarsky, L

    1987-11-01

    Gait failure is a common presentation in the Emergency Department, and one that may herald an acute neurologic episode. This article reviews the mechanisms of gait failure, some of their causes, and the appropriate examination techniques for determining possible diagnoses.

  11. Respiratory Failure

    MedlinePlus

    Respiratory failure happens when not enough oxygen passes from your lungs into your blood. Your body's organs, ... brain, need oxygen-rich blood to work well. Respiratory failure also can happen if your lungs can' ...

  12. Failure Analysis of Epoxy-Lined Asbestos-Cement Pipe.

    DTIC Science & Technology

    1981-12-01

    hardness, and stability when exposed samples were thoroughly dried at 212OF (100 0C) to acidic, alkaline, and neutral liquid submersion. overnight in...more pliable. Residual stresses usually cause Infra- Red Analysis deformation of the plastic. which releives the stresses. Detailed analyses were...conducted using a Fourier Transform Infra- Red Spectrometer (FTIR). This The degree or extent of swelling depends on a method allows precise, well-defined

  13. Mixing at double-Tee junctions with unequal pipe sizes in ...

    EPA Pesticide Factsheets

    Pipe flow mixing with various solute concentrations and flow rates at pipe junctions is investigated. The degree of mixing affects the spread of contaminants in a water distribution system. Many studies have been conducted on the mixing at the cross junctions. Yet a few have focused on double-Tee junctions of unequal pipe sizes. To investigate the solute mixing at double-Tee junctions with unequal pipe sizes, a series of experiments were conducted in a turbulent regime (Re=12500–50000) with different Reynolds number ratios and connecting pipe lengths. It is shown that dimensionless outlet concentrations depended on mixing mechanism at the impinging interface of junctions. Junction with a larger pipe size ratio is associated with more complete mixing. The inlet Reynolds number ratio affects mixing more strongly than the outlet Reynolds number ratio. Furthermore, the dimensionless connecting pipe length in a double-Tee played an important and complicated role in the flow mixing. Based on these results, two-dimensional isopleth maps were developed for the calculation of normalized north outlet concentration. This journal article is to communicate the research results on pipe juncture mixing, a widespread and important phenomena in distribution system water quality analysis. The research outcome improves EPANET modeling capability for safe water supplies. In addition, the research is one of the outputs from the EPA-MOST bilateral cooperative research Project #1

  14. Influence of pipe material and surfaces on sulfide related odor and corrosion in sewers.

    PubMed

    Nielsen, Asbjørn Haaning; Vollertsen, Jes; Jensen, Henriette Stokbro; Wium-Andersen, Tove; Hvitved-Jacobsen, Thorkild

    2008-09-01

    Hydrogen sulfide oxidation on sewer pipe surfaces was investigated in a pilot scale experimental setup. The experiments were aimed at replicating conditions in a gravity sewer located immediately downstream of a force main where sulfide related concrete corrosion and odor is often observed. During the experiments, hydrogen sulfide gas was injected intermittently into the headspace of partially filled concrete and plastic (PVC and HDPE) sewer pipes in concentrations of approximately 1,000 ppm(v). Between each injection, the hydrogen sulfide concentration was monitored while it decreased because of adsorption and subsequent oxidation on the pipe surfaces. The experiments showed that the rate of hydrogen sulfide oxidation was approximately two orders of magnitude faster on the concrete pipe surfaces than on the plastic pipe surfaces. Removal of the layer of reaction (corrosion) products from the concrete pipes was found to reduce the rate of hydrogen sulfide oxidation significantly. However, the rate of sulfide oxidation was restored to its background level within 10-20 days. A similar treatment had no observable effect on hydrogen sulfide removal in the plastic pipe reactors. The experimental results were used to model hydrogen sulfide oxidation under field conditions. This showed that the gas-phase hydrogen sulfide concentration in concrete sewers would typically amount to a few percent of the equilibrium concentration calculated from Henry's law. In the plastic pipe sewers, significantly higher concentrations were predicted because of the slower adsorption and oxidation kinetics on such surfaces.

  15. Updated pipe break analysis for Advanced Neutron Source Reactor conceptual design

    SciTech Connect

    Wendel, M.W.; Chen, N.C.J.; Yoder, G.L.

    1994-04-01

    The Advanced Neutron Source Reactor (ANSR) is a research reactor to be built at the Oak Ridge National Laboratory that will supply the highest continuous neutron flux levels of any reactor in the world. It uses plate-type fuel with high-mass-flux and highly subcooled heavy water as the primary coolant. The Conceptual Safety Analysis for the ANSR was completed in June 1992. The thermal-hydraulic pipe-break safety analysis (performed with a specialized version of RELAP5/MOD3) focused primarily on double-ended guillotine breaks of the primary piping and some core-damage mitigation options for such an event. Smaller, instantaneous pipe breaks in the cold- and hot-leg piping were also analyzed to a limited extent. Since the initial analysis for the conceptual design was completed, several important changes to the RELAP5 input model have been made reflecting improvements in the fuel grading and changes in the elevation of the primary coolant pumps. Also, a new philosophy for pipe-break safety analysis (similar to that adopted for the New Production Reactor) accentuates instantaneous, limited flow area pipe-break accidents in addition to finite-opening-time, double-ended guillotine breaks of the major coolant piping. This paper discloses the results of the most recent instantaneous pipe-break calculations.

  16. Heart Failure

    MedlinePlus

    Heart failure is a condition in which the heart can't pump enough blood to meet the body's needs. Heart failure does not mean that your heart has stopped ... Tiredness and shortness of breath Common causes of heart failure are coronary artery disease, high blood pressure and ...

  17. The Worker Exposure Failure Modes and Effects Analysis

    SciTech Connect

    Cadwallader, L.C.

    2005-05-15

    The Worker Exposure Failure Modes and Effects Analysis (WE-FMEA) is a new approach to quantitatively evaluate worker risks from possible failures of co-located equipment in the complex environment of a magnetic or inertial fusion experiment. For next-step experiments such as the International Thermonuclear Experimental Reactor (ITER) or the National Ignition Facility (NIF), the systems and equipment will be larger, handle more throughput or power, and will, in general, be more robust than past experiments. These systems and equipment are necessary to operate the machine, but the rooms are congested with equipment, piping, and cables, which poses a new level of hazard for workers who will perform hands-on maintenance. The WE-FMEA systematically analyzes the nearby equipment and the work environment for equipment failure or inherent hazards, and then develops exposure scenarios. Once identified, the exposure scenarios are evaluated for the worker hazards and quantitative worker risk is calculated. Then risk scenarios are quantitatively compared to existing statistical data on worker injuries; high-risk scenarios can be identified and addressed in more detail to determine the proper means to reduce, mitigate, or protect against the hazard. The WE-FMEA approach is described and a cooling system maintenance example is given.

  18. Flat heat pipe design, construction, and analysis

    SciTech Connect

    Voegler, G.; Boughey, B.; Cerza, M.; Lindler, K.W.

    1999-08-02

    This paper details the design, construction and partial analysis of a low temperature flat heat pipe in order to determine the feasibility of implementing flat heat pipes into thermophotovoltaic (TPV) energy conversion systems.

  19. Heat pipe design handbook, part 1

    NASA Technical Reports Server (NTRS)

    Skrabek, E. A.

    1972-01-01

    The development and characteristics of heat pipes are examined. The subjects discussed are: (1) principles of operation, (2) heat pipe theory, (3) pressure gradient effects, (4) variable conductance, (5) design procedure, and (6) performance limit evaluation.

  20. 46 CFR 193.15-15 - Piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... fittings shall have a bursting pressure of not less than 6,000 pounds per square inch. (b) All piping, in... by blowing out the piping with air at a pressure of at least 100 pounds per square inch....