Science.gov

Sample records for air flow rates

  1. Position paper -- Tank ventilation system design air flow rates

    SciTech Connect

    Goolsby, G.K.

    1995-01-04

    The purpose of this paper is to document a project position on required ventilation system design air flow rates for the waste storage tanks currently being designed by project W-236A, the Multi-Function Waste Tank Facility (MWTF). The Title 1 design primary tank heat removal system consists of two systems: a primary tank vapor space ventilation system; and an annulus ventilation system. At the conclusion of Title 1 design, air flow rates for the primary and annulus ventilation systems were 960 scfm and 4,400 scfm, respectively, per tank. These design flow rates were capable of removing 1,250,000 Btu/hr from each tank. However, recently completed and ongoing studies have resulted in a design change to reduce the extreme case heat load to 700,000 Btu/hr. This revision of the extreme case heat load, coupled with results of scale model evaporative testing performed by WHC Thermal Hydraulics, allow for a reduction of the design air flow rates for both primary and annulus ventilation systems. Based on the preceding discussion, ICF Kaiser Hanford Co. concludes that the design should incorporate the following design air flow rates: Primary ventilation system--500 scfm maximum and Annulus ventilation system--1,100 scfm maximum. In addition, the minimum air flow rates in the primary and annulus ventilation systems will be investigated during Title 2 design. The results of the Title 2 investigation will determine the range of available temperature control using variable air flows to both ventilation systems.

  2. Effects of saline-water flow rate and air speed on leakage current in RTV coatings

    SciTech Connect

    Kim, S.H.; Hackam, R.

    1995-10-01

    Room temperature vulcanizing (RTV) silicone rubber is increasingly being used to coat porcelain and glass insulators in order to improve their electrical performance in the presence of pollution and moisture. A study of the dependence of leakage current, pulse current count and total charge flowing across the surface of RTV on the flow rate of the saline water and on the compressed air pressure used to create the salt-fog is reported. The fog was directed at the insulating rods either from one or two sides. The RTV was fabricated from polydimethylsiloxane polymer, a filler of alumina trihydrate (ATH), a polymerization catalyst and fumed silica reinforcer, all dispersed in 1,1,1-trichloroethane solvent. The saline water flow rate was varied in the range 0.4 to 2.0 l/min. The compressed air pressure at the input of the fog nozzles was varied from 0.20 to 0.63 MPa. The air speed at the surface of the insulating rods was found to depend linearly on the air pressure measured at the inlet to the nozzles and varied in the range 3 to 14 km/hr. The leakage current increased with increasing flow rate and increasing air speed. This is attributed to the increased loss of hydrophobicity with a larger quantity of saline fog and a larger impact velocities of fog droplets interacting with the surface of the RTV coating.

  3. A Subgrid Model for Predicting Air Entrainment Rates in Bubbly Flows

    NASA Astrophysics Data System (ADS)

    Ma, Jingsen; Oberai, Assad A.; Drew, Donald E.; Lahey, Richard T., Jr.; Moraga, Francisco J.

    2008-11-01

    In this talk we present a fairly simple subgrid air entrainment model that accurately predicts the rate of air entrainment, which is critical in simulating multiphase (air/water) flows. The derivation of this model begins by assuming that a thin sheet of air is carried into the water by the inertia of the liquid at the free surface. A momentum balance on the entrained gas layer results in an expression for the entrained volumetric gas flow rate, in terms of the local liquid velocity, gas viscosity etc., which are readily available from a multiphase RANS-type simulation. This model has been validated against extensive experimental data on both plunging jets and hydraulic jumps over a wide range of liquid velocities. It was implemented in a two-fluid computational fluid dynamics code (CFDShipM) to be used to predict the void fraction distribution underneath a plunging liquid jet at different depths and jet velocities. The results were found to match the experimental observations very well. The application of this model to more challenging problems, including hydraulic jumps and full-scale ship simulations, is currently underway.

  4. Effects of Temperature, Humidity and Air Flow on Fungal Growth Rate on Loaded Ventilation Filters.

    PubMed

    Tang, W; Kuehn, T H; Simcik, Matt F

    2015-01-01

    This study compares the fungal growth ratio on loaded ventilation filters under various temperature, relative humidity (RH), and air flow conditions in a controlled laboratory setting. A new full-size commercial building ventilation filter was loaded with malt extract nutrients and conidia of Cladosporium sphaerospermum in an ASHRAE Standard 52.2 filter test facility. Small sections cut from this filter were incubated under the following conditions: constant room temperature and a high RH of 97%; sinusoidal temperature (with an amplitude of 10°C, an average of 23°C, and a period of 24 hr) and a mean RH of 97%; room temperature and step changes between 97% and 75% RH, 97% and 43% RH, and 97% and 11% RH every 12 hr. The biomass on the filter sections was measured using both an elution-culture method and by ergosterol assay immediately after loading and every 2 days up to 10 days after loading. Fungal growth was detected earlier using ergosterol content than with the elution-culture method. A student's t-test indicated that Cladosporium sphaerospermum grew better at the constant room temperature condition than at the sinusoidal temperature condition. By part-time exposure to dry environments, the fungal growth was reduced (75% and 43% RH) or even inhibited (11% RH). Additional loaded filters were installed in the wind tunnel at room temperature and an RH greater than 95% under one of two air flow test conditions: continuous air flow or air flow only 9 hr/day with a flow rate of 0.7 m(3)/s (filter media velocity 0.15 m/s). Swab tests and a tease mount method were used to detect fungal growth on the filters at day 0, 5, and 10. Fungal growth was detected for both test conditions, which indicates that when temperature and relative humidity are optimum, controlling the air flow alone cannot prevent fungal growth. In real applications where nutrients are less sufficient than in this laboratory study, fungal growth rate may be reduced under the same operating conditions

  5. Biofiltration of air contaminated by styrene: Effect of nitrogen supply, gas flow rate, and inlet concentration

    SciTech Connect

    Jorio, H.; Bibeau, L.; Heitz, M.

    2000-05-01

    The biofiltration process is a promising technology for the treatment of dilute styrene emissions in air. The efficiency of this process is however strongly dependent upon various operational parameters such as the filter bed characteristics, nutrient supplies, input contaminant concentrations, and gas flow rates. The biofiltration of air containing styrene vapors was therefore investigated, employing a novel biomass filter material, in two identical but separate laboratory scale biofiltration units (units 1 and 2), both biofilters being initially inoculated with a microbial consortium. Each biofilter was irrigated with a nutrient solution supplying nitrogen in one of two forms; i.e., mainly as ammonia for unit 1 and exclusively as nitrate for unit 2. The experimental results have revealed that greater styrene elimination rates are achieved in the biofilter supplied with ammonia as the major nitrogen source in comparison to the lesser elimination performance obtained with the nitrate provided biofilter. However, in achieving the high styrene removal rates in the ammonia supplied biofilter, the excess of biomass accumulates on the filtering pellets and causes progressive clogging of the filter media. Furthermore, the effectiveness of nitrate supply as the sole nitrogen nutrient form, on reducing or controlling the biomass accumulation in the filter media in comparison to ammonia, could not be satisfactorily demonstrated because the two biofilters operated with very different styrene elimination capacities. The monitoring of the carbon dioxide concentration profile through both biofilters revealed that the ratio of carbon dioxide produced to the styrene removed was approximately 3/1, which confirms the complete biodegradation of removed styrene, given that some of the organic carbon consumed is also used for the microbial growth. The effects of the most important design parameters, namely styrene input concentrations and gas flow rates, were investigated for each

  6. An experimental investigation on the effects of surface gravity waves on the water evaporation rate in different air flow regimes

    NASA Astrophysics Data System (ADS)

    Jodat, Amin; Moghiman, Mohammad; Shirkhani, Golshad

    2013-12-01

    Estimating rate of evaporation from undisturbed water surfaces to moving and quiet air has been the topic a vast number of research activities. The obvious presence of various shapes of gravity waves on the water body surfaces was the motivation of this experimental investigation. In this investigation experimental measurements have been done to quantify evaporation rate from wavy water surfaces in free, mixed and forced convection regimes. The effects of a wide range of surface gravity waves from low steepness, round shaped crest with slow celerity, to steep and very slight spilling crest waves, on the water evaporation rate have been investigated. A wide range of was achieved by applying different air flow velocities on a large heated wave flume equipped with a wind tunnel. Results reveal that wave motion on the water surface increase the rate of evaporation for all air flow regimes. For free convection, due to the effect of wave motion for pumping rotational airflows at the wave troughs and the dominant effect of natural convection for the air flow advection, the maximum evaporation increment percentage from wavy water surface is about 70 %. For mixed and forced convection, water evaporation rate increment is more sensitive to the air flow velocity for the appearance of very slight spilling on the steep wave crests and the leeward air flow structures.

  7. Effects of oblique air flow on burning rates of square ethanol pool fires.

    PubMed

    Tao, Changfa; He, Yaping; Li, Yuan; Wang, Xishi

    2013-09-15

    The effects of downward airflow on the burning rate and/or burning intensity of square alcohol pool fires for different airflow speeds and directions have been studied experimentally in an inclined wind tunnel. An interesting flame-wrapping phenomenon, caused by impingement of air flow, was observed. The mass burning intensity was found to increase with the airflow speed and the impinging angle. The fuel pan rim temperatures were also measured to study the effect of wind direction and speed on heat transfer from the flame to the fuel source. A model based on heat transfer analysis was developed to correlate the burning intensity with the pan rim characteristic temperature. A good correlation was established between the model results and the experimental results. PMID:23811377

  8. The influence of surface sorption and air flow rate on phthalate emissions from vinyl flooring: Measurement and modeling

    NASA Astrophysics Data System (ADS)

    Liang, Yirui; Xu, Ying

    2015-02-01

    This study investigated the influences of surface sorption and air flow rate on the emission of phthalates from building materials. Controlled tests were conducted in specially designed stainless steel and wood chambers, and the steady-state concentration in the stainless steel chamber was about 2-3 times higher than that in the wood chamber for di(2-ethylhexyl) phthalate (DEHP) and diisononyl phthalate (DINP). The emission rate of phthalates increased in the wood chamber due to the diffusion mass flow through the chamber wall (i.e., surface absorption). The adsorption isotherm of phthalates on the stainless steel surface and the absorption parameters (i.e., diffusion and partition coefficients) of phthalates on the wood surface were determined experimentally, and the values were comparable to those in the literature. The equilibration time scale for phthalates absorbed to the sink reservoir in actual indoor environments was estimated and can be substantial (approximately 80 years), indicating that surface absorption may continuously drive phthalates from their indoor sources to various sinks and thus significantly increase the emission rate of phthalates. The gas-phase concentration of DEHP was measured in two stainless steel chambers operated at flow rates of 300 mL/min and 3000 mL/min, respectively, which were both adjusted to 1000 mL/min after steady state was reached. The gas-phase concentration of DEHP in the chamber was very sensitive to the chamber air flow rate, and higher air flow rates resulted in lower concentration levels. However, the increased emission rate compensated for the dilution in the gas phase and made the DEHP concentration not drop substantially with an increase in the air flow rate. Independently measured or calculated parameters were used to validate a semi-volatile organic compounds (SVOCs) emission model that included absorptive surfaces and for a range of air flow rates, with excellent agreement between the model predictions and the

  9. Theoretical study of the effect of liquid desiccant mass flow rate on the performance of a cross flow parallel-plate liquid desiccant-air dehumidifier

    NASA Astrophysics Data System (ADS)

    Mohammad, Abdulrahman Th.; Mat, Sohif Bin; Sulaiman, M. Y.; Sopian, K.; Al-abidi, Abduljalil A.

    2013-11-01

    A computer simulation using MATLAB is investigated to predict the distribution of air stream parameters (humidity ratio and temperature) as well as desiccant parameters (temperature and concentration) inside the parallel plate absorber. The present absorber consists of fourteen parallel plates with a surface area per unit volume ratio of 80 m2/m3. Calcium chloride as a liquid desiccant flows through the top of the plates to the bottom while the air flows through the gap between the plates making it a cross flow configuration. The model results show the effect of desiccant mass flow rate on the performance of the dehumidifier (moisture removal and dehumidifier effectiveness). Performance comparisons between present cross-flow dehumidifier and another experimental cross-flow dehumidifier in the literature are carried out. The simulation is expected to help in optimizing of a cross flow dehumidifier.

  10. Distribution and variability of the 24-h average air exchange rates and interzonal flow rates in 26 Japanese residences in 5 seasons

    NASA Astrophysics Data System (ADS)

    Shinohara, Naohide; Kataoka, Toshiyuki; Takamine, Koichi; Gamo, Masashi

    2011-07-01

    In this study, to evaluate the distribution of air exchange rates in Japan, daily, seasonal, and inter-residence variabilities were determined as well as the air exchange rate itself. In addition, airflows among multiple zones were also evaluated. For this purpose, the 24 h average air exchange rates and interzonal air flow rates were measured using a passive perfluorocarbon tracer (PFT) method with three kinds of tracer gases for 1 week in three rooms of 26 Japanese residences over five seasons: summer and autumn of 2005, and winter, spring, and summer of 2006. During these seasons, the weekly average air exchange rates were found to be 1.6 ± 1.7, 0.58 ± 0.94, 0.61 ± 0.93, 1.2 ± 2.5, and 1.7 ± 1.8 h -1, respectively. Two-way repeated measure analysis of variance (ANOVA) revealed that the air exchange rates differed significantly with respect to the seasons, residences, and interaction of seasons and residences ( p < 0.01). In addition, the air exchange rates in both summers and spring were statistically higher than those in autumn and winter (Sheffe test, p < 0.01). According to the ANOVA, the percentage contribution of inter-residence variability, seasonal variability, interaction of seasonal and inter-residence variabilities, and daily variability to the total variability of the 24 h average air exchange rates in the present survey was 51%, 44%, 3.7%, and 1.0%, respectively.

  11. Air Change Rates and Interzonal Flows in Residences, and the Need for Multi-Zone Models for Exposure and Health Analysis

    EPA Science Inventory

    Air change rates (ACRs) and interzonal flows are key determinants of indoor air quality (IAQ) and building energy use. This paper characterizes ACRs and interzonal flows in 126 houses, and evaluates effects of these parameters on IAQ. ACRs measured using weeklong tracer measureme...

  12. Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower

    PubMed Central

    2012-01-01

    The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p < 0.001) from 76.8 ± 1.8% to 85.7 ± 1.2%. Analysis of covariance method followed by Tukey post-hoc test of 92 tests did not show a significant change in removal efficiency between liquid flow rates of 1.5, 2.5 and 3.5 L/min (p = 0.811). On the other hand, with fixed pressure loss across the tower, by increasing the liquid/gas (L/G) mass ratio, the average removal efficiency decreased significantly (p = 0.001) from 89.9% at L/G of <2 to 83.1% at L/G of 2–3 and further to 80.2% at L/G of >3, respectively. L/G of 2–3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream. PMID:23369487

  13. Model-based flow rate control for an orfice-type low-volume air sampler

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The standard method of measuring air suspended particulate matter concentration per volume of air consists of continuously drawing a defined volume of air across a filter over an extended period of time, then measuring the mass of the filtered particles and dividing it by the total volume sampled ov...

  14. Influence of specimen size, tray inclination and air flow rate on the emission of gases from biomass combustion

    NASA Astrophysics Data System (ADS)

    Amorim, E. B.; Carvalho, J. A.; Soares Neto, T. G.; Anselmo, E.; Saito, V. O.; Dias, F. F.; Santos, J. C.

    2013-08-01

    Experiments of biomass combustion were performed to determine whether specimen size, tray inclination, or combustion air flow rate was the factor that most affects the emission of carbon dioxide, carbon monoxide, and methane. The chosen biomass was Eucalyptus citriodora, a very abundant species in Brazil, utilized in many industrial applications, including combustion for energy generation. Analyses by gas chromatograph and specific online instruments were used to determine the concentrations of the main emitted gases, and the following figures were found for the emission factors: 1400 ± 101 g kg-1 of CO2, 50 ± 13 g kg-1 of CO, and 3.2 ± 0.5 g kg-1 of CH4, which agree with values published in the literature for biomass from the Amazon rainforest. Statistical analysis of the experiments determined that specimen size most significantly affected the emission of gases, especially CO2 and CO.

  15. Influence of air flow rate on emission of DEHP from vinyl flooring in the emission cell FLEC: Measurements and CFD simulation

    NASA Astrophysics Data System (ADS)

    Clausen, Per Axel; Liu, Zhe; Xu, Ying; Kofoed-Sørensen, Vivi; Little, John C.

    2010-07-01

    The emission of di-(2-ethylhexyl)phthalate (DEHP) from one type of vinyl flooring with ˜15% (w/w) DEHP as plasticizer was measured at 22 °C in five FLECs + one blank FLEC (Field and Laboratory Emission Cell). Initially, the flow through all FLECs was 450 ml min -1. After 689 days the flows were changed to 1000 ml min -1, 1600 ml min -1, 2300 ml min -1, and 3000 ml min -1, respectively, in four FLECs, and kept at 450 ml min -1 in one FLEC. Air samples were collected from the effluent air at regular intervals. After 1190 days the experiments were terminated and the interior surfaces of all six FLECs were rinsed with methanol to estimate the internal surface concentrations of DEHP. The DEHP air concentration and specific emission rate (SER) at steady state was estimated for the five different flow rates. The steady-state concentrations decreased slightly with increasing air flow with only the two highest flow rates resulting in significantly lower concentrations. In contrast, the SERs increased significantly. Despite large variation, the internal surface concentrations appeared to decrease slightly with increasing FLEC flow. Computational fluid dynamic (CFD) simulations suggest that the interior gas and surface concentrations were roughly uniform for the low flow case (450 ml min -1), under which, the partitioning between the FLEC internal surface and chamber air was examined. Although paired t-tests showed no difference between CFD and experimental results for DEHP air concentrations and SERs at steady-state conditions, CFD indicated that the experimental DEHP surface concentrations in the FLECs were underestimated. In conclusion, the experiments showed that the emission of DEHP from vinyl flooring is subject to "external" control and that the SER is strongly and positively dependent on the air exchange rate. However, the increased SER almost compensates for the decrease in gas-phase concentration caused by the increased air exchange.

  16. Characteristic of flotation deinking using bio and synthetic surfactant at different air flow rate

    NASA Astrophysics Data System (ADS)

    Trismawati, Wardana, I. N. G.; Hamidi, Nurkholis; Sasongko, Mega Nur

    2016-03-01

    Flotation deinking has industrially applied but several problems keep unsolved because limitations have to compete with several variables present. Flotation deinking is multi variables process, so studying flotation deinking is still interesting. In this research, the amount of variables was reduced and focused to the performance comparison between flotation deinking of old newspaper (ONP) using biodegradable fatty acid of morinda citrifolia as the raw bio surfactant (RBS) and biodegradable fatty acid of palm oil that had been converted to be commercial surfactant (CS). The flotation was done at laboratory flotation cell equipped with orifice at different diameter (orifice number 20, 40 and 60) with adjustable airflow rate. Brightness and Effective Residual Ink Concentration (ERIC) of the deinked pulp were measured. The best results were achieved on orifice number 40 with the highest brightness of 41.96 °ISO and 40.96 °ISO when using CS and RBS respectively, and lowest ERIC of 896.82 ppm and 1001.72 ppm when using CS and RBS respectively. The percentage delta of deinking power characteristic between CS and RBS was 2.36% and 11.70% for brightness and ERIC, respectively.

  17. Terminal Air Flow Planning

    NASA Technical Reports Server (NTRS)

    Denery, Dallas G.; Erzberger, Heinz; Edwards, Thomas A. (Technical Monitor)

    1998-01-01

    The Center TRACON Automation System (CTAS) will be the basis for air traffic planning and control in the terminal area. The system accepts arriving traffic within an extended terminal area and optimizes the flow based on current traffic and airport conditions. The operational use of CTAS will be presented together with results from current operations.

  18. Effect of air flow rate on the polyphenols content and antioxidant capacity of convective dried cactus pear cladodes (Opuntia ficus indica).

    PubMed

    Gallegos-Infante, José-Alberto; Rocha-Guzman, Nuria-Elizabeth; González-Laredo, Ruben-Francisco; Reynoso-Camacho, Rosalia; Medina-Torres, Luis; Cervantes-Cardozo, Veronica

    2009-01-01

    The interest in nopal has encouraged the use of dehydration; there are few studies about the effect of process parameters on the nopal polyphenol content and antioxidant activity. The objective of the present work was to evaluate the effect of air-drying flow rates on the amount and antioxidant capacity of extracts of Opuntia ficus indica cladodes. Nopal was dried at 45 degrees C and air flow rates of 3 and 5 m/sec. Samples were analyzed for moisture, total polyphenol, flavonoid, and flavonol contents, chain-breaking activity, inhibition of low-density lipoprotein and deoxyribose oxidation. Nopal drying at an air flow rate of 3 m/sec showed higher values of phenols, flavonoids and flavonols. The best value of low-density lipoprotein inhibition and deoxyribose was found at 1,000 microg/ml. The air flow rate affected the amount of polyphenols and the OH( . ) radical scavenging, but did not modify the chain-breaking activity and the low-density lipoprotein inhibition activity. PMID:19468951

  19. Air Change Rates and Interzonal Flows in Residences, and the Need for Multi-Zone Models for Exposure and Health Analyses

    PubMed Central

    Du, Liuliu; Batterman, Stuart; Godwin, Christopher; Chin, Jo-Yu; Parker, Edith; Breen, Michael; Brakefield, Wilma; Robins, Thomas; Lewis, Toby

    2012-01-01

    Air change rates (ACRs) and interzonal flows are key determinants of indoor air quality (IAQ) and building energy use. This paper characterizes ACRs and interzonal flows in 126 houses, and evaluates effects of these parameters on IAQ. ACRs measured using weeklong tracer measurements in several seasons averaged 0.73 ± 0.76 h−1 (median = 0.57 h−1, n = 263) in the general living area, and much higher, 1.66 ± 1.50 h−1 (median = 1.23 h−1, n = 253) in bedrooms. Living area ACRs were highest in winter and lowest in spring; bedroom ACRs were highest in summer and lowest in spring. Bedrooms received an average of 55 ± 18% of air from elsewhere in the house; the living area received only 26 ± 20% from the bedroom. Interzonal flows did not depend on season, indoor smoking or the presence of air conditioners. A two-zone IAQ model calibrated for the field study showed large differences in pollutant levels between the living area and bedroom, and the key parameters affecting IAQ were emission rates, emission source locations, air filter use, ACRs, interzonal flows, outdoor concentrations, and PM penetration factors. The single-zone models that are commonly used for residences have substantial limitations and may inadequately represent pollutant concentrations and exposures in bedrooms and potentially other environments other where people spend a substantial fraction of time. PMID:23235286

  20. Improvement of oxygen transfer coefficient during Penicillium canescens culture. Influence of turbine design, agitation speed, and air flow rate on xylanase production.

    PubMed

    Gaspar, A; Strodiot, L; Thonart, P

    1998-01-01

    To improve xylanase productivity from Penicillium canescens 10-10c culture, an optimization of oxygen supply is required. Because the strain is sensitive to shear forces, leading to lower xylanase productivity as to morphological alteration, vigorous mixing is not desired. The influence of turbine design, agitation speed, and air flow rate on K1a (global mass transfer coefficient, h(-1)) and enzyme production is discussed. K1a values increased with agitation speed and air flow rate, whatever the impeller, in our assay conditions. Agitation had more influence on K1a values than air flow, when a disk-mounted blade's impeller (DT) is used; an opposite result was obtained with a hub-mounted pitched blade's impeller (PBT). Xylanase production appeared as a function of specific power (W/m3), and an optimum was found in 20 and 100 L STRs fitted with DT impellers. On the other hand, the use of a hub-mounted pitched blade impeller (PBT8), instead of a disk-mounted blade impeller (DT4), reduced the lag time of hemicellulase production and increased xylanase productivity 1.3-fold. PMID:18576019

  1. EFFECTS OF COVAPORS ON ADSORPTION RATE COEFFICIENTS OF ORGANIC VAPORS ADSORBED ONTO ACTIVATED CARBON FROM FLOWING AIR

    SciTech Connect

    G. WOOD

    2000-12-01

    Published breakthrough time, adsorption rate, and capacity data for components of organic vapor mixtures adsorbed from flows through fixed activated carbon beds have been analyzed. Capacities (as stoichiometric centers of constant pattern breakthrough curves) yielded stoichiometric times {tau}, which are useful for determining elution orders of mixture components. We also calculated adsorption rate coefficients k{sub v} of the Wheeler (or, more general Reaction Kinetic) breakthrough curve equation, when not reported, from breakthrough times and {tau}. Ninety-five k{sub v} (in mixture)/ k{sub v} (single vapor) ratios at similar vapor concentrations were calculated and averaged for elution order categories. For 43 first-eluting vapors the average ratio (1.07) was statistically no different (0.21 standard deviation) than unity, so that we recommend using the single-vapor k{sub v} for such. Forty-seven second-eluting vapor ratios averaged 0.85 (0.24 standard deviation), also not significantly different from unity; however, other evidence and considerations lead us recommend using k{sub v} (in mixture) = 0.85 k{sub v} (single vapor). Five third- and fourth-eluting vapors gave an average of 0.56 (0.16 standard deviation) for a recommended k{sub v} (in mixture) = 0.56 k{sub v} (single vapor) for such.

  2. Natural Flow Air Cooled Photovoltaics

    NASA Astrophysics Data System (ADS)

    Tanagnostopoulos, Y.; Themelis, P.

    2010-01-01

    Our experimental study aims to investigate the improvement in the electrical performance of a photovoltaic installation on buildings through cooling of the photovoltaic panels with natural air flow. Our experimental study aims to investigate the improvement in the electrical performance of a photovoltaic installation on buildings through cooling of the photovoltaic panels with natural air flow. We performed experiments using a prototype based on three silicon photovoltaic modules placed in series to simulate a typical sloping building roof with photovoltaic installation. In this system the air flows through a channel on the rear side of PV panels. The potential for increasing the heat exchange from the photovoltaic panel to the circulating air by the addition of a thin metal sheet (TMS) in the middle of air channel or metal fins (FIN) along the air duct was examined. The operation of the device was studied with the air duct closed tightly to avoid air circulation (CLOSED) and the air duct open (REF), with the thin metal sheet (TMS) and with metal fins (FIN). In each case the experiments were performed under sunlight and the operating parameters of the experimental device determining the electrical and thermal performance of the system were observed and recorded during a whole day and for several days. We collected the data and form PV panels from the comparative diagrams of the experimental results regarding the temperature of solar cells, the electrical efficiency of the installation, the temperature of the back wall of the air duct and the temperature difference in the entrance and exit of the air duct. The comparative results from the measurements determine the improvement in electrical performance of the photovoltaic cells because of the reduction of their temperature, which is achieved by the naturally circulating air.

  3. Dual-Flow-Rate Valve

    NASA Technical Reports Server (NTRS)

    Allbritain, R. H.

    1986-01-01

    Flow-control device precisely adjusted for two rates. Heart of twoposition valve is sliding poppet. At far-right position, poppet allows low flow. At far-left position, allows high flow. Valve supplies high-pressure gas at either of two preselected flow rates. Valve adjustable between 0.12 and 1.2 lb/s (0.054 and 0.54 kg/s) of hydrogen at 3,300 lb/in.2 (23 MN/m2) and 80 degrees F (27 degrees C). Two flow rates preadjusted between these limits in increments of 0.01 lb/s (0.0045 kg/s).

  4. Air velocity distributions from a variable-rate air-assisted sprayer for tree applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A capability that implements tree structure to control liquid and air flow rates is the preferential design in the development of variable-rate orchard and nursery sprayers. Air jet velocity distributions from an air assisted, five-port sprayer which was under the development to achieve variable-rat...

  5. Measuring Your Peak Flow Rate

    MedlinePlus

    ... meter. Proper cleaning with mild detergent in hot water will keep your peak flow meter working accurately and may keep you healthier. Related Content News: American Lung Association Applauds EPA’s Update to Cross-State Air Pollution Rule News: American Lung Association Invests More Than $ ...

  6. Columbus Payloads Flow Rate Anomalies

    NASA Technical Reports Server (NTRS)

    Quaranta, Albino; Bufano, Gaetana; DePalo, Savino; Holt, James M.; Szigetvari, Zoltan; Palumberi, Sergio; Hinderer, S.

    2011-01-01

    The Columbus Active Thermal Control System (ATCS) is the main thermal bus for the pressurized racks working inside the European laboratory. One of the ATCS goals is to provide proper water flow rate to each payload (P/L) by controlling actively the pressure drop across the common plenum distribution piping. Overall flow measurement performed by the Water Pump Assembly (WPA) is the only flow rate monitor available at system level and is not part of the feedback control system. At rack activation the flow rate provided by the system is derived on ground by computing the WPA flow increase. With this approach, several anomalies were raised during these 3 years on-orbit, with the indication of low flow rate conditions on the European racks FSL, BioLab, EDR and EPM. This paper reviews the system and P/Ls calibration approach, the anomalies occurred, the engineering evaluation on the measurement approach and the accuracy improvements proposed, the on-orbit test under evaluation with NASA and finally discusses possible short and long term solutions in case of anomaly confirmation.

  7. Evaporation of stationary alcohol layer in minichannel under air flow

    NASA Astrophysics Data System (ADS)

    Afanasyev, Ilya; Orlova, Evgenija; Feoktistov, Dmitriy

    2015-01-01

    This paper presents experimental investigation of effect of the gas flow rate moving parallel to the stationary liquid layer on the evaporation rate under the conditions of formation of a stable plane "liquid-gas" interface. The average evaporation flow rate of liquid layer (ethanol) by the gas flow (air) has been calculated using two independent methods. Obtained results have been compared with previously published data.

  8. Air-flow regulation system for a coal gasifier

    DOEpatents

    Fasching, George E.

    1984-01-01

    An improved air-flow regulator for a fixed-bed coal gasifier is provided which allows close air-flow regulation from a compressor source even though the pressure variations are too rapid for a single primary control loop to respond. The improved system includes a primary controller to control a valve in the main (large) air supply line to regulate large slow changes in flow. A secondary controller is used to control a smaller, faster acting valve in a secondary (small) air supply line parallel to the main line valve to regulate rapid cyclic deviations in air flow. A low-pass filter with a time constant of from 20 to 50 seconds couples the output of the secondary controller to the input of the primary controller so that the primary controller only responds to slow changes in the air-flow rate, the faster, cyclic deviations in flow rate sensed and corrected by the secondary controller loop do not reach the primary controller due to the high frequency rejection provided by the filter. This control arrangement provides at least a factor of 5 improvement in air-flow regulation for a coal gasifier in which air is supplied by a reciprocating compressor through a surge tank.

  9. Air kerma rate constants for radionuclides.

    PubMed

    Wasserman, H; Groenewald, W

    1988-01-01

    Conversion to SI units requires that the exposure rate constant which was usually quoted in R.h-1.mCi-1.cm2 be replaced by the air kerma rate constant with units m2.Gy.Bq-1.s-1. The conversion factor is derived and air kerma rate constants for 30 radionuclides used in nuclear medicine and brachytherapy are listed. A table for calculation of air kerma rates for other radionuclides is also given. To calculate absorbed dose to tissue, the air kerma rate has to be multiplied by approximately 1.1. A dose equivalent rate constant is thus listed which allows direct calculation of dose equivalent rate to soft tissue without resorting to exposure rate constants tabulated in the special units R.m2.mCi-1.h-1 which should no longer be used. PMID:3208786

  10. Air Controlman 1 & C: Rate Training Manual.

    ERIC Educational Resources Information Center

    Naval Training Command, Pensacola, FL.

    The manual is designed for use in preparing for advancement within the Navy Air Controlman rating, which designates a professional air traffic controller, unlike the more specialized center or tower controllers. However, minimum qualifications for the rating include completion of the Federal Aviation Administration (FAA) written examination for…

  11. Development of a flow rate monitoring method for the wearable ventricular assist device driver.

    PubMed

    Ohnuma, Kentaro; Homma, Akihiko; Sumikura, Hirohito; Tsukiya, Tomonori; Takewa, Yoshiaki; Mizuno, Toshihide; Mukaibayashi, Hiroshi; Kojima, Koichi; Katano, Kazuo; Taenaka, Yoshiyuki; Tatsumi, Eisuke

    2015-06-01

    Our research institute has been working on the development of a compact wearable drive unit for an extracorporeal ventricular assist device (VAD) with a pneumatically driven pump. A method for checking the pump blood flow on the side of the drive unit without modifying the existing blood pump and impairing the portability of it will be useful. In this study, to calculate the pump flow rate indirectly from measuring the flow rate of the driving air of the VAD air chamber, we conducted experiments using a mock circuit to investigate the correlation between the air flow rate and the pump flow rate as well as its accuracy and error factors. The pump flow rate was measured using an ultrasonic flow meter at the inflow and outflow tube, and the air flow was measured using a thermal mass flow meter at the driveline. Similarity in the instantaneous waveform was confirmed between the air flow rate in the driveline and the pump flow rate. Some limitations of this technique were indicated by consideration of the error factors. A significant correlation was found between the average pump flow rate in the ejecting direction and the average air flow rate in the ejecting direction (R2 = 0.704-0.856), and the air flow rate in the filling direction (R2 = 0.947-0.971). It was demonstrated that the average pump flow rate was estimated exactly in a wide range of drive conditions using the air flow of the filling phase. PMID:25500948

  12. Effect of air flow on tubular solar still efficiency

    PubMed Central

    2013-01-01

    Background An experimental work was reported to estimate the increase in distillate yield for a compound parabolic concentrator-concentric tubular solar still (CPC-CTSS). The CPC dramatically increases the heating of the saline water. A novel idea was proposed to study the characteristic features of CPC for desalination to produce a large quantity of distillate yield. A rectangular basin of dimension 2 m × 0.025 m × 0.02 m was fabricated of copper and was placed at the focus of the CPC. This basin is covered by two cylindrical glass tubes of length 2 m with two different diameters of 0.02 m and 0.03 m. The experimental study was operated with two modes: without and with air flow between inner and outer tubes. The rate of air flow was fixed throughout the experiment at 4.5 m/s. On the basis of performance results, the water collection rate was 1445 ml/day without air flow and 2020 ml/day with air flow and the efficiencies were 16.2% and 18.9%, respectively. Findings The experimental study was operated with two modes: without and with air flow between inner and outer tubes. The rate of air flow was fixed throughout the experiment at 4.5 m/s. Conclusions On the basis of performance results, the water collection rate was 1445 ml/day without air flow and 2020 ml/day with air flow and the efficiencies were 16.2% and 18.9%, respectively. PMID:23587020

  13. Measuring Outdoor Air Intake Rates into Existing Building

    SciTech Connect

    Fisk, William; Sullivan, Douglas; Cohen, Sebastian; Han, Hwataik

    2009-04-16

    Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two new measurement approaches. Laboratory experiments determined that OA flow rates were measurable with errors generally less than 10 percent using electronic air velocity probes installed between OA intake louver blades or at the outlet face of louvers. High accuracy was maintained with OA flow rates as low as 15 percent of the maximum for the louvers. Thus, with this measurement approach HVAC systems do not need separate OA intakes for minimum OA supply. System calibration parameters are required for each unique combination of louver type and velocity sensor location but calibrations are not necessary for each system installation. The research also determined that the accuracy of measuring OA flow rates with velocity probes located in the duct downstream of the intake louver was not improved by installing honeycomb airflow straighteners upstream of the probes. Errors varied with type of upstream louver, were as high as 100 percent, and were often greater than 25 percent. In conclusion, use of electronic air velocity probes between the blades of OA intake louvers or at the outlet face of louvers is a highly promising means of accurately measuring rates of OA flow into HVAC systems. The use of electronic velocity probes downstream of airflow straighteners is less promising, at least with the relatively small OA HVAC inlet systems employed in this research.

  14. Computation of flow and heat transfer in rotating cavities with peripheral flow of cooling air.

    PubMed

    Kiliç, M

    2001-05-01

    Numerical solutions of the Navier-Stokes equations have been used to model the flow and the heat transfer that occurs in the internal cooling-air systems of gas turbines. Computations are performed to study the effect of gap ratio, Reynolds number and the mass flow rate on the flow and the heat transfer structure inside isothermal and heated rotating cavities with peripheral flow of cooling air. Computations are compared with some of the recent experimental work on flow and heat transfer in rotating-cavities. The agreement between the computed and the available experimental data is reasonably good. PMID:11460668

  15. Simulator Of Rain In Flowing Air

    NASA Technical Reports Server (NTRS)

    Clayton, Richard M.; Cho, Young I.; Shakkottai, Parthasarathy; Back, Lloyd H.

    1989-01-01

    Report describes relatively inexpensive apparatus that creates simulated precipitation from drizzle to heavy rain in flowing air. Small, positive-displacement pump and water-injecting device positioned at low-airspeed end of converging section of wind tunnel 10 in. in diameter. Drops injected by array entrained in flow of air as it accelerates toward narrower outlet, 15 in. downstream. Outlet 5 in. in diameter.

  16. Numerical simulation of air flow in a model of lungs with mouth cavity

    NASA Astrophysics Data System (ADS)

    Elcner, Jakub; Lizal, Frantisek; Jedelsky, Jan; Jicha, Miroslav

    2012-04-01

    The air flow in a realistic geometry of human lung is simulated with computational flow dynamics approach as stationary inspiration. Geometry used for the simulation includes oral cavity, larynx, trachea and bronchial tree up to the seventh generation of branching. Unsteady RANS approach was used for the air flow simulation. Velocities corresponding to 15, 30 and 60 litres/min of flow rate were set as boundary conditions at the inlet to the model. These flow rates are frequently used as a representation of typical human activities. Character of air flow in the model for these different flow rates is discussed with respect to future investigation of particle deposition.

  17. Air flow cued spatial learning in mice.

    PubMed

    Bouchekioua, Youcef; Mimura, Masaru; Watanabe, Shigeru

    2015-01-01

    Spatial learning experiments in rodents typically employ visual cues that are associated with a goal place, even though it is now well established that they have poor visual acuity. We assessed here the possibility of spatial learning in mice based on an air flow cue in a dry version of the Morris water maze task. A miniature fan was placed at each of the four cardinal points of the circular maze, but only one blew air towards the centre of the maze. The three other fans were blowing towards their own box. The mice were able to learn the task only if the spatial relationship between the air flow cue and the position of the goal place was kept constant across trials. A change of this spatial relationship resulted in an increase in the time to find the goal place. We report here the first evidence of spatial learning relying on an air flow cue. PMID:25257773

  18. On the impact of entrapped air in infiltration under ponding conditions. Part a: Preferential air flow path effects on infiltration

    NASA Astrophysics Data System (ADS)

    Mizrahi, Guy; Weisbrod, Noam; Furman, Alex

    2015-04-01

    Entrapped air effects on infiltration under ponding conditions could be important for massive infiltration of managed aquifer recharge (MAR) or soil aquifer treatment (SAT) of treated wastewater. Earlier studies found that under ponding conditions, air is being entrapped and compressed until it reaches a pressure which will enable the air to escape (unstable air flow). They also found that entrapped air could reduce infiltration by 70-90%. Most studies have dealt with entrapped air effects when soil surface topography is flat. The objective of this study is to investigate, under ponding conditions, the effects of: (1) irregular surface topography on preferential air flow path development (stable air flow); (2) preferential air flow path on infiltration; and (3) hydraulic head on infiltration when air is trapped. Column experiments were used to investigate these particular effects. A 140 cm deep and 30 cm wide column packed with silica sand was used under two boundary conditions: in the first, air can only escape vertically upward through the soil surface; in the second, air is free to escape through 20 ports installed along the column perimeter. The surface was flooded with 13 liters of water, with ponding depth decreasing with time. Two soil surface conditions were tested: flat surface and irregular surface (high and low surface zones). Additionally, Helle-show experiments were conducted in order to obtain a visual observation of preferential air flow path development. The measurements were carried out using a tension meter, air pressure transducers, TDR and video cameras. It was found that in irregular surfaces, stable air flow through preferential paths was developed in the high altitude zones. Flat surface topography caused unstable air flow through random paths. Comparison between irregular and flat surface topography showed that the entrapped air pressure was lower and the infiltration rate was about 40% higher in the irregular surface topography than in the

  19. Flow rate measuring devices for gas flows

    NASA Astrophysics Data System (ADS)

    Bonfig, K. W.

    1985-07-01

    Flowrate measuring devices are described: volume meter with fixed or mobile walls; turbine meter; throttling procedure; ultrasonic and Doppler methods; vortex method; rotary flowmeter; and swinging body flow measuring procedure. Flowrate can also be measured from the force exerted on bodies immersed in a fluid or based on thermodynamical principles. The characteristics and operating envelope of each device/method are given.

  20. Air flow through poppet valves

    NASA Technical Reports Server (NTRS)

    Lewis, G W; Nutting, E M

    1920-01-01

    Report discusses the comparative continuous flow characteristics of single and double poppet valves. The experimental data presented affords a direct comparison of valves, single and in pairs of different sizes, tested in a cylinder designed in accordance with current practice in aviation engines.

  1. Flow rate logging seepage meter

    NASA Technical Reports Server (NTRS)

    Reay, William G. (Inventor); Walthall, Harry G. (Inventor)

    1996-01-01

    An apparatus for remotely measuring and logging the flow rate of groundwater seepage into surface water bodies. As groundwater seeps into a cavity created by a bottomless housing, it displaces water through an inlet and into a waterproof sealed upper compartment, at which point, the water is collected by a collection bag, which is contained in a bag chamber. A magnet on the collection bag approaches a proximity switch as the collection bag fills, and eventually enables the proximity switch to activate a control circuit. The control circuit then rotates a three-way valve from the collection path to a discharge path, enables a data logger to record the time, and enables a pump, which discharges the water from the collection bag, through the three-way valve and pump, and into the sea. As the collection bag empties, the magnet leaves the proximity of the proximity switch, and the control circuit turns off the pump, resets the valve to provide a collection path, and restarts the collection cycle.

  2. Single chamber fuel cells: Flow geometry, rate and composition considerations

    SciTech Connect

    Stefan, Ionel C.; Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

    2003-11-17

    Four different single chamber fuel cell designs were compared using propane-air gas mixtures. Gas flow around the electrodes has a significant influence on the open circuit voltage and the power density of the cell. The strong influence of flow geometry is likely due to its effect on gas composition, particularly on the oxygen chemical potential at the two electrodes as a result of gas mixing. The chamber design which exposes the cathode first to the inlet gas was found to yield the best performance at lower flow rates, while the open tube design with the electrodes equally exposed to the inlet gas worked best at higher flow rates.

  3. Cross-flow versus counterflow air-stripping towers

    SciTech Connect

    Little, J.C.; Marinas, B.J.

    1997-07-01

    Mass-transfer and pressure-drop packing performance correlations are used together with tower design equations and detailed cost models to compare the effectiveness of cross-flow and counterflow air stripping towers over a wide range of contaminant volatility. Cross-flow towers are shown to offer a significant economic advantage over counterflow towers when stripping low volatility organic contaminants primarily due to savings in energy costs. These savings increase as contaminant volatility decreases and as water flow rate increases. A further advantage of the cross-flow configuration is that it extends the feasible operating range for air stripping as cross-flow towers can accommodate higher air-to-water flow ratios than conventional counterflow towers. Finally it is shown that the optimized least-cost design for both counterflow and cross-flow towers varies with Henry`s law constant, water flow rate, and percent removal, but that the optimum is virtually insensitive to other cost and operating variables. This greatly simplifies the tower design procedure.

  4. 40 CFR 91.416 - Intake air flow measurement specifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Intake air flow measurement... Procedures § 91.416 Intake air flow measurement specifications. (a) If used, the engine intake air flow measurement method used must have a range large enough to accurately measure the air flow over the...

  5. Performance of High Flow Rate Samplers for Respirable Particle Collection

    PubMed Central

    Lee, Taekhee; Kim, Seung Won; Chisholm, William P.; Slaven, James; Harper, Martin

    2010-01-01

    The American Conference of Governmental Industrial hygienists (ACGIH) lowered the threshold limit value (TLV) for respirable crystalline silica (RCS) exposure from 0.05 to 0.025 mg m−3 in 2006. For a working environment with an airborne dust concentration near this lowered TLV, the sample collected with current standard respirable aerosol samplers might not provide enough RCS for quantitative analysis. Adopting high flow rate sampling devices for respirable dust containing silica may provide a sufficient amount of RCS to be above the limit of quantification even for samples collected for less than full shift. The performances of three high flow rate respirable samplers (CIP10-R, GK2.69, and FSP10) have been evaluated in this study. Eleven different sizes of monodisperse aerosols of ammonium fluorescein were generated with a vibrating orifice aerosol generator in a calm air chamber in order to determine the sampling efficiency of each sampler. Aluminum oxide particles generated by a fluidized bed aerosol generator were used to test (i) the uniformity of a modified calm air chamber, (ii) the effect of loading on the sampling efficiency, and (iii) the performance of dust collection compared to lower flow rate cyclones in common use in the USA (10-mm nylon and Higgins–Dewell cyclones). The coefficient of variation for eight simultaneous samples in the modified calm air chamber ranged from 1.9 to 6.1% for triplicate measures of three different aerosols. The 50% cutoff size (50dae) of the high flow rate samplers operated at the flow rates recommended by manufacturers were determined as 4.7, 4.1, and 4.8 μm for CIP10-R, GK2.69, and FSP10, respectively. The mass concentration ratio of the high flow rate samplers to the low flow rate cyclones decreased with decreasing mass median aerodynamic diameter (MMAD) and high flow rate samplers collected more dust than low flow rate samplers by a range of 2–11 times based on gravimetric analysis. Dust loading inside the high

  6. Performance of high flow rate samplers for respirable particle collection.

    PubMed

    Lee, Taekhee; Kim, Seung Won; Chisholm, William P; Slaven, James; Harper, Martin

    2010-08-01

    The American Conference of Governmental Industrial hygienists (ACGIH) lowered the threshold limit value (TLV) for respirable crystalline silica (RCS) exposure from 0.05 to 0.025 mg m(-3) in 2006. For a working environment with an airborne dust concentration near this lowered TLV, the sample collected with current standard respirable aerosol samplers might not provide enough RCS for quantitative analysis. Adopting high flow rate sampling devices for respirable dust containing silica may provide a sufficient amount of RCS to be above the limit of quantification even for samples collected for less than full shift. The performances of three high flow rate respirable samplers (CIP10-R, GK2.69, and FSP10) have been evaluated in this study. Eleven different sizes of monodisperse aerosols of ammonium fluorescein were generated with a vibrating orifice aerosol generator in a calm air chamber in order to determine the sampling efficiency of each sampler. Aluminum oxide particles generated by a fluidized bed aerosol generator were used to test (i) the uniformity of a modified calm air chamber, (ii) the effect of loading on the sampling efficiency, and (iii) the performance of dust collection compared to lower flow rate cyclones in common use in the USA (10-mm nylon and Higgins-Dewell cyclones). The coefficient of variation for eight simultaneous samples in the modified calm air chamber ranged from 1.9 to 6.1% for triplicate measures of three different aerosols. The 50% cutoff size ((50)d(ae)) of the high flow rate samplers operated at the flow rates recommended by manufacturers were determined as 4.7, 4.1, and 4.8 microm for CIP10-R, GK2.69, and FSP10, respectively. The mass concentration ratio of the high flow rate samplers to the low flow rate cyclones decreased with decreasing mass median aerodynamic diameter (MMAD) and high flow rate samplers collected more dust than low flow rate samplers by a range of 2-11 times based on gravimetric analysis. Dust loading inside the

  7. Gas flow meter and method for measuring gas flow rate

    DOEpatents

    Robertson, Eric P.

    2006-08-01

    A gas flow rate meter includes an upstream line and two chambers having substantially equal, fixed volumes. An adjustable valve may direct the gas flow through the upstream line to either of the two chambers. A pressure monitoring device may be configured to prompt valve adjustments, directing the gas flow to an alternate chamber each time a pre-set pressure in the upstream line is reached. A method of measuring the gas flow rate measures the time required for the pressure in the upstream line to reach the pre-set pressure. The volume of the chamber and upstream line are known and fixed, thus the time required for the increase in pressure may be used to determine the flow rate of the gas. Another method of measuring the gas flow rate uses two pressure measurements of a fixed volume, taken at different times, to determine the flow rate of the gas.

  8. High Lapse Rates in AIRS Retrieved Temperatures in Cold Air Outbreaks

    NASA Technical Reports Server (NTRS)

    Fetzer, Eric J.; Kahn, Brian; Olsen, Edward T.; Fishbein, Evan

    2004-01-01

    The Atmospheric Infrared Sounder (AIRS) experiment, on NASA's Aqua spacecraft, uses a combination of infrared and microwave observations to retrieve cloud and surface properties, plus temperature and water vapor profiles comparable to radiosondes throughout the troposphere, for cloud cover up to 70%. The high spectral resolution of AIRS provides sensitivity to important information about the near-surface atmosphere and underlying surface. A preliminary analysis of AIRS temperature retrievals taken during January 2003 reveals extensive areas of superadiabatic lapse rates in the lowest kilometer of the atmosphere. These areas are found predominantly east of North America over the Gulf Stream, and, off East Asia over the Kuroshio Current. Accompanying the high lapse rates are low air temperatures, large sea-air temperature differences, and low relative humidities. Imagery from a Visible / Near Infrared instrument on the AIRS experiment shows accompanying clouds. These lines of evidence all point to shallow convection in the bottom layer of a cold air mass overlying warm water, with overturning driven by heat flow from ocean to atmosphere. An examination of operational radiosondes at six coastal stations in Japan shows AIRS to be oversensitive to lower tropospheric lapse rates due to systematically warm near-surface air temperatures. The bias in near-surface air temperature is seen to be independent of sea surface temperature, however. AIRS is therefore sensitive to air-sea temperature difference, but with a warm atmospheric bias. A regression fit to radiosondes is used to correct AIRS near-surface retrieved temperatures, and thereby obtain an estimate of the true atmosphere-ocean thermal contrast in five subtropical regions across the north Pacific. Moving eastward, we show a systematic shift in this air-sea temperature differences toward more isothermal conditions. These results, while preliminary, have implications for our understanding of heat flow from ocean to

  9. Theoretical Analysis of Maximum Flow Declination Rate versus Maximum Area Declination Rate in Phonation

    ERIC Educational Resources Information Center

    Titze, Ingo R.

    2006-01-01

    Purpose: Maximum flow declination rate (MFDR) in the glottis is known to correlate strongly with vocal intensity in voicing. This declination, or negative slope on the glottal airflow waveform, is in part attributable to the maximum area declination rate (MADR) and in part to the overall inertia of the air column of the vocal tract (lungs to…

  10. Nitric oxide flow tagging in unseeded air.

    PubMed

    Dam, N; Klein-Douwel, R J; Sijtsema, N M; Meulen, J J

    2001-01-01

    A scheme for molecular tagging velocimetry is presented that can be used in air flows without any kind of seeding. The method is based on the local and instantaneous creation of nitric oxide (NO) molecules from N(2) and O(2) in the waist region of a focused ArF excimer laser beam. This NO distribution is advected by the flow and can be visualized any time later by laser-induced fluorescence in the gamma bands. The creation of NO is confirmed by use of an excitation spectrum. Two examples of the application of the new scheme for air-flow velocimetry are given in which single laser pulses are used for creation and visualization of NO. PMID:18033499

  11. Development of an air flow thermal balance calorimeter

    NASA Technical Reports Server (NTRS)

    Sherfey, J. M.

    1972-01-01

    An air flow calorimeter, based on the idea of balancing an unknown rate of heat evolution with a known rate of heat evolution, was developed. Under restricted conditions, the prototype system is capable of measuring thermal wattages from 10 milliwatts to 1 watt, with an error no greater than 1 percent. Data were obtained which reveal system weaknesses and point to modifications which would effect significant improvements.

  12. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Air flow measurement specifications. 89.414 Section 89.414 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement...

  13. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Air flow measurement specifications. 89.414 Section 89.414 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement...

  14. 93. TEMPERATURE AND FLOW RATE CONTROLS FOR SYSTEM 1 AND ...

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

    93. TEMPERATURE AND FLOW RATE CONTROLS FOR SYSTEM 1 AND SYSTEM 2, FACING WEST IN MECHANICAL EQUIPMENT ROOM (101), LSB (BLDG. 770) - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  15. A MEMS-Based Flow Rate and Flow Direction Sensing Platform with Integrated Temperature Compensation Scheme.

    PubMed

    Ma, Rong-Hua; Wang, Dung-An; Hsueh, Tzu-Han; Lee, Chia-Yen

    2009-01-01

    This study develops a MEMS-based low-cost sensing platform for sensing gas flow rate and flow direction comprising four silicon nitride cantilever beams arranged in a cross-form configuration, a circular hot-wire flow meter suspended on a silicon nitride membrane, and an integrated resistive temperature detector (RTD). In the proposed device, the flow rate is inversely derived from the change in the resistance signal of the flow meter when exposed to the sensed air stream. To compensate for the effects of the ambient temperature on the accuracy of the flow rate measurements, the output signal from the flow meter is compensated using the resistance signal generated by the RTD. As air travels over the surface of the cross-form cantilever structure, the upstream cantilevers are deflected in the downward direction, while the downstream cantilevers are deflected in the upward direction. The deflection of the cantilever beams causes a corresponding change in the resistive signals of the piezoresistors patterned on their upper surfaces. The amount by which each beam deflects depends on both the flow rate and the orientation of the beam relative to the direction of the gas flow. Thus, following an appropriate compensation by the temperature-corrected flow rate, the gas flow direction can be determined through a suitable manipulation of the output signals of the four piezoresistors. The experimental results have confirmed that the resulting variation in the output signals of the integrated sensors can be used to determine not only the ambient temperature and the velocity of the air flow, but also its direction relative to the sensor with an accuracy of ± 7.5° error. PMID:22346708

  16. A MEMS-Based Flow Rate and Flow Direction Sensing Platform with Integrated Temperature Compensation Scheme

    PubMed Central

    Ma, Rong-Hua; Wang, Dung-An; Hsueh, Tzu-Han; Lee, Chia-Yen

    2009-01-01

    This study develops a MEMS-based low-cost sensing platform for sensing gas flow rate and flow direction comprising four silicon nitride cantilever beams arranged in a cross-form configuration, a circular hot-wire flow meter suspended on a silicon nitride membrane, and an integrated resistive temperature detector (RTD). In the proposed device, the flow rate is inversely derived from the change in the resistance signal of the flow meter when exposed to the sensed air stream. To compensate for the effects of the ambient temperature on the accuracy of the flow rate measurements, the output signal from the flow meter is compensated using the resistance signal generated by the RTD. As air travels over the surface of the cross-form cantilever structure, the upstream cantilevers are deflected in the downward direction, while the downstream cantilevers are deflected in the upward direction. The deflection of the cantilever beams causes a corresponding change in the resistive signals of the piezoresistors patterned on their upper surfaces. The amount by which each beam deflects depends on both the flow rate and the orientation of the beam relative to the direction of the gas flow. Thus, following an appropriate compensation by the temperature-corrected flow rate, the gas flow direction can be determined through a suitable manipulation of the output signals of the four piezoresistors. The experimental results have confirmed that the resulting variation in the output signals of the integrated sensors can be used to determine not only the ambient temperature and the velocity of the air flow, but also its direction relative to the sensor with an accuracy of ± 7.5° error. PMID:22346708

  17. Effect of wind tunnel air velocity on VOC flux rates from CAFO manure and wastewater

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind tunnels and flux chambers are often used to estimate volatile organic compound (VOC) emissions from animal feeding operations (AFOs) without regard to air velocity or sweep air flow rates. Laboratory experiments were conducted to evaluate the effect of wind tunnel air velocity on VOC emission ...

  18. Review of air flow measurement techniques

    SciTech Connect

    McWilliams, Jennifer

    2002-12-01

    Airflow measurement techniques are necessary to determine the most basic of indoor air quality questions: ''Is there enough fresh air to provide a healthy environment for the occupants of the building?'' This paper outlines airflow measurement techniques, but it does not make recommendations for techniques that should be used. The airflows that will be discussed are those within a room or zone, those between rooms or zones, such as through doorways (open or closed) or passive vents, those between the building and outdoors, and those through mechanical air distribution systems. Techniques that are highlighted include particle streak velocimetry, hot wire anemometry, fan pressurization (measuring flow at a given pressure), tracer gas, acoustic methods for leak size determination, the Delta Q test to determine duct leakage flows, and flow hood measurements. Because tracer gas techniques are widely used to measure airflow, this topic is broken down into sections as follows: decay, pulse injection, constant injection, constant concentration, passive sampling, and single and multiple gas measurements for multiple zones.

  19. Optical Air Flow Measurements for Flight Tests and Flight Testing Optical Air Flow Meters

    NASA Technical Reports Server (NTRS)

    Jentink, Henk W.; Bogue, Rodney K.

    2005-01-01

    Optical air flow measurements can support the testing of aircraft and can be instrumental to in-flight investigations of the atmosphere or atmospheric phenomena. Furthermore, optical air flow meters potentially contribute as avionics systems to flight safety and as air data systems. The qualification of these instruments for the flight environment is where we encounter the systems in flight testing. An overview is presented of different optical air flow measurement techniques applied in flight and what can be achieved with the techniques for flight test purposes is reviewed. All in-flight optical airflow velocity measurements use light scattering. Light is scattered on both air molecules and aerosols entrained in the air. Basic principles of making optical measurements in flight, some basic optical concepts, electronic concepts, optoelectronic interfaces, and some atmospheric processes associated with natural aerosols are reviewed. Safety aspects in applying the technique are shortly addressed. The different applications of the technique are listed and some typical examples are presented. Recently NASA acquired new data on mountain rotors, mountain induced turbulence, with the ACLAIM system. Rotor position was identified using the lidar system and the potentially hazardous air flow profile was monitored by the ACLAIM system.

  20. Optimum design of bipolar plates for separate air flow cooling system of PEM fuel cells stacks

    NASA Astrophysics Data System (ADS)

    Franco, Alessandro

    2015-12-01

    The paper discusses about thermal management of PEM fuel cells. The objective is to define criteria and guidelines for the design of the air flow cooling system of fuel cells stacks for different combination of power density, bipolar plates material, air flow rate, operating temperature It is shown that the optimization of the geometry of the channel permits interesting margins for maintaining the use of separate air flow cooling systems for high power density PEM fuel cells.

  1. Flow Rate Measurements Using Flow-Induced Pipe Vibration

    SciTech Connect

    R. P. Evans; Jonathan D. Blotter; Alan G. Stephens

    2004-03-01

    This paper focuses on the possibility of a non-intrusive, low cost, flow rate measurement technique. The technique is based on signal noise from an accelerometer attached to the surface of the pipe. The signal noise is defined as the standard deviation of the frequency averaged time series signal. Experimental results are presented that indicate a nearly quadratic relationship between the signal noise and mass flow rate in the pipe. It is also shown that the signal noise - flow rate relationship is dependant on the pipe material and diameter.

  2. Flow rate limitation in open capillary channel flows.

    PubMed

    Haake, Dennis; Rosendahl, Uwe; Ohlhoff, Antje; Dreyer, Michael E

    2006-09-01

    This paper reports the experimental and theoretical investigations of forced liquid flows through open capillary channels under reduced gravity conditions. An open capillary channel is a structure that establishes a liquid flow path at low Bond numbers, when the capillary pressure caused by the surface tension force dominates in comparison to the hydrostatic pressure induced by gravitational or residual accelerations. In case of steady flow through the channel, the capillary pressure of the free surface balances the pressure difference between the liquid and the surrounding constant-pressure gas phase. Because of convective and viscous momentum transport, the pressure along the flow path decreases and causes the free surface to bend inward. The maximum flow rate is achieved when the free surface collapses and gas ingestion occurs at the outlet. This critical flow rate depends on the geometry of the channel and the properties of the liquid. In this paper we present a comparison of the theoretical and experimental critical flow rates and surface profiles for convective dominated flows. For the prediction of the critical flow rate a one-dimensional theoretical model taking into account the entrance pressure loss and the frictional pressure loss in the channel is developed. PMID:17124140

  3. Properties of a constricted-tube air-flow levitator

    NASA Technical Reports Server (NTRS)

    Rush, J. E.; Stephens, W. K.; Ethridge, E. C.

    1982-01-01

    The properties of a constricted-tube gas flow levitator first developed by Berge et al. (1981) have been investigated experimentally in order to predict its behavior in a gravity-free environment and at elevated temperatures. The levitator consists of a constricted (quartz) tube fed at one end by a source of heated air or gas. A spherical sample is positioned by the air stream on the downstream side of the constriction, where it can be melted and resolidified without touching the tube. It is shown experimentally that the kinematic viscosity is the important fluid parameter for operation in thermal equilibrium at high temperatures. If air is heated from room temperature to 1200 C, the kinematic viscosity increases by a factor of 14. To maintain a given value of the Reynolds number, the flow rate would have to be increased by the same factor for a specific geometry of tube and sample. Thus, to maintain stable equilibrium, the flow rate should be increased as the air or other gas is heated. The other stability problem discussed is associated with changes in the shape of a cylindrical sample as it melts.

  4. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Air flow measurement specifications. 89... Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement method used... during the test. Overall measurement accuracy must be ± 2 percent of the maximum engine value for...

  5. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Air flow measurement specifications... Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement method... during the test. Overall measurement accuracy must be ± 2 percent of the maximum engine value for...

  6. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Air flow measurement specifications... Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement method... during the test. Overall measurement accuracy must be ± 2 percent of the maximum engine value for...

  7. 40 CFR 90.416 - Intake air flow measurement specifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Intake air flow measurement... Gaseous Exhaust Test Procedures § 90.416 Intake air flow measurement specifications. (a) If used, the engine intake air flow measurement method used must have a range large enough to accurately measure...

  8. Historical river flow rates for dose calculations

    SciTech Connect

    Carlton, W.H.

    1991-06-10

    Annual average river flow rates are required input to the LADTAP Computer Code for calculating offsite doses from liquid releases of radioactive materials to the Savannah River. The source of information on annual river flow rates used in dose calculations varies, depending on whether calculations are for retrospective releases or prospective releases. Examples of these types of releases are: Retrospective - releases from routine operations (annual environmental reports) and short term release incidents that have occurred. Prospective - releases that might be expected in the future from routine or abnormal operation of existing or new facilities (EIS`s, EID`S, SAR`S, etc.). This memorandum provides historical flow rates at the downstream gauging station at Highway 301 for use in retrospective dose calculations and derives flow rate data for the Beaufort-Jasper and Port Wentworth water treatment plants.

  9. On the impact of entrapped air in infiltration under ponding conditions: Part a: Preferential air flow path effects on infiltration

    NASA Astrophysics Data System (ADS)

    Weisbord, N.; Mizrahi, G.; Furman, A.

    2015-12-01

    Entrapped air effects on infiltration under ponding conditions could be important for massive infiltration of managed aquifer recharge or soil aquifer treatment. Earlier studies found that under ponding conditions air could reduce infiltration by 70-90%. Most studies have dealt with entrapped air effects when soil surface topography is flat. The objective of this study is to investigate the effects of: (1) irregular surface topography on preferential air flow path development; (2) preferential air flow path on infiltration; and (3) hydraulic head on infiltration when air is trapped. Column experiments were used to investigate these particular effects. A 140 cm deep and 30 cm wide column packed with silica sand was used under two boundary conditions: in the first, air can only escape vertically upward through the soil surface; in the second, air is free to escape. The surface was flooded with 13 liters of water, with ponding depth decreasing with time. Two soil surface conditions were tested: flat surface and irregular. It was found that in irregular surfaces, stable air flow through preferential paths was developed in the high altitude zones. Flat surface topography caused unstable air flow through random paths. Comparison between irregular and flat surface topography showed that the entrapped air pressure was lower and the infiltration rate was about 40% higher in the irregular surface topography than in the flat surface topography. No difference of infiltration rate between flat and irregular surface topography was observed when air was free to escape along the infiltration path. It was also found that at the first stage of infiltration, higher hydraulic heads caused higher entrapped air pressures and lower infiltration rates. In contrast, higher hydraulic head results in higher infiltration rate, when air was free to escape. Our results suggest that during ponding conditions: (1) preferential air flow paths develop at high surface zones of irregular topography

  10. Significances of the variability of airway paths and their air-flow rates to dosimetry model predictions of the absorption of gases

    SciTech Connect

    Overton, J.H.; Barnett, A.E.; Graham, R.C.

    1987-12-01

    The ozone-dosimetry model developed at EPA was developed to be used in conjunction with species lung models that summarize the structure of a lung as a lung of many equivalent paths. The paper reports the results of a preliminary study into the question of whether or not more realistic lung structures and airflow rates in individual airways need to be taken into account in order to make more-accurate predictions of ozone uptake. The results indicate that in order to obtain a better understanding of the distribution of absorbed ozone in the lower respiratory tract (LRT), realistic lung structures need to be taken into account. Whereas, estimating LRT dose using a lung model composed of equivalent paths was found to give the same results obtained as when the complex lung structure was taken into account. The information will allow for a better use of experimental uptake data for the evaluation of dosimetry model predictions as well as for improved interpreting of toxicological data.

  11. Stability of flow focusing: The minimum attainable flow rate

    NASA Astrophysics Data System (ADS)

    Montanero, J. M.; Rebollo, N.; Acero, A.; Ferrera, C.; Herrada, M. A.; Ganan-Calvo, A. M.

    2011-11-01

    We analyze both theoretically and experimentally the stability of the steady jetting regime reached when liquid jets are focused by coaxial gas streams. In the low-viscosity case, viscous dissipation in the feeding capillary and liquid meniscus seem to be the origin of the instability. For high-viscosity liquids, the breakdown of the jetting regime takes place when the pressure drop cannot overcome the resistance force offered by surface tension. The characteristic flow rates for which the tapering menisci become unstable do not depend on the pressure drop applied to the system to produce the micro-jet. They increase (decrease) with viscosity for very low (high) viscosity liquids. Experiments confirmed the validity of the above conclusions. For each applied pressure drop, there is a minimum liquid flow rate below which the liquid meniscus drips. The minimum flow rates become practically independent of the applied pressure drop for sufficiently large values of this quantity. There exists an optimum value of the capillary-to-orifice distance for which the minimum flow rate attains a limiting value, which constitutes the lowest flow rate attainable with a given configuration in the steady jetting regime. A two-dimensional stability map with a high degree of validity is plotted on the plane defined by the Reynolds and capillary numbers based on the limiting flow rate.

  12. Review of Air Exchange Rate Models for Air Pollution Exposure Assessments

    EPA Science Inventory

    A critical aspect of air pollution exposure assessments is estimation of the air exchange rate (AER) for various buildings, where people spend their time. The AER, which is rate the exchange of indoor air with outdoor air, is an important determinant for entry of outdoor air pol...

  13. New sensor for measurement of low air flow velocity. Phase I final report

    SciTech Connect

    Hashemian, H.M.; Hashemian, M.; Riggsbee, E.T.

    1995-08-01

    The project described here is the Phase I feasibility study of a two-phase program to integrate existing technologies to provide a system for determining air flow velocity and direction in radiation work areas. Basically, a low air flow sensor referred to as a thermocouple flow sensor has been developed. The sensor uses a thermocouple as its sensing element. The response time of the thermocouple is measured using an existing in-situ method called the Loop Current Step Response (LCSR) test. The response time results are then converted to a flow signal using a response time-versus-flow correlation. The Phase I effort has shown that a strong correlation exists between the response time of small diameter thermocouples and the ambient flow rate. As such, it has been demonstrated that thermocouple flow sensors can be used successfully to measure low air flow rates that can not be measured with conventional flow sensors. While the thermocouple flow sensor developed in this project was very successful in determining air flow velocity, determining air flow direction was beyond the scope of the Phase I project. Nevertheless, work was performed during Phase I to determine how the new flow sensor can be used to determine the direction, as well as the velocity, of ambient air movements. Basically, it is necessary to use either multiple flow sensors or move a single sensor in the monitoring area and make flow measurements at various locations sweeping the area from top to bottom and from left to right. The results can then be used with empirical or physical models, or in terms of directional vectors to estimate air flow patterns. The measurements can be made continuously or periodically to update the flow patterns as they change when people and objects are moved in the monitoring area. The potential for using multiple thermocouple flow sensors for determining air flow patterns will be examined in Phase II.

  14. Ultrasonic rate measurement of multiphase flow

    SciTech Connect

    Dannert, D.A.; Horne, R.N.

    1993-01-01

    On of the most important tools in production logging and well testing is the downhole flowmeter. Unfortunately, existing tools are inaccurate outside of an idealized single phase flow, regime. Spinner tools are inaccurate at extremely high or low, flow rates and when the flow rate is variable. Radioactive tracer tools have similar inaccuracies and are extremely sensitive to the flow regime. Both tools completely fail in the presence of multiphase flow, whether gas/ oil, gas/water or fluid/solid. Downhole flowmetering is important for locating producing zones and thief zones and monitoring production and injection rates. The effects of stimulation can also be determined. This goal of this project is the investigation of accurate downhole flowmetering techniques for all single phase flow regimes and multiphase flows. The measurement method investigated in this report is the use of ultrasound. There are two ways to use ultrasound for fluid velocity measurement. The first method, examined in Chapter 2, is the contrapropagation, or transit-time, method which compares travel times with and against fluid flow. Chapter 3 details the second method which measures the Doppler frequency shift of a reflected sound wave in the moving fluid. Both of these technologies need to be incorporated in order to build a true multiphase flowmeter. Chapter 4 describes the proposed downhole multiphase flowmeter. It has many advantages besides the ones previously mentioned and is in full in that chapter.

  15. Ultrasonic rate measurement of multiphase flow

    NASA Astrophysics Data System (ADS)

    Dannert, David A.; Horne, Roland N.

    1993-01-01

    One of the most important tools in production logging and well testing is the downhole flowmeter. Unfortunately, existing tools are inaccurate outside of an idealized single phase flow regime. Spinner tools are inaccurate at extremely high or low flow rates and when the flow rate is variable. Radioactive tracer tools have similar inaccuracies and are extremely sensitive to the flow regime. Both tools completely fail in the presence of multiphase flow, whether for gas/oil, gas/water, or fluid/solid. Downhole flowmetering is important for locating producing zones and thief zones and monitoring production and injection rates. The effects of stimulation can also be determined. The goal of this project is the investigation of accurate downhole flowmetering techniques for all single phase flow regimes and multiphase flows. The measurement method investigated in this report is the use of ultrasound. There are two ways to use ultrasound for fluid velocity measurement. The first method, examined in Chapter 2, is the contrapropagation, or transit-time, method which compares travel times with and against fluid flow. Chapter 3 details the second method which measures the Doppler frequency shift of a reflected sound wave in the moving fluid. Both of these technologies need to be incorporated in order to build a true multiphase flowmeter. Chapter 4 describes the proposed downhole multiphase flowmeter.

  16. DEVELOPMENT OF A LOW PRESSURE, AIR ATOMIZED OIL BURNER WITH HIGH ATOMIZER AIR FLOW

    SciTech Connect

    BUTCHER,T.A.

    1998-01-01

    This report describes technical advances made to the concept of a low pressure, air atomized oil burner for home heating applications. Currently all oil burners on the market are of the pressure atomized, retention head type. These burners have a lower firing rate limit of about 0.5 gallons per hour of oil, due to reliability problems related to small flow passage sizes. High pressure air atomized burners have been shown to be one route to avoid this problem but air compressor cost and reliability have practically eliminated this approach. With the low pressure air atomized burner the air required for atomization can be provided by a fan at 5--8 inches of water pressure. A burner using this concept, termed the Fan-Atomized Burner or FAB has been developed and is currently being commercialized. In the head of the FAB, the combustion air is divided into three parts, much like a conventional retention head burner. This report describes development work on a new concept in which 100% of the air from the fan goes through the atomizer. The primary advantage of this approach is a great simplification of the head design. A nozzle specifically sized for this concept was built and is described in the report. Basic flow pressure tests, cold air velocity profiles, and atomization performance have been measured. A burner head/flame tube has been developed which promotes a torroidal recirculation zone near the nozzle for flame stability. The burner head has been tested in several furnace and boiler applications over the tiring rate range 0.2 to 0.28 gallons per hour. In all cases the burner can operate with very low excess air levels (under 10%) without producing smoke. Flue gas NO{sub x} concentration varied from 42 to 62 ppm at 3% 0{sub 2}. The concept is seen as having significant potential and planned development efforts are discussed.

  17. Flow measurement in base cooling air passages of a rotating turbine blade

    NASA Technical Reports Server (NTRS)

    Liebert, C. H.; Pollack, F. G.

    1974-01-01

    The operational performance is decribed of a shaft-mounted system for measuring the air mass flow rate in the base cooling passages of a rotating turbine blade. Shaft speeds of 0 to 9000 rpm, air mass flow rates of 0.0035 to 0.039 kg/sec (0.0077 to 0.085 lbm/sec), and blade air temperatures of 300 to 385 K (80 to 233 F) were measured. Comparisons of individual rotating blade flows and corresponding stationary supply orifice flows agreed to within 10 percent.

  18. Decentralized and Tactical Air Traffic Flow Management

    NASA Technical Reports Server (NTRS)

    Bertsimas, Dimitris; Odoni, Amedeo R.

    1997-01-01

    This project dealt with the following topics: 1. Review and description of the existing air traffic flow management system (ATFM) and identification of aspects with potential for improvement. 2. Identification and review of existing models and simulations dealing with all system segments (enroute, terminal area, ground) 3. Formulation of concepts for overall decentralization of the ATFM system, ranging from moderate decentralization to full decentralization 4. Specification of the modifications to the ATFM system required to accommodate each of the alternative concepts. 5. Identification of issues that need to be addressed with regard to: determination of the way the ATFM system would be operating; types of flow management strategies that would be used; and estimation of the effectiveness of ATFM with regard to reducing delay and re-routing costs. 6. Concept evaluation through identification of criteria and methodologies for accommodating the interests of stakeholders and of approaches to optimization of operational procedures for all segments of the ATFM system.

  19. Combustor air flow control method for fuel cell apparatus

    DOEpatents

    Clingerman, Bruce J.; Mowery, Kenneth D.; Ripley, Eugene V.

    2001-01-01

    A method for controlling the heat output of a combustor in a fuel cell apparatus to a fuel processor where the combustor has dual air inlet streams including atmospheric air and fuel cell cathode effluent containing oxygen depleted air. In all operating modes, an enthalpy balance is provided by regulating the quantity of the air flow stream to the combustor to support fuel cell processor heat requirements. A control provides a quick fast forward change in an air valve orifice cross section in response to a calculated predetermined air flow, the molar constituents of the air stream to the combustor, the pressure drop across the air valve, and a look up table of the orifice cross sectional area and valve steps. A feedback loop fine tunes any error between the measured air flow to the combustor and the predetermined air flow.

  20. Air exchange rates in new energy-efficient manufactured housing

    SciTech Connect

    Hadley, D.; Bailey, S.

    1990-10-01

    During the 1989--1990 heating season, Pacific Northwest Laboratory, for the Bonneville Power Administration, measured the ventilation characteristics of 139 newly constructed energy-efficient manufactured homes and a control sample of 35 newer manufactured homes. A standard door fan pressurization technique was used to estimate shell leakiness, and a passive perfluorocarbon tracer technique was used to estimate overall air exchange rates. A measurement of the designated whole-house exhaust system flow rate was taken as well as an occupant and structure survey. The energy-efficient manufactured homes have very low air exchange rates, significantly lower than either existing manufactured homes or site-built homes. The standard deviation of the effective leakage area for this sample of homes is small (25% to 30% of the mean), indicating that the leakiness of manufactured housing stock can be confidently characterized by the mean value. There is some indication of increased ventilation due to the energy-efficient whole-house ventilation specification, but not directly related to the operation of the whole-house system. The mechanical systems as installed and operated do not provide the intended ventilation; consequently indoor air quality could possibly be adversely impacted and moisture/condensation in the living space is a potential problem. 6 refs., 6 figs., 5 tabs.

  1. Cold air performance of a 12.766-centimeter-tip-diameter axial-flow cooled turbine. 2: Effect of air ejection on turbine performance

    NASA Technical Reports Server (NTRS)

    Haas, J. E.; Kofskey, M. G.

    1977-01-01

    An air cooled version of a single-stage, axial-flow turbine was investigated to determine aerodynamic performance with and without air ejection from the stator and rotor blades surfaces to simulate the effect of cooling air discharge. Air ejection rate was varied from 0 to 10 percent of turbine mass flow for both the stator and the rotor. A primary-to-air ejection temperature ratio of about 1 was maintained.

  2. Dynamic Flow Management Problems in Air Transportation

    NASA Technical Reports Server (NTRS)

    Patterson, Sarah Stock

    1997-01-01

    In 1995, over six hundred thousand licensed pilots flew nearly thirty-five million flights into over eighteen thousand U.S. airports, logging more than 519 billion passenger miles. Since demand for air travel has increased by more than 50% in the last decade while capacity has stagnated, congestion is a problem of undeniable practical significance. In this thesis, we will develop optimization techniques that reduce the impact of congestion on the national airspace. We start by determining the optimal release times for flights into the airspace and the optimal speed adjustment while airborne taking into account the capacitated airspace. This is called the Air Traffic Flow Management Problem (TFMP). We address the complexity, showing that it is NP-hard. We build an integer programming formulation that is quite strong as some of the proposed inequalities are facet defining for the convex hull of solutions. For practical problems, the solutions of the LP relaxation of the TFMP are very often integral. In essence, we reduce the problem to efficiently solving large scale linear programming problems. Thus, the computation times are reasonably small for large scale, practical problems involving thousands of flights. Next, we address the problem of determining how to reroute aircraft in the airspace system when faced with dynamically changing weather conditions. This is called the Air Traffic Flow Management Rerouting Problem (TFMRP) We present an integrated mathematical programming approach for the TFMRP, which utilizes several methodologies, in order to minimize delay costs. In order to address the high dimensionality, we present an aggregate model, in which we formulate the TFMRP as a multicommodity, integer, dynamic network flow problem with certain side constraints. Using Lagrangian relaxation, we generate aggregate flows that are decomposed into a collection of flight paths using a randomized rounding heuristic. This collection of paths is used in a packing integer

  3. Electromagnetic flow rate meter. [for liquid metals

    NASA Technical Reports Server (NTRS)

    Banks, B. A. (Inventor)

    1974-01-01

    A liquid metal, whose flow rate is to be determined, is directed through a chamber made of electrically-insulating material on which there is impressed a magnetic field perpendicular to the direction of flow of the liquid metal. The magnetic field is made to increase in strength in a downstream direction of the flow of liquid metal. At least a pair of electrodes are disposed in the chamber traversely and perpendicular to the direction of flow and an ammeter is connected between the electrodes. Electrodes may be disposed in the top or the bottom of the chamber and each may be segmented. Oppositely disposed electrodes may be used with at least one dividing wall extending from each electrode to cause reversal of the direction of flow of the liquid metal. The magnetic field may be provided by electromagnets or permanent magnets such as shaded pole permanent magnets.

  4. Reserve, flowing electrolyte, high rate lithium battery

    NASA Astrophysics Data System (ADS)

    Puskar, M.; Harris, P.

    Flowing electrolyte Li/SOCl2 tests in single cell and multicell bipolar fixtures have been conducted, and measurements are presented for electrolyte flow rates, inlet and outlet temperatures, fixture temperatures at several points, and the pressure drop across the fixture. Reserve lithium batteries with flowing thionyl-chloride electrolytes are found to be capable of very high energy densities with usable voltages and capacities at current densities as high as 500 mA/sq cm. At this current density, a battery stack 10 inches in diameter is shown to produce over 60 kW of power while maintaining a safe operating temperature.

  5. Effects of energy-efficient ventilation rates on indoor air quality at an Ohio elementary school

    NASA Astrophysics Data System (ADS)

    Berk, J. V.; Young, R.; Hollowell, C. D.; Turiel, I.; Pepper, J.

    1980-04-01

    A mobile laboratory was used to monitor air outdoors and at three indoor sites (two classrooms and a large multipurpose room); tests were made at three different ventilation rates. The parameters measured were outside air flow rates, odor perception, microbial burden, particulate mass, total aldehydes, carbon dioxide, ozone, and nitrogen oxides. The results of these measurements are given and compared with the existing outdoor air quality standards. Carbon dioxide concentrations increased as the ventilation rate decreased, but still did not exceed current standards. Odor perceptibility increased slightly at the lowest ventilation rate. Other pollutants showed very low concentrations, which did not change with reductions in ventilation rate.

  6. Changes in air flow patterns using surfactants and thickeners during air sparging: Bench-scale experiments

    NASA Astrophysics Data System (ADS)

    Kim, Juyoung; Kim, Heonki; Annable, Michael D.

    2015-01-01

    Air injected into an aquifer during air sparging normally flows upward according to the pressure gradients and buoyancy, and the direction of air flow depends on the natural hydrogeologic setting. In this study, a new method for controlling air flow paths in the saturated zone during air sparging processes is presented. Two hydrodynamic parameters, viscosity and surface tension of the aqueous phase in the aquifer, were altered using appropriate water-soluble reagents distributed before initiating air sparging. Increased viscosity retarded the travel velocity of the air front during air sparging by modifying the viscosity ratio. Using a one-dimensional column packed with water-saturated sand, the velocity of air intrusion into the saturated region under a constant pressure gradient was inversely proportional to the viscosity of the aqueous solution. The air flow direction, and thus the air flux distribution was measured using gaseous flux meters placed at the sand surface during air sparging experiments using both two-, and three-dimensional physical models. Air flow was found to be influenced by the presence of an aqueous patch of high viscosity or suppressed surface tension in the aquifer. Air flow was selective through the low-surface tension (46.5 dyn/cm) region, whereas an aqueous patch of high viscosity (2.77 cP) was as an effective air flow barrier. Formation of a low-surface tension region in the target contaminated zone in the aquifer, before the air sparging process is inaugurated, may induce air flow through the target zone maximizing the contaminant removal efficiency of the injected air. In contrast, a region with high viscosity in the air sparging influence zone may minimize air flow through the region prohibiting the region from de-saturating.

  7. Experimental verification of the four-sensor probe model for flow diagnosis in air water flow in vertical pipe

    NASA Astrophysics Data System (ADS)

    Pradhan, S.; Mishra, R.

    2012-05-01

    Measuring the volumetric flow rate of each of the flowing components is required to be monitored in production logging applications. Hence it is necessary to measure the flow rates of gas, oil and water in vertical and inclined oil wells. An increasing level of interest has been shown by the researchers in developing system for the flow rate measurement in multiphase flows. This paper describes the experimental methodology using a miniature, local four-sensor probe for the measurement of dispersed flow parameters in bubbly two-phase flow for spherical bubbles. To establish interdependent among different parameters corresponding to dispersed flow, the available model has been used to experimentally obtain different parameters such as volume fraction, velocity and bubble shape of the dispersed phase in the bubbly air-water flow.

  8. A model for reaction rates in turbulent reacting flows

    NASA Technical Reports Server (NTRS)

    Chinitz, W.; Evans, J. S.

    1984-01-01

    To account for the turbulent temperature and species-concentration fluctuations, a model is presented on the effects of chemical reaction rates in computer analyses of turbulent reacting flows. The model results in two parameters which multiply the terms in the reaction-rate equations. For these two parameters, graphs are presented as functions of the mean values and intensity of the turbulent fluctuations of the temperature and species concentrations. These graphs will facilitate incorporation of the model into existing computer programs which describe turbulent reacting flows. When the model was used in a two-dimensional parabolic-flow computer code to predict the behavior of an experimental, supersonic hydrogen jet burning in air, some improvement in agreement with the experimental data was obtained in the far field in the region near the jet centerline. Recommendations are included for further improvement of the model and for additional comparisons with experimental data.

  9. Numerical Simulation of Two-phase Flow in a Microchannel with Air Gap

    NASA Astrophysics Data System (ADS)

    Liu, Xiaojun; Meinhart, Carl D.

    2001-11-01

    Fluid transport in nano- and micro-scale devices becomes more and more important. The potential advantages of micro-channel with air gap are studied. A simple one-dimensional model of air-water two-phase flow is investigated theoretically. The flow of water is driven by pressure drop. The air in the gap is driven by surface tension and friction forces that exist at the interface between the water and air. With the limitation that air flow rate is zero, the theoretical results are obtained based on continuity and Navier-Stokes equations. Because the viscosity of air is much less than that of water, under same pressure drop, the flow rate of water can be increased to as 4.76 times as that of normal channel without air gap. The theoretical results are tested by numerical simulation with three different software package (CFD2000, FEMLab and CFDRC) using a two-dimensional model. The interface shape, interface velocity, water flow rate and optimum height ratio are studied. Thenumerical results for different package match each other very well. The numerical results show that increasing water flow rate by adding air gap in the micro channel is practicable.

  10. Controlling a wide range of flow rates

    NASA Technical Reports Server (NTRS)

    Perkins, G. S.

    1979-01-01

    Servo-operated valve and two flowmeters allow accurate control over 1,900:1 flow-rate range. It was developed as part of laboratory instrument for measuring properties of confined fluids under conditions analogous to those encountered in deep drilling operations.

  11. Rates of Flow: Some Useful Equations.

    ERIC Educational Resources Information Center

    Robertson, I. S.

    1979-01-01

    Presents a step-by-step approach to be used in solving different forms of physics problems, starting from familiar grounds and finding well known results on the way. Uses the rate of heat flow and the resulting changes of temperature with time of a copper block as an example. (GA)

  12. Surface-slip equations for multicomponent, nonequilibrium air flow

    NASA Technical Reports Server (NTRS)

    Gupta, Roop N.; Scott, Carl D.; Moss, James N.; Goglia, Gene

    1985-01-01

    Equations are presented for the surface slip (or jump) values of species concentration, pressure, velocity, and temperature in the low-Reynolds-number, high-altitude flight regime of a space vehicle. These are obtained from closed-form solutions of the mass, momentum, and energy flux equations using the Chapman-Enskog velocity distribution function. This function represents a solution of the Boltzmann equation in the Navier-Stokes approximation. The analysis, obtained for nonequilibrium multicomponent air flow, includes the finite-rate surface catalytic recombination and changes in the internal energy during reflection from the surface. Expressions for the various slip quantities have been obtained in a form which can readily be employed in flow-field computations. A consistent set of equations is provided for multicomponent, binary, and single species mixtures. Expression is also provided for the finite-rate species-concentration boundary condition for a multicomponent mixture in absence of slip.

  13. Prototype Systems for Measuring Outdoor Air Intake Rates in Rooftop Air Handlers

    SciTech Connect

    Fisk, William J.; Chan, Wanyu R.; Hotchi, Toshifumi

    2015-01-01

    The widespread absence of systems for real-time measurement and feedback control, of minimum outdoor air intake rates in HVAC systems contributes to the poor control of ventilation rates in commercial buildings. Ventilation rates affect building energy consumption and influence occupant health. The project designed fabricated and tested four prototypes of systems for measuring rates of outdoor air intake into roof top air handlers. All prototypes met the ±20% accuracy target at low wind speeds, with all prototypes accurate within approximately ±10% after application of calibration equations. One prototype met the accuracy target without a calibration. With two of four prototype measurement systems, there was no evidence that wind speed or direction affected accuracy; however, winds speeds were generally below usually 3.5 m s-1 (12.6 km h-1) and further testing is desirable. The airflow resistance of the prototypes was generally less than 35 Pa at maximum RTU air flow rates. A pressure drop of this magnitude will increase fan energy consumption by approximately 4%. The project did not have resources necessary to estimate costs of mass produced systems. The retail cost of components and materials used to construct prototypes ranged from approximately $1,200 to $1,700. The test data indicate that the basic designs developed in this project, particularly the designs of two of the prototypes, have considerable merit. Further design refinement, testing, and cost analysis would be necessary to fully assess commercial potential. The designs and test results will be communicated to the HVAC manufacturing community.

  14. Femtosecond laser flow tagging in non-air flows

    NASA Astrophysics Data System (ADS)

    Zhang, Yibin; Calvert, Nathan

    2015-11-01

    The Femtosecond Laser Electronic Excitation Tagging (FLEET) [Michael, J. B. et al., Applied optics, 50(26), 2011] method is studied in nitrogen-containing gaseous flows. The underlying mechanism behind the FLEET process is the dissociation of molecular nitrogen into atomic nitrogen, which produces long-lived florescence as the nitrogen atoms recombine. Spectra and images of the resulting tagged line provide insight into the effects of different atmospheric gases on the FLEET process. The ionization cross-section, conductivity and energy states of the gaseous particles are each brought into consideration. These experiments demonstrate the feasibility for long-lived flow tagging on the order of hundreds of microseconds in non-air environments. Of particular interest are the enhancement of the FLEET signal with the addition of argon gas, and the non-monotonic quenching effect of oxygen on the length, duration and intensity of the resulting signal and spectra. FLEET is characterized in number of different atmospheric gases, including that simulating Mar's atmospheric composition.

  15. A Review of the Thermodynamic, Transport, and Chemical Reaction Rate Properties of High-temperature Air

    NASA Technical Reports Server (NTRS)

    Hansen, C Frederick; Heims, Steve P

    1958-01-01

    Thermodynamic and transport properties of high temperature air, and the reaction rates for the important chemical processes which occur in air, are reviewed. Semiempirical, analytic expressions are presented for thermodynamic and transport properties of air. Examples are given illustrating the use of these properties to evaluate (1) equilibrium conditions following shock waves, (2) stagnation region heat flux to a blunt high-speed body, and (3) some chemical relaxation lengths in stagnation region flow.

  16. Indoor air flow and pollutant removal in a room with desk-top ventilation

    SciTech Connect

    Faulkner, D.; Fisk, W.J.; Sullivan, D.P.

    1993-04-01

    In a furnished experimental facility with three workstations separated by partitions, we studied indoor air flow patterns and tobacco smoke removal efficiency of a desk-top task ventilation system. The task ventilation system permits occupant control of the temperature, flow rate and direction of air supplied through two desk-mounted supply nozzles. In the configuration evaluated, air exited the ventilated space through a ceiling-mounted return grill. To study indoor air flow patterns, we measured the age of air at multiple indoor locations using the tracer gas step-up procedure. To study the intra-room transport of tobacco smoke particles and the efficiency of panicle removal by ventilation, a cigarette was smoked mechanically in one workstation and particle concentrations were measured at multiple indoor locations including the exhaust airstream. Test variables included the direction of air supply from the nozzles, supply nozzle area, supply flow rate and temperature, percent recirculation of chamber air, and internal heatloads. With nozzles pointed toward the occupants, 100% outside air supplied at the desk-top, and air supply rates of approximately 40 L/s per workstation, the age of air at the breathing level of ventilated workstations was approximately 30% less than the age of air that would occur throughout the test space with perfectly mixed indoor air. With smaller air supply rates and/or air supplied parallel to the edges of the desk, ages of air at breathing locations were not significantly lower than the age with perfect mixing. Indoor tobacco smoke particle concentrations at specific locations were generally within 12% of the average measured indoor concentration and concentrations of particles in the exhaust airstream were not significantly different from concentration of particles at breathing locations.

  17. Current Problems and Issues in Air Freight Rates

    NASA Technical Reports Server (NTRS)

    Stout, A. R.

    1972-01-01

    Actions of the Civil Aeronautics Board in determining air freight rates are discussed. The tariff filings by domestic airlines for making basic changes in domestic fares and rates are reported. The roles of the carriers and the Civil Aeronautics Board in establishing freight rates are defined. Specific examples of areas of controversy in establishing freight rates are included. Methods for improving the air cargo and freight rate situation are proposed.

  18. A Study on the Air flow outside Ambient Vaporizer Fin

    NASA Astrophysics Data System (ADS)

    Oh, G.; Lee, T.; Jeong, H.; Chung, H.

    2015-09-01

    In this study, we interpreted Fog's Fluid that appear in the Ambient Vaporizer and predict the point of change Air to Fog. We interpreted using Analysis working fluid was applied to LNG and Air. We predict air flow when there is chill of LNG in the air Temperature and that makes fog. Also, we interpreted based on Summer and Winter criteria in the air temperature respectively. Finally, we can check the speed of the fog when fog excreted.

  19. Flow rate measurement in aggressive conductive fluids

    NASA Astrophysics Data System (ADS)

    Dubovikova, Nataliia; Kolesnikov, Yuri; Karcher, Christian

    2014-03-01

    Two non-contact experimental methods of flow rate measurements for aggressive conductive liquids are described. The techniques are based on electromagnetic forces and Faraday's law: Lorentz force is induced inside moving conductive liquid under influence of variable magnetic field of permanent magnets. They are mounted along a liquid metal channel or (in case of the second method) inserted into rotated metal wheels. The force acts in the opposite of fluids' velocity direction and hence it is possible to measure reaction force of it that takes place according to Newton's law on magnetic field source - permanent magnets. And by knowing the force, which linearly depends on velocity, one can calculate mean flow rate of liquid. In addition experimental "dry" calibration and its results are described for one of the measurements' techniques.

  20. Determining Seed Cotton Mass Flow Rate by Pressure Drop Across a Blowbox: Gin Testing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate measurement of the mass flow rate of seed cotton is needed for control and monitoring purposes in gins. A system was developed that accurately predicted mass flow rate based on the static pressure drop measured across the blowbox and the air velocity and temperature entering the blowbox. Ho...

  1. RESIDENTIAL AIR EXCHANGE RATES FOR USE IN INDOOR AIR AND EXPOSURE MODELING STUDIES

    EPA Science Inventory

    Data on air exchange rates are important inputs to indoor air quality models. ndoor air models, in turn, are incorporated into the structure of total human exposure models. ragmentary data on residential ventilation rates are available in various governmental reports, journal art...

  2. 40 CFR 1065.225 - Intake-air flow meter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Intake-air flow meter. 1065.225 Section 1065.225 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.225...

  3. 40 CFR 1065.225 - Intake-air flow meter.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Intake-air flow meter. 1065.225 Section 1065.225 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.225...

  4. 40 CFR 1065.225 - Intake-air flow meter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Intake-air flow meter. 1065.225 Section 1065.225 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.225...

  5. 40 CFR 1065.225 - Intake-air flow meter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Intake-air flow meter. 1065.225 Section 1065.225 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.225...

  6. 40 CFR 1065.225 - Intake-air flow meter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Intake-air flow meter. 1065.225 Section 1065.225 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.225...

  7. Particle displacement tracking applied to air flows

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.

    1991-01-01

    Electronic Particle Image Velocimeter (PIV) techniques offer many advantages over conventional photographic PIV methods such as fast turn around times and simplified data reduction. A new all electronic PIV technique was developed which can measure high speed gas velocities. The Particle Displacement Tracking (PDT) technique employs a single cw laser, small seed particles (1 micron), and a single intensified, gated CCD array frame camera to provide a simple and fast method of obtaining two-dimensional velocity vector maps with unambiguous direction determination. Use of a single CCD camera eliminates registration difficulties encountered when multiple cameras are used to obtain velocity magnitude and direction information. An 80386 PC equipped with a large memory buffer frame-grabber board provides all of the data acquisition and data reduction operations. No array processors of other numerical processing hardware are required. Full video resolution (640x480 pixel) is maintained in the acquired images, providing high resolution video frames of the recorded particle images. The time between data acquisition to display of the velocity vector map is less than 40 sec. The new electronic PDT technique is demonstrated on an air nozzle flow with velocities less than 150 m/s.

  8. Electromechanically Actuated Valve for Controlling Flow Rate

    NASA Technical Reports Server (NTRS)

    Patterson, Paul

    2007-01-01

    A proposed valve for controlling the rate of flow of a fluid would include an electric-motor-driven ball-screw mechanism for adjusting the seating element of the valve to any position between fully closed and fully open. The motor would be of a type that can be electronically controlled to rotate to a specified angular position and to rotate at a specified rate, and the ball screw would enable accurate linear positioning of the seating element as a function of angular position of the motor. Hence, the proposed valve would enable fine electronic control of the rate of flow and the rate of change of flow. The uniqueness of this valve lies in a high degree of integration of the actuation mechanism with the flow-control components into a single, relatively compact unit. A notable feature of this integration is that in addition to being a major part of the actuation mechanism, the ball screw would also be a flow-control component: the ball screw would be hollow so as to contain part of the main flow passage, and one end of the ball screw would be the main seating valve element. The relationships among the components of the valve are best understood by reference to the figure, which presents meridional cross sections of the valve in the fully closed and fully open positions. The motor would be supported by a bracket bolted to the valve body. By means of gears or pulleys and a timing belt, motor drive would be transmitted to a sleeve that would rotate on bearings in the valve body. A ball nut inside the sleeve would be made to rotate with the sleeve by use of a key. The ball screw would pass through and engage the ball nut. A key would prevent rotation of the ball screw in the valve body while allowing the ball screw to translate axially when driven by the ball nut. The outer surface of the ball screw would be threaded only in a mid-length region: the end regions of the outer surface of the ball screw would be polished so that they could act as dynamic sealing surfaces

  9. Dry Flowing Abrasive Decontamination Technique for Pipe Systems with Swirling Air Flow

    SciTech Connect

    Kameo, Yutaka; Nakashima, Mikio; Hirabayashi, Takakuni

    2003-10-15

    A dry abrasive decontamination method was developed for removing radioactive corrosion products from surfaces of coolant pipe systems in decommissioning of a nuclear power plant. Erosion behavior of inside surfaces of stainless and carbon steel pipes by a swirling air flow containing alumina or cast-iron grit abrasive was studied. Erosion depths of the test pipes were approximately proportional to an abrasive concentration in air and an exponent of flow rate of airstream. The experimental results indicated that the present method could keep satisfactory erosion ability of abrasives even for a large-size pipe. The present method was successfully applied to {sup 60}Co-contaminated specimens sampled from a pipe of the water cleanup system of the Japan Power Demonstration Reactor.

  10. Integrated turbine-compressor provides air flow for cooling

    NASA Technical Reports Server (NTRS)

    Ferri, A.

    1970-01-01

    Modified supersonic turbine cycle provides cooling air to surrounding structures. Simplified mechanical design assures correct balance of air flow, allows direct issue of cool air to the structure, and assists in matching turbine work output to work input required by the compressor.

  11. Research on Air Flow Measurement and Optimization of Control Algorithm in Air Disinfection System

    NASA Astrophysics Data System (ADS)

    Bing-jie, Li; Jia-hong, Zhao; Xu, Wang; Amuer, Mohamode; Zhi-liang, Wang

    2013-01-01

    As the air flow control system has the characteristics of delay and uncertainty, this research designed and achieved a practical air flow control system by using the hydrodynamic theory and the modern control theory. Firstly, the mathematical model of the air flow distribution of the system is analyzed from the hydrodynamics perspective. Then the model of the system is transformed into a lumped parameter state space expression by using the Galerkin method. Finally, the air flow is distributed more evenly through the estimation of the system state and optimal control. The simulation results show that this algorithm has good robustness and anti-interference ability

  12. Two-phase air-water stratified flow measurement using ultrasonic techniques

    SciTech Connect

    Fan, Shiwei; Yan, Tinghu; Yeung, Hoi

    2014-04-11

    In this paper, a time resolved ultrasound system was developed for investigating two-phase air-water stratified flow. The hardware of the system includes a pulsed wave transducer, a pulser/receiver, and a digital oscilloscope. The time domain cross correlation method is used to calculate the velocity profile along ultrasonic beam. The system is able to provide velocities with spatial resolution of around 1mm and the temporal resolution of 200μs. Experiments were carried out on single phase water flow and two-phase air-water stratified flow. For single phase water flow, the flow rates from ultrasound system were compared with those from electromagnetic flow (EM) meter, which showed good agreement. Then, the experiments were conducted on two-phase air-water stratified flow and the results were given. Compared with liquid height measurement from conductance probe, it indicated that the measured velocities were explainable.

  13. Three-dimensional freezing of flowing water in a tube cooled by air flow

    NASA Astrophysics Data System (ADS)

    Sugawara, M.; Komatsu, Y.; Beer, H.

    2015-05-01

    The 3-D freezing of flowing water in a copper tube cooled by air flow is investigated by means of a numerical analysis. The air flows normal to the tube axis. Several parameters as inlet water mean velocity w m , inlet water temperature T iℓ t , air flow temperature T a and air flow velocity u a are selected in the calculations to adapt it to a winter season actually encountered. The numerical results present the development of the ice layer mean thickness and its 3-D morphologies as well as the critical ice layer thickness in the tube choked by the ice layer.

  14. Laser sheet light flow visualization for evaluating room air flowsfrom Registers

    SciTech Connect

    Walker, Iain S.; Claret, Valerie; Smith, Brian

    2006-04-01

    Forced air heating and cooling systems and whole house ventilation systems deliver air to individual rooms in a house via supply registers located on walls ceilings or floors; and occasionally less straightforward locations like toe-kicks below cabinets. Ideally, the air velocity out of the registers combined with the turbulence of the flow, vectoring of air by register vanes and geometry of register placement combine to mix the supply air within the room. A particular issue that has been raised recently is the performance of multiple capacity and air flow HVAC systems. These systems vary the air flow rate through the distribution system depending on the system load, or if operating in a ventilation rather than a space conditioning mode. These systems have been developed to maximize equipment efficiency, however, the high efficiency ratings do not include any room mixing effects. At lower air flow rates, there is the possibility that room air will be poorly mixed, leading to thermal stratification and reduced comfort for occupants. This can lead to increased energy use as the occupants adjust the thermostat settings to compensate and parts of the conditioned space have higher envelope temperature differences than for the well mixed case. In addition, lack of comfort can be a barrier to market acceptance of these higher efficiency systems To investigate the effect on room mixing of reduced air flow rates requires the measurement of mixing of supply air with room air throughout the space to be conditioned. This is a particularly difficult exercise if we want to determine the transient performance of the space conditioning system. Full scale experiments can be done in special test chambers, but the spatial resolution required to fully examine the mixing problem is usually limited by the sheer number of thermal sensors required. Current full-scale laboratory testing is therefore severely limited in its resolution. As an alternative, we used a water-filled scale model

  15. Surface-slip equations for multicomponent nonequilibrium air flow

    NASA Technical Reports Server (NTRS)

    Gupta, R. N.; Scott, C. D.; Moss, J. N.

    1985-01-01

    Equations are presented for the surface-slip (or jump) values of species concentration, pressure, velocity, and temperature in the low-Reynolds number, high-altitude flight regime of a space vehicle. The equations are obtained from closed form solutions of the mass, momentum, and energy flux equations using the Chapman-Enskog velocity distribution function. This function represents a solution of the Boltzmann equation in the Navier-Stokes approximation. The analysis, obtained for nonequilibrium multicomponent air flow, includes the finite-rate surface catalytic recombination and changes in the internal energy during reflection from the surface. Expressions for the various slip quantities were obtained in a form which can be employed in flowfield computations. A consistent set of equations is provided for multicomponent, binary, and single species mixtures. Expression is also provided for the finite-rate, species-concentration boundary condition for a multicomponent mixture in absence of slip.

  16. Deconvolution of wellbore pressure and flow rate

    SciTech Connect

    Kuchuk, F.J. ); Carter, R.G. . Langley Research Center); Ayestaran, L. )

    1990-03-01

    Determination of the influence function of a well/reservoir system from the deconvolution of wellbore flow rate and pressure is presented. Deconvolution is fundamental and is particularly applicable to system identification. A variety of different deconvolution algorithms are presented. The simplest algorithm is a direct method that works well for data without measurement noise but that fails in the presence of even small amounts of noise. The authors show, however, that a modified algorithm that imposes constraints on the solution set works well, even with significant measurement errors.

  17. Solids flow rate measurement in dense slurries

    SciTech Connect

    Porges, K.G.; Doss, E.D.

    1993-09-01

    Accurate and rapid flow rate measurement of solids in dense slurries remains an unsolved technical problem, with important industrial applications in chemical processing plants and long-distance solids conveyance. In a hostile two-phase medium, such a measurement calls for two independent parameter determinations, both by non-intrusive means. Typically, dense slurries tend to flow in laminar, non-Newtonian mode, eliminating most conventional means that usually rely on calibration (which becomes more difficult and costly for high pressure and temperature media). These issues are reviewed, and specific solutions are recommended in this report. Detailed calculations that lead to improved measuring device designs are presented for both bulk density and average velocity measurements. Cross-correlation, chosen here for the latter task, has long been too inaccurate for practical applications. The cause and the cure of this deficiency are discussed using theory-supported modeling. Fluid Mechanics are used to develop the velocity profiles of laminar non-Newtonian flow in a rectangular duct. This geometry uniquely allows the design of highly accurate `capacitive` devices and also lends itself to gamma transmission densitometry on an absolute basis. An absolute readout, though of less accuracy, is also available from a capacitive densitometer and a pair of capacitive sensors yields signals suitable for cross-correlation velocity measurement.

  18. Influence of the Flow Rate of Oxidising Atmosphere on the Flame Spread Rate on the Surface of Organic Setlled Dust

    NASA Astrophysics Data System (ADS)

    Martinka, Jozef; Balog, Karol; Hrušovský, Ivan; Valentová, Veronika

    2013-01-01

    The presented paper deals with determining the influence of the flow rate of oxidising atmosphere on the flame spread along the surface of the organic settled dust layer. We determined the rate of the flame spread on the surface of the organic settled dust layer (whole grain rye and spelt flour) with absolute moisture of 10 % wt., for the flow rates of oxidising atmosphere 1, 3, 5 and 10 cm/s. Pure oxygen was used as an oxidising atmosphere. The obtained results suggest that there exists a power relationship of the flame spread rate along the surface of organic settled dust layer to the flow rate of the oxidising mixture. The method described is suitable for the relative comparison of the organic settled dust layer from the point of its ability to spread the flame and the influence of the air flow rate on this process.

  19. Relief, nocturnal cold-air flow and air quality in Kigali, Rwanda

    NASA Astrophysics Data System (ADS)

    Henninger, Sascha

    2013-04-01

    , this result is not reassuringly, because all measured residential districts in Kigali exceeded the recommendations of the WHO, too. This suggests that the inhabitants of Kigali are exposed to enormous levels of PM10 during most of their time outdoors. So PM10 levels are increasing in areas with high rates of traffic due to the exhaust of the vehicles and the stirring up of dust from the ground, but also in fact of burning wood for cooking etc. within the residential districts. Hazardous measuring trips could be detected for nighttime measurements. Because of high temperatures, high solar radiation and a non-typical missing cloud cover the urban surface could heat up extremely, which produced a cold-air flow from the ridges and the slopes down to the "Marais" at night. This cold-air flow takes away the suspended particulate matters, which tends to accumulate within the "Marais" on the bottom of the hills, the places where most residential neighborhoods could be found and agricultural fields were used. The distinctive relief caused an accumulation within small valleys. Unfortunately, these are the favourite places of living and agriculture and this tends to high indoor-air pollution.

  20. Adjustable flow rate controller for polymer solutions

    DOEpatents

    Jackson, Kenneth M.

    1981-01-01

    An adjustable device for controlling the flow rate of polymer solutions which results in only little shearing of the polymer molecules, said device comprising an inlet manifold, an outlet manifold, a plurality of tubes capable of providing communication between said inlet and outlet manifolds, said tubes each having an internal diameter that is smaller than that of the inlet manifold and large enough to insure that viscosity of the polymer solution passing through each said tube will not be reduced more than about 25 percent, and a valve associated with each tube, said valve being capable of opening or closing communication in that tube between the inlet and outlet manifolds, each said valve when fully open having a diameter that is substantially at least as great as that of the tube with which it is associated.

  1. Quantitative Estimation of Tissue Blood Flow Rate.

    PubMed

    Tozer, Gillian M; Prise, Vivien E; Cunningham, Vincent J

    2016-01-01

    The rate of blood flow through a tissue (F) is a critical parameter for assessing the functional efficiency of a blood vessel network following angiogenesis. This chapter aims to provide the principles behind the estimation of F, how F relates to other commonly used measures of tissue perfusion, and a practical approach for estimating F in laboratory animals, using small readily diffusible and metabolically inert radio-tracers. The methods described require relatively nonspecialized equipment. However, the analytical descriptions apply equally to complementary techniques involving more sophisticated noninvasive imaging.Two techniques are described for the quantitative estimation of F based on measuring the rate of tissue uptake following intravenous administration of radioactive iodo-antipyrine (or other suitable tracer). The Tissue Equilibration Technique is the classical approach and the Indicator Fractionation Technique, which is simpler to perform, is a practical alternative in many cases. The experimental procedures and analytical methods for both techniques are given, as well as guidelines for choosing the most appropriate method. PMID:27172960

  2. 14 CFR 23.1095 - Carburetor deicing fluid flow rate.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor deicing fluid flow rate. 23.1095... Induction System § 23.1095 Carburetor deicing fluid flow rate. (a) If a carburetor deicing fluid system is used, it must be able to simultaneously supply each engine with a rate of fluid flow, expressed...

  3. 14 CFR 23.1095 - Carburetor deicing fluid flow rate.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor deicing fluid flow rate. 23.1095... Induction System § 23.1095 Carburetor deicing fluid flow rate. (a) If a carburetor deicing fluid system is used, it must be able to simultaneously supply each engine with a rate of fluid flow, expressed...

  4. 14 CFR 23.1095 - Carburetor deicing fluid flow rate.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor deicing fluid flow rate. 23.1095... Induction System § 23.1095 Carburetor deicing fluid flow rate. (a) If a carburetor deicing fluid system is used, it must be able to simultaneously supply each engine with a rate of fluid flow, expressed...

  5. 14 CFR 23.1095 - Carburetor deicing fluid flow rate.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor deicing fluid flow rate. 23.1095... Induction System § 23.1095 Carburetor deicing fluid flow rate. (a) If a carburetor deicing fluid system is used, it must be able to simultaneously supply each engine with a rate of fluid flow, expressed...

  6. 14 CFR 23.1095 - Carburetor deicing fluid flow rate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor deicing fluid flow rate. 23.1095... Induction System § 23.1095 Carburetor deicing fluid flow rate. (a) If a carburetor deicing fluid system is used, it must be able to simultaneously supply each engine with a rate of fluid flow, expressed...

  7. 46 CFR 162.018-7 - Flow rating tests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Flow rating tests. 162.018-7 Section 162.018-7 Shipping...: SPECIFICATIONS AND APPROVAL ENGINEERING EQUIPMENT Safety Relief Valves, Liquefied Compressed Gas § 162.018-7 Flow rating tests. (a) Flow rating of valves shall be conducted in accordance with UG-131 of section VIII...

  8. Computational modeling of air-breathing microfluidic fuel cells with flow-over and flow-through anodes

    NASA Astrophysics Data System (ADS)

    Zhang, Biao; Ye, Ding-ding; Sui, Pang-Chieh; Djilali, Ned; Zhu, Xun

    2014-08-01

    A three-dimensional computational model for air-breathing microfluidic fuel cells (AMFCs) with flow-over and flow-through anodes is developed. The coupled multiphysics phenomena of fluid flow, species transport and electrochemical reactions are resolved numerically. The model has been validated against experimental data using an in-house AMFC prototype with a flow-through anode. Characteristics of fuel transfer and fuel crossover for both types of anodes are investigated. The model results reveal that the fuel transport to the flow-over anode is intrinsically limited by the fuel concentration boundary layer. Conversely, fuel transport for the flow-through anode is convectively enhanced by the permeate flow, and no concentration boundary layer is observed. An unexpected additional advantage of the flow-through anode configuration is lower parasitic (crossover) current density than the flow-over case at practical low flow rates. Cell performance of the flow-through case is found to be limited by reaction kinetics. The present model provides insights into the fuel transport and fuel crossover in air-breathing microfluidic fuel cells and provides guidance for further design and operation optimization.

  9. Supersonic Air Flow due to Solid-Liquid Impact

    NASA Astrophysics Data System (ADS)

    Gekle, Stephan; Peters, Ivo R.; Gordillo, José Manuel; van der Meer, Devaraj; Lohse, Detlef

    2010-01-01

    A solid object impacting on liquid creates a liquid jet due to the collapse of the impact cavity. Using visualization experiments with smoke particles and multiscale simulations, we show that in addition, a high-speed air jet is pushed out of the cavity. Despite an impact velocity of only 1m/s, this air jet attains supersonic speeds already when the cavity is slightly larger than 1 mm in diameter. The structure of the air flow closely resembles that of compressible flow through a nozzle—with the key difference that here the “nozzle” is a liquid cavity shrinking rapidly in time.

  10. Computational and experimental study of spin coater air flow

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaoguang; Liang, Faqiu; Haji-Sheikh, A.; Ghariban, N.

    1998-06-01

    An extensive 2- and 3-D analysis of air flow in a POLARISTM 2200 Microlithography Cluster spin coater was conducted using FLUENTTM Computational Fluid Dynamics (CFD) software. To supplement this analysis, direct measurement of air flow velocity was also performed using a DantecTM Hot Wire Anemometer. Velocity measurements were made along two major planes across the entire flow field in the spin coater at various operating conditions. It was found that the flow velocity at the spin coater inlet is much lower than previously assumed and quite nonuniform. Based on this observation, a pressure boundary condition rather than a velocity boundary condition was used for subsequent CFD analysis. A comparison between calculated results and experimental data shows that the 3D model accurately predicts the air flow field in the spin coater. An added advantage of this approach is that the CFD model can be easily generated from the mechanical design database and used to analyze the effect of design changes. The modeled and measured results show that the flow pattern in the spin bowl is affected by interactions between the spinning wafer, exhaust flow, and the gap between the spin head and surrounding baffle. Different operating conditions such as spin speed, inlet pressure, and exhaust pressure were found to generate substantially different flow patterns. It was also found that backflow of air could be generated under certain conditions.

  11. Low-noise flow valve for air ducts

    NASA Technical Reports Server (NTRS)

    Gallo, E. A.

    1970-01-01

    Valve assembly controls air flow from feeder into main duct, with minimum of turbulence, friction, pressure differential, and noise. Valve consists of damper, deflector, and spring. Streamlining of damper and deflector merges flow smoothly, while spring keeps damper and deflector in contact and eliminates valve chatter and damping vibrations.

  12. Measuring the rate of local evaporation from the liquid surface under the action of gas flow

    NASA Astrophysics Data System (ADS)

    Lyulin, Yu. V.; Feoktistov, D. V.; Afanas'ev, I. A.; Chachilo, E. S.; Kabov, O. A.; Kuznetsov, G. V.

    2015-07-01

    The dynamics of evaporation from the surface of a liquid layer under the action of a gas flow has been studied. Correlation dependences of the rate of liquid evaporation on the gas flow rate and temperature for the ethanol-air system have been obtained and compared to other published experimental data. It is established that, for the two-phase systems studied, the evaporation rate growth with increasing temperature exhibits an almost identical character independently of the thermal properties of particular liquids and gases. In contrast, the character of the evaporation rate growth with increasing gas flow velocity significantly depends on these properties.

  13. Low power, constant-flow air pump systems

    SciTech Connect

    Polito, M.D.; Albert, B.

    1994-01-01

    A rugged, yet small and lightweight constant-flow air pump system has been designed. Flow control is achieved using a novel approach which is three times more power efficient than previous designs. The resultant savings in battery size and weight makes these pumps ideal for sampling air on balloon platforms. The pump package includes meteorological sensors and an onboard computer that stores time and sensor data and turns the constant-flow pump circuit on/off. Some applications of these systems are also presented in this report.

  14. Visualization of the air flow behind the automotive benchmark vent

    NASA Astrophysics Data System (ADS)

    Pech, Ondrej; Jedelsky, Jan; Caletka, Petr; Jicha, Miroslav

    2015-05-01

    Passenger comfort in cars depends on appropriate function of the cabin HVAC system. A great attention is therefore paid to the effective function of automotive vents and proper formation of the flow behind the ventilation outlet. The article deals with the visualization of air flow from the automotive benchmark vent. The visualization was made for two different shapes of the inlet channel connected to the benchmark vent. The smoke visualization with the laser knife was used. The influence of the shape of the inlet channel to the airflow direction, its enlargement and position of air flow axis were investigated.

  15. Greenhouse Gas Growth Rates from AIRS Hyperspectral Radiance Time Series

    NASA Astrophysics Data System (ADS)

    Strow, L. L.; Desouza-Machado, S. G.; Hannon, S.; Imbiriba, B.; Schou, P.

    2009-12-01

    The AIRS seven year hyperspectral radiance record provides an ideal platform for measurings growth rates of infrared active minor gases, especially carbon dioxide and methane. The largest changes in CLARREO radiances will likely be due to increasing carbon dioxide and other greenhouse gases. We have produced a 5+ year record of almost cloud-free AIRS radiances, from which we have derived the radiance anomaly and linear time rate of change. The source of these radiances are the L1b radiances corrected for small frequency drifts. Growth rates of carbon dioxide, nitrous oxide, methane, ozone, and CFC11 are simultaneously derived from zonal averages of these radiance rates for tropics, and mid-latitude northern and southern hemispheres. The effective linear rate of change of ~5 layers of water vapor and temperature, plus the surface temperature are also simultaneously derived with the minor gas rates. No model data or prior is needed and more than 1000 channels are used in the fit. Sampling issues may preclude the use of the mid-latitude temperature and water vapor rates for climate analysis, but possibly not for the tropics. The resulting greenhouse gas growth rates agree very well with in-situ measurements, which suggests high radiometric stability for AIRS. Radiance intercomparisons for climate analysis between IASI and AIRS will also be presented.

  16. Relationship between air exchange rate and indoor VOC levels

    SciTech Connect

    Otson, R.; Williams, D.T.; Fellin, P.

    1998-12-31

    It is often assumed that the air quality is better in leaky than in airtight buildings. To test this anecdotal hypothesis, data from two Canadian surveys were examined. Indoor measurements of 28 volatile organic compounds (VOCs) were made by means of a passive sampling method during the 24 to 48 h study periods in both studies, and air exchange rates were determined by the perfluorocarbon tracer approach. The air exchange rates ranged between about 0.1 to 2.5 air changes per hour in 54 test homes in the Greater Toronto Area (GTA). Other information on building age and construction, renovation activities and occupant activities that potentially influenced indoor VOC concentrations in the homes was collected by means of a questionnaire. The statistical relationships between the concentrations of VOCs and air exchange were determined. Correlation coefficients between the airborne concentrations of each VOC and the air exchange rates for the homes were all < 0.1 indicating that the relationship between the air exchange and indoor VOC concentrations is tenuous. Since the questionnaire responses did not provide quantitative estimates of indoor emissions, a quantitative correlation between responses and indoor concentrations could not be established nor was a consistent pattern evident between these responses and the occurrence of high indoor concentrations. The lack of definitive quantitative relationships is not surprising considering the complexity of indoor environments, the lack of a detailed inventory of indoor sources and their emission rates and a lack of information or understanding of indoor sinks. The findings, on the effect of air exchange rates and the value of questionnaires in studies on indoor VOCs are consistent with findings in other similar studies.

  17. the nature of air flow near the inlets of blunt dust sampling probes

    NASA Astrophysics Data System (ADS)

    Vincent, J. H.; Hutson, D.; Mark, D.

    This paper sets out to describe the nature of air flow near blunt dust samplers in a way which allows a relatively simple assessment of their performances for collecting dust particles. Of particular importance is the shape of the limiting stream surface which divides the sampled air from that which passes outside the sampler, and how this is affected by the free-stream air velocity, the sampling flow rate, and the shape of the sampler body. This was investigated for two-dimensional and axially-symmetric sampler systems by means of complementary experiments using electrolytic tank potential flow analogues and a wind tunnel respectively. For extreme conditions the flow of air entering the sampling orifice may be wholly divergent or wholly convergent. For a wide range of intermediate conditions, however, the flow first diverges then converges, exhibiting a so-called "spring onion effect". Whichever of these applies for a particular situation, the flow may be considered to consist of two parts, the outer one dominated by the flow about the sampler body and the inner one dominated by the flow into the sampling orifice. Particle transport in this two-part flow may be assessed using ideas borrowed from thin-walled probe theory.

  18. Annular fuel and air co-flow premixer

    SciTech Connect

    Stevenson, Christian Xavier; Melton, Patrick Benedict; York, William David

    2013-10-15

    Disclosed is a premixer for a combustor including an annular outer shell and an annular inner shell. The inner shell defines an inner flow channel inside of the inner shell and is located to define an outer flow channel between the outer shell and the inner shell. A fuel discharge annulus is located between the outer flow channel and the inner flow channel and is configured to inject a fuel flow into a mixing area in a direction substantially parallel to an outer airflow through the outer flow channel and an inner flow through the inner flow channel. Further disclosed are a combustor including a plurality of premixers and a method of premixing air and fuel in a combustor.

  19. Residential air exchange rates for use in indoor air and exposure modeling studies.

    PubMed

    Pandian, M D; Ott, W R; Behar, J V

    1993-01-01

    Data on air exchange rates are important inputs to indoor air quality models. Indoor air models, in turn, are incorporated into the structure of total human exposure models. Fragmentary data on residential ventilation rates are available in various governmental reports, journal articles, and contractor reports. Most of the published papers present data on only a few homes to answer very specialized questions, and none of these publications summarize the ventilation rates of a large population of homes across the United States. Brookhaven National Laboratory (BNL) has conducted more than 4000 residential perfluorocarbon tracer (PFT) measurements and brought them together into a large data base from about 100 studies in the United States and elsewhere. This paper analyzes the BNL PFT data base to generate frequency distributions and summary statistics for different regions of the United States, different seasons, and different levels within the homes. The data analyses suggest that residential ventilation rates are similar in the northeastern and northwestern states but higher in the southwestern states. Winter and fall ventilation rates are similar, but the rates are slightly higher in spring, and much higher in summer. Multi-level residences have higher air exchange rates than single-level residences. Although the BNL data are not a representative sample of homes in the United States, these analyses give insight into the range of air exchange rates found in the United States under a great variety of conditions and are intended for use by developers of models of indoor air quality and total human exposure. PMID:8173341

  20. A criterion for the onset of slugging in horizontal stratified air-water countercurrent flow

    SciTech Connect

    Chun, Moon-Hyun; Lee, Byung-Ryung; Kim, Yang-Seok

    1995-09-01

    This paper presents an experimental and theoretical investigation of wave height and transition criterion from wavy to slug flow in horizontal air-water countercurrent stratified flow conditions. A theoretical formula for the wave height in a stratified wavy flow regime has been developed using the concept of total energy balance over a wave crest to consider the shear stress acting on the interface of two fluids. From the limiting condition of the formula for the wave height, a necessary criterion for transition from a stratified wavy flow to a slug flow has been derived. A series of experiments have been conducted changing the non-dimensional water depth and the flow rates of air in a horizontal pipe and a duct. Comparisons between the measured data and the predictions of the present theory show that the agreement is within {plus_minus}8%.

  1. Spool Valve for Switching Air Flows Between Two Beds

    NASA Technical Reports Server (NTRS)

    Dean, W. Clark

    2005-01-01

    U.S. Patent 6,142,151 describes a dual-bed ventilation system for a space suit, with emphasis on a multiport spool valve that switches air flows between two chemical beds that adsorb carbon dioxide and water vapor. The valve is used to alternately make the air flow through one bed while exposing the other bed to the outer-space environment to regenerate that bed through vacuum desorption of CO2 and H2O. Oxygen flowing from a supply tank is routed through a pair of periodically switched solenoid valves to drive the spool valve in a reciprocating motion. The spool valve equalizes the pressures of air in the beds and the volumes of air flowing into and out of the beds during the alternations between the adsorption and desorption phases, in such a manner that the volume of air that must be vented to outer space is half of what it would be in the absence of pressure equalization. Oxygen that has been used to actuate the spool valve in its reciprocating motion is released into the ventilation loop to replenish air lost to vacuum during the previous desorption phase of the operating cycle.

  2. Equipment for Measuring Air Flow, Air Temperature, Relative Humidity, and Carbon Dioxide in Schools. Technical Bulletin.

    ERIC Educational Resources Information Center

    Jacobs, Bruce W.

    Information on equipment and techniques that school facility personnel may use to evaluate IAQ conditions are discussed. Focus is placed on the IAQ parameters of air flow, air temperature, relative humidity, as well as carbon dioxide and the equipment used to measure these factors. Reasons for measurement and for when the measurement of these…

  3. Technique for measuring air flow and carbon dioxide flux in large, open-top chambers

    SciTech Connect

    Ham, J.M.; Owensby, C.E.; Coyne, P.I.

    1993-10-01

    Open-Top Chambers (OTCs) are commonly used to evaluate the effect of CO{sub 2},O{sub 3}, and other trace gases on vegetation. This study developed and tested a new technique for measuring forced air flow and net CO{sub 2} flux from OTCs. Experiments were performed with a 4.5-m diam. OTC with a sealed floor and a specialized air delivery system. Air flow through the chamber was computed with the Bernoulli equation using measurements of the pressure differential between the air delivery ducts and the chamber interior. An independent measurement of air flow was made simultaneously to calibrate and verify the accuracy of the Bernoulli relationship. The CO{sub 2} flux density was calculated as the product of chamber air flow and the difference in CO{sub 2} concentration between the air entering and exhausting from the OTC (C{sub in}-C{sub out}). Accuracy was evaluated by releasing CO{sub 2} within the OTC at known rates. Data were collected with OTCs at ambient and elevated CO{sub 2} ({approx}700 {mu}mol{sup -1}). Results showed the Bernoulli equation, with a flow coefficient of 0.7, accurately measured air flow in the OTC within {+-}5% regardless of flow rate and air duct geometry. Experiments in ambient OTCs showed CO{sub 2} flux density ({mu}mol m{sup -2} s{sup -1}), computed from 2-min averages of air flow and C{sub in} - C{sub out,} was typically within {+-} 10% of actual flux, provided that the exit air velocity at the top of the OTC was greater than 0.6 m s{sup -1}. Obtaining the same accuracy in CO{sub 2}-enriched OTCs required a critical exit velocity near 1.2 m s{sup -1} to minimize the incursion of ambient air and prevent contamination of exit gas sample. When flux data were integrated over time to estimate daily CO{sub 2} flux ({mu}mol m{sup -2} d{sup -1}), actual and measured values agreed to within {+-}2% for both ambient and CO{sub 2}-enriched chambers, suggesting that accurate measurements of daily net C exchange are possible with this technique.

  4. Development of a Low Pressure, Air Atomized Oil Burner with High Atomizer Air Flow: Progress Report FY 1997

    SciTech Connect

    Butcher, T.A.

    1998-01-01

    This report describes technical advances made to the concept of a low pressure, air atomized oil burner for home heating applications. Currently all oil burners on the market are of the pressure atomized, retention head type. These burners have a lower firing rate limit of about 0.5 gallons per hour of oil, due to reliability problems related to small flow passage sizes. High pressure air atomized burners have been shown to be one route to avoid this problem but air compressor cost and reliability have practically eliminated this approach. With the low pressure air atomized burner the air required for atomization can be provided by a fan at 5-8 inches of water pressure. A burner using this concept, termed the Fan-Atomized Burner or ''FAB'' has been developed and is currently being commercialized. In the head of the FAB, the combustion air is divided into three parts, much like a conventional retention head burner. This report describes development work on a new concept in which 100% of the air from the fan goes through the atomizer. The primary advantage of this approach is a great simplification of the head design. A nozzle specifically sized for this concept was built and is described in the report. Basic flow pressure tests, cold air velocity profiles, and atomization performance have been measured. A burner head/flame tube has been developed which promotes a toroidal recirculation zone near the nozzle for flame stability. The burner head has been tested in several furnace and boiler applications over the firing rate range 0.2 to 0.28 gallons per hour. In all cases the burner can operate with very low excess air levels (under 10%) without producing smoke. Flue gas NO{sub x} concentration varied from 42 to 62 ppm at 3% O{sub 2}. The concept is seen as having significant potential and planned development efforts are discussed.

  5. Natural laminar flow hits smoother air

    NASA Technical Reports Server (NTRS)

    Holmes, B. J.

    1985-01-01

    Natural laminar flow (NLF) may be attained in aircraft with lower cost, weight, and maintenance penalties than active flow laminarization by means of a slot suction system. A high performance general aviation jet aircraft possessing a moderate degree of NLF over wing, fuselage, empennage and engine nacelles will accrue a 24 percent reduction in total aircraft drag in the cruise regime. NASA-Langley has conducted NLF research centered on the use of novel airfoil profiles as well as composite and milled aluminum alloy construction methods which minimize three-dimensional aerodynamic surface roughness and waviness. It is noted that higher flight altitudes intrinsically reduce unit Reynolds numbers, thereby minimizing turbulence for a given cruise speed.

  6. Nutrient transport as affected by rate of overland flow

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little information is currently available concerning the effects of varying flow rate on nutrient transport by overland flow. The objective of this study was to measure the effects of overland flow rate on nutrient transport following the application of beef cattle or swine manure to plots containin...

  7. Optical Air Flow Measurements in Flight

    NASA Technical Reports Server (NTRS)

    Bogue, Rodney K.; Jentink, Henk W.

    2004-01-01

    This document has been written to assist the flight-test engineer and researcher in using optical flow measurements in flight applications. The emphasis is on describing tradeoffs in system design to provide desired measurement performance as currently understood. Optical system components are discussed with examples that illustrate the issues. The document concludes with descriptions of optical measurement systems designed for a variety of applications including aeronautics research, airspeed measurement, and turbulence hazard detection. Theoretical discussion is minimized, but numerous references are provided to supply ample opportunity for the reader to understand the theoretical underpinning of optical concepts.

  8. An experimental study of geyser-like flows induced by a pressurized air pocket

    NASA Astrophysics Data System (ADS)

    Elayeb, I. S.; Leon, A.; Choi, Y.; Alnahit, A. O.

    2015-12-01

    Previous studies argues that the entrapment of pressurized air pockets within combined sewer systems can produce geyser flows, which is an oscillating jetting of a mixture of gas-liquid flows. To verify that pressurized air pockets can effectively produce geysers, laboratory experiments were conducted. However, past experiments were conducted in relatively small-scale apparatus (i.e. maximum φ2" vertical shaft). This study conducted a set of experiments in a larger apparatus. The experimental setup consists of an upstream head tank, a downstream head tank, a horizontal pipe (46.5ft long, φ6") and a vertical pipe (10ft long, φ6"). The initial condition for the experiments is constant flow discharge through the horizontal pipe. The experiments are initiated by injecting an air pocket with pre-determined volume and pressure at the upstream end of the horizontal pipe. The air pocket propagates through the horizontal pipe until it arrives to the vertical shaft, where it is released producing a geyser-like flow. Three flow rates in the horizontal pipe and three injected air pressures were tested. The variables measured were pressure at two locations in the horizontal pipe and two locations in the vertical pipe. High resolution videos at two regions in the vertical shaft were also recorded. To gain further insights in the physics of air-water interaction, the laboratory experiments were complemented with numerical simulations conducted using a commercial 3D CFD model, previously validated with experiments.

  9. Device accurately measures and records low gas-flow rates

    NASA Technical Reports Server (NTRS)

    Branum, L. W.

    1966-01-01

    Free-floating piston in a vertical column accurately measures and records low gas-flow rates. The system may be calibrated, using an adjustable flow-rate gas supply, a low pressure gage, and a sequence recorder. From the calibration rates, a nomograph may be made for easy reduction. Temperature correction may be added for further accuracy.

  10. Ionospheric Heating Rates Associated with Solar Wind Forcing: Ejecta flow, High Speed Flow and Slow Flow

    NASA Astrophysics Data System (ADS)

    Knipp, D. J.; Kasprzak, B.; Richardson, I.; Paige, T.; Evans, D.

    2001-12-01

    We present estimates of global ionospheric Joule and particle heating as a function of solar wind flow types over solar cycles 21, 22 and the first half of solar cycle 23. Richardson et al., [JGR, 2000] used a variety of techniques to categorize the solar wind flow as ejecta, high-speed stream or slow flow. Their work provides the basis for our catigorization of heating by flow type. The estimates of Joule heating are based on output of the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure, and fits to the Polar Cap Index [Chun et al., GRL, 1999]. Estimates of particle heating are derived from polar orbiting satellites. Although ejecta only account for 19% of the solar wind flow, they account for 27% of the Joule heating. High-speed stream flow accounts for 47% of the flow occurrence and 44% of the Joule heating. We will show similar comparisons for particle heating. Our solar cycle statistics indicate that Joule heating produces a yearly average hemispheric heating rate of 53 GW while particles produce a hemispheric heating rate of 38 GW. Joule heating exhibits more variability than particle heating. During solar cycle maximum years Joule heating accounts for twice the heating associated with particles heating.

  11. Air flow management in an internal combustion engine through the use of electronically controlled air jets

    SciTech Connect

    Swain, M.R.

    1988-12-27

    This patent describes a means for producing an air/fuel mixture in the valve pocket and means for directing the air/fuel mixture past the intake valve into the combustion chamber, the improvement comprising a device for generating a swirling flow of the air/fuel mixture in the combustion chamber to thereby obtain greater combustion stability. The device has a nozzle positioned within the valve pocket and directed at an acute angle toward the intake valve comprising at least one opening for receiving air, connected to a first pathway, and at least one opening for expelling air, connected, to a second pathway joined to the first pathway and extending to the expulsion opening. The device also includes a means for controlling the flow of air through the pathway and out the expulsion opening comprising: (i) a stopper having sides complementary in shape to the pair of opposed arcuate walls movable from an open position allowing air through the pathway to a closed position, wherein the sides of the stopper are in a sealed relationship with the opposed arcaute sides of the junction thereby preventing the flow of air through the second pathway and out of the expulsion opening; and (ii) an electronic computer which determines the size and duration of the pathway opening.

  12. Thin-Film Air-Mass-Flow Sensor of Improved Design Developed

    NASA Technical Reports Server (NTRS)

    Fralick, Gustave C.; Wrbanek, John D.; Hwang, Danny P.

    2003-01-01

    Researchers at the NASA Glenn Research Center have developed a new air-mass-flow sensor to solve the problems of existing mass flow sensor designs. NASA's design consists of thin-film resistors in a Wheatstone bridge arrangement. The resistors are fabricated on a thin, constant-thickness airfoil to minimize disturbance to the airflow being measured. The following photograph shows one of NASA s prototype sensors. In comparison to other air-mass-flow sensor designs, NASA s thin-film sensor is much more robust than hot wires, causes less airflow disturbance than pitot tubes, is more accurate than vane anemometers, and is much simpler to operate than thermocouple rakes. NASA s thin-film air-mass-flow sensor works by converting the temperature difference seen at each leg of the thin-film Wheatstone bridge into a mass-flow rate. The following figure shows a schematic of this sensor with air flowing around it. The sensor operates as follows: current is applied to the bridge, which increases its temperature. If there is no flow, all the arms are heated equally, the bridge remains in balance, and there is no signal. If there is flow, the air passing over the upstream legs of the bridge reduces the temperature of the upstream legs and that leads to reduced electrical resistance for those legs. After the air has picked up heat from the upstream legs, it continues and passes over the downstream legs of the bridge. The heated air raises the temperature of these legs, increasing their electrical resistance. The resistance difference between the upstream and downstream legs unbalances the bridge, causing a voltage difference that can be amplified and calibrated to the airflow rate. Separate sensors mounted on the airfoil measure the temperature of the airflow, which is used to complete the calculation for the mass of air passing by the sensor. A current application for air-mass-flow sensors is as part of the intake system for an internal combustion engine. A mass-flow sensor is

  13. Airway blood flow response to dry air hyperventilation in sheep

    SciTech Connect

    Parsons, G.H.; Baile, E.M.; Pare, P.D.

    1986-03-01

    Airway blood flow (Qaw) may be important in conditioning inspired air. To determine the effect of eucapneic dry air hyperventilation (hv) on Qaw in sheep the authors studied 7 anesthetized open-chest sheep after 25 min. of warm dry air hv. During each period of hv the authors have recorded vascular pressures, cardiac output (CO), and tracheal mucosal and inspired air temperature. Using a modification of the reference flow technique radiolabelled microspheres were injected into the left atrium to make separate measurements after humid air and dry air hv. In 4 animals a snare around the left main pulmonary artery was used following microsphere injection to prevent recirculation (entry into L lung of microspheres from the pulmonary artery). Qaw to the trachea and L lung as measured and Qaw for the R lung was estimated. After the final injection the sheep were killed and bronchi (Br) and lungs removed. Qaw (trachea plus L lung plus R lung) in 4 sheep increased from a mean of 30.8 to 67.0 ml/min. Airway mucosal temp. decreased from 39/sup 0/ to 33/sup 0/C. The authors conclude that dry air hv cools airway mucosa and increases Qaw in sheep.

  14. Laser filamentation induced air-flow motion in a diffusion cloud chamber.

    PubMed

    Sun, Haiyi; Liu, Jiansheng; Wang, Cheng; Ju, Jingjing; Wang, Zhanxin; Wang, Wentao; Ge, Xiaochun; Li, Chuang; Chin, See Leang; Li, Ruxin; Xu, Zhizhan

    2013-04-22

    We numerically simulated the air-flow motion in a diffusion cloud chamber induced by femtosecond laser filaments for different chopping rates. A two dimensional model was employed, where the laser filaments were treated as a heat flux source. The simulated patterns of flow fields and maximum velocity of updraft compare well with the experimental results for the chopping rates of 1, 5, 15 and 150 Hz. A quantitative inconsistency appears between simulated and experimental maximum velocity of updraft for 1 kHz repetition rate although a similar pattern of flow field is obtained, and the possible reasons were analyzed. Based on the present simulated results, the experimental observation of more water condensation/snow at higher chopping rate can be explained. These results indicate that the specific way of laser filament heating plays a significant role in the laser-induced motion of air flow, and at the same time, our previous conclusion of air flow having an important effect on water condensation/snow is confirmed. PMID:23609636

  15. An Open-Access Modeled Passenger Flow Matrix for the Global Air Network in 2010

    PubMed Central

    Huang, Zhuojie; Wu, Xiao; Garcia, Andres J.; Fik, Timothy J.; Tatem, Andrew J.

    2013-01-01

    The expanding global air network provides rapid and wide-reaching connections accelerating both domestic and international travel. To understand human movement patterns on the network and their socioeconomic, environmental and epidemiological implications, information on passenger flow is required. However, comprehensive data on global passenger flow remain difficult and expensive to obtain, prompting researchers to rely on scheduled flight seat capacity data or simple models of flow. This study describes the construction of an open-access modeled passenger flow matrix for all airports with a host city-population of more than 100,000 and within two transfers of air travel from various publicly available air travel datasets. Data on network characteristics, city population, and local area GDP amongst others are utilized as covariates in a spatial interaction framework to predict the air transportation flows between airports. Training datasets based on information from various transportation organizations in the United States, Canada and the European Union were assembled. A log-linear model controlling the random effects on origin, destination and the airport hierarchy was then built to predict passenger flows on the network, and compared to the results produced using previously published models. Validation analyses showed that the model presented here produced improved predictive power and accuracy compared to previously published models, yielding the highest successful prediction rate at the global scale. Based on this model, passenger flows between 1,491 airports on 644,406 unique routes were estimated in the prediction dataset. The airport node characteristics and estimated passenger flows are freely available as part of the Vector-Borne Disease Airline Importation Risk (VBD-Air) project at: www.vbd-air.com/data. PMID:23691194

  16. An open-access modeled passenger flow matrix for the global air network in 2010.

    PubMed

    Huang, Zhuojie; Wu, Xiao; Garcia, Andres J; Fik, Timothy J; Tatem, Andrew J

    2013-01-01

    The expanding global air network provides rapid and wide-reaching connections accelerating both domestic and international travel. To understand human movement patterns on the network and their socioeconomic, environmental and epidemiological implications, information on passenger flow is required. However, comprehensive data on global passenger flow remain difficult and expensive to obtain, prompting researchers to rely on scheduled flight seat capacity data or simple models of flow. This study describes the construction of an open-access modeled passenger flow matrix for all airports with a host city-population of more than 100,000 and within two transfers of air travel from various publicly available air travel datasets. Data on network characteristics, city population, and local area GDP amongst others are utilized as covariates in a spatial interaction framework to predict the air transportation flows between airports. Training datasets based on information from various transportation organizations in the United States, Canada and the European Union were assembled. A log-linear model controlling the random effects on origin, destination and the airport hierarchy was then built to predict passenger flows on the network, and compared to the results produced using previously published models. Validation analyses showed that the model presented here produced improved predictive power and accuracy compared to previously published models, yielding the highest successful prediction rate at the global scale. Based on this model, passenger flows between 1,491 airports on 644,406 unique routes were estimated in the prediction dataset. The airport node characteristics and estimated passenger flows are freely available as part of the Vector-Borne Disease Airline Importation Risk (VBD-Air) project at: www.vbd-air.com/data. PMID:23691194

  17. Evolutionary Concepts for Decentralized Air Traffic Flow Management

    NASA Technical Reports Server (NTRS)

    Adams, Milton; Kolitz, Stephan; Milner, Joseph; Odoni, Amedeo

    1997-01-01

    Alternative concepts for modifying the policies and procedures under which the air traffic flow management system operates are described, and an approach to the evaluation of those concepts is discussed. Here, air traffic flow management includes all activities related to the management of the flow of aircraft and related system resources from 'block to block.' The alternative concepts represent stages in the evolution from the current system, in which air traffic management decision making is largely centralized within the FAA, to a more decentralized approach wherein the airlines and other airspace users collaborate in air traffic management decision making with the FAA. The emphasis in the discussion is on a viable medium-term partially decentralized scenario representing a phase of this evolution that is consistent with the decision-making approaches embodied in proposed Free Flight concepts for air traffic management. System-level metrics for analyzing and evaluating the various alternatives are defined, and a simulation testbed developed to generate values for those metrics is described. The fundamental issue of modeling airline behavior in decentralized environments is also raised, and an example of such a model, which deals with the preservation of flight bank integrity in hub airports, is presented.

  18. Glow Discharge Characteristics in Transverse Supersonic Air Flow

    NASA Astrophysics Data System (ADS)

    Timerkaev, B. A.; Zalyaliev, B. R.; Saifutdinov, A. I.

    2014-11-01

    A low pressure glow discharge in a transverse supersonic gas flow of air at pressures of the order 1 torr has been experimentally studied for the case where the flow only partially fills the inter electrode gap. It is shown that the space region with supersonic gas flow has a higher concentration of gas particles and, therefore, works as a charged particle generator. The near electrode regions of glow discharge are concentrated specifically in this region. This structure of glow discharge is promising for plasma deposition of coatings under ultralow pressures

  19. Split-flow regeneration in absorptive air separation

    DOEpatents

    Weimer, Robert F.

    1987-01-01

    A chemical absorptive separation of air in multiple stage of absorption and desorption is performed with partial recycle of absorbent between stages of desorption necessary to match equilibrium conditions in the various stages of absorption. This allows reduced absorbent flow, reduced energy demand and reduced capital costs.

  20. The Wells turbine in an oscillating air flow

    SciTech Connect

    Raghunathan, S.; Ombaka,

    1984-08-01

    An experimental study of the performance of a 0.2 m diameter Wells self rectifying air turbine with NACA 0021 blades is presented. Experiments were conducted in an oscillating flowrig. The effects of Reynolds number and Strouhal number on the performance of the turbine were investigated. Finally comparison between the results with the predictions from uni-directional flow tests are made.

  1. Split-flow regeneration in absorptive air separation

    DOEpatents

    Weimer, R.F.

    1987-11-24

    A chemical absorptive separation of air in multiple stage of absorption and desorption is performed with partial recycle of absorbent between stages of desorption necessary to match equilibrium conditions in the various stages of absorption. This allows reduced absorbent flow, reduced energy demand and reduced capital costs. 4 figs.

  2. 30 CFR 57.22213 - Air flow (III mines).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Air flow (III mines). 57.22213 Section 57.22213 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Safety Standards...

  3. 30 CFR 57.22213 - Air flow (III mines).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Air flow (III mines). 57.22213 Section 57.22213 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Safety Standards...

  4. 30 CFR 57.22213 - Air flow (III mines).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Air flow (III mines). 57.22213 Section 57.22213 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Safety Standards...

  5. 30 CFR 57.22213 - Air flow (III mines).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Air flow (III mines). 57.22213 Section 57.22213 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Safety Standards...

  6. 30 CFR 57.22213 - Air flow (III mines).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Air flow (III mines). 57.22213 Section 57.22213 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Safety Standards...

  7. Ventilating-air change rate versus particulate contaminant spread

    SciTech Connect

    Langer, G.; Deitesfeld, C.A.

    1987-11-13

    This study provides information on the spread of particulate contamination from glovebox leaks in plutonium manufacturing facilities, with emphasis on the effect of ventilating-air change rate on contaminated spread. A new, very sensitive aerosol tracer technique was developed to simulate plutonium aerosol leaks and its dispersion in a room. The tracer, a submicron aerosol of phloroglucinol, does not interfere with work activity and is detected by its ability to form ice crystals in a supercooled cloud. This technique was applied in Buildings 371 and 707 plutonium production areas. The tracer spread throughout the rooms in a few minutes and reached its equilibrium concentration in 10 to 25 min. Also, to clear the room of all tracer took about the same time. In one room, tracer concentration decreased proportionally to the air change rate, while in the second one, air change rate had no effect. This points out the need for air velocity data. Also, future work must include simultaneous particle concentration measurements at several points. 4 refs., 9 figs., 2 tabs.

  8. Versatile radar measurement of the electron loss rate in air

    SciTech Connect

    Dogariu, Arthur; Shneider, Mikhail N.; Miles, Richard B.

    2013-11-25

    We present an experimental method that makes possible in-situ measurements of the electron loss rate in arbitrary gas mixtures. A weakly ionized plasma is induced via resonant multiphoton ionization of trace amounts of nitric oxide seeded into the gas, and homodyne microwave scattering detection is used to study the dynamics of the electron loss mechanisms. Using this approach, the attachment rate for electrons to molecular oxygen in room temperature, atmospheric pressure air is determined. The measured 0.76 × 10{sup 8} s{sup −1} attachment rate is in very good agreement with predictions based on literature data.

  9. Air traffic control surveillance accuracy and update rate study

    NASA Technical Reports Server (NTRS)

    Craigie, J. H.; Morrison, D. D.; Zipper, I.

    1973-01-01

    The results of an air traffic control surveillance accuracy and update rate study are presented. The objective of the study was to establish quantitative relationships between the surveillance accuracies, update rates, and the communication load associated with the tactical control of aircraft for conflict resolution. The relationships are established for typical types of aircraft, phases of flight, and types of airspace. Specific cases are analyzed to determine the surveillance accuracies and update rates required to prevent two aircraft from approaching each other too closely.

  10. Yaw rate control of an air bearing vehicle

    NASA Technical Reports Server (NTRS)

    Walcott, Bruce L.

    1989-01-01

    The results of a 6 week project which focused on the problem of controlling the yaw (rotational) rate the air bearing vehicle used on NASA's flat floor facility are summarized. Contained within is a listing of the equipment available for task completion and an evaluation of the suitability of this equipment. The identification (modeling) process of the air bearing vehicle is detailed as well as the subsequent closed-loop control strategy. The effectiveness of the solution is discussed and further recommendations are included.

  11. Changes in rabbit lacrimal gland fluid osmolarity with flow rate.

    PubMed

    Gilbard, J P; Dartt, D A

    1982-12-01

    To determine whether the osmolarity of rabbit lacrimal gland fluid (LGF) changes with flow rate, microvolumes (approximately 0.2 microliters) were collected directly from he cannulated glandular excretory duct of anesthetized rabbits. Low flow rates were obtained by collection of LGF 5 min after instillation of proparacaine: higher flow rates were obtained by stimulation with 0.45, 0.9, 3.8, or 15 micrograms of acetylcholine administered by local arterial injection. At low flow rates (less than 0.11 microliters/min), LGF osmolarity was 334 +/- 4 mOsm/L (n = 19). As flow rate increased to maximal rates (13.0 to 19.1 microliters/min), LGF osmolarity decreased to a value of 299 +/- 2 mOsm/L (n = 7). In keratoconjunctivitis sicca, increase in LGF osmolarity, as well as tear film evaporation, may contribute to elevated tear film osmolarity. PMID:7141824

  12. Ignition of hydrocarbon-air supersonic flow by volumetric ionization

    NASA Astrophysics Data System (ADS)

    Goldfeld, Marat A.; Pozdnyakov, George A.

    2015-11-01

    The paper describes the results of the electron-beam initiation of the combustion in the mixtures of hydrogen, natural gas or kerosene vapors with air. Electron beam characteristics were studied in closed volume with immobile gas. The researches included definition of an integrated current of an electronic beam, distribution of a current density and an estimation of average energy of electrons. Possibility of fuel mixtures ignition by means of this approach in the combustor at high velocity at the entrance was demonstrated. Experiments were carried out at Mach numbers of 4 and 5. Process of ignition and combustion under electron beam action was researched. It was revealed that ignition of mixture occurs after completion of electron gun operation. Data obtained have confirmed effectiveness of electron beam application for ignition of hydrogen and natural gas. The numerical simulation of the combustion of mixture in channel was carried out by means of ANSYS CFD 12.0 instrumentation on the basis of Reynolds averaged Navier-Stokes equation using SST/k-ω turbulence model. For combustion modeling, a detailed kinetic scheme with 38 reactions of 8 species was implemented taking into account finite rate chemistry. Computations have shown that the developed model allow to predict ignition of a mixture and flame propagation even at low flow temperatures.

  13. A review of air exchange rate models for air pollution exposure assessments.

    PubMed

    Breen, Michael S; Schultz, Bradley D; Sohn, Michael D; Long, Thomas; Langstaff, John; Williams, Ronald; Isaacs, Kristin; Meng, Qing Yu; Stallings, Casson; Smith, Luther

    2014-11-01

    A critical aspect of air pollution exposure assessments is estimation of the air exchange rate (AER) for various buildings where people spend their time. The AER, which is the rate of exchange of indoor air with outdoor air, is an important determinant for entry of outdoor air pollutants and for removal of indoor-emitted air pollutants. This paper presents an overview and critical analysis of the scientific literature on empirical and physically based AER models for residential and commercial buildings; the models highlighted here are feasible for exposure assessments as extensive inputs are not required. Models are included for the three types of airflows that can occur across building envelopes: leakage, natural ventilation, and mechanical ventilation. Guidance is provided to select the preferable AER model based on available data, desired temporal resolution, types of airflows, and types of buildings included in the exposure assessment. For exposure assessments with some limited building leakage or AER measurements, strategies are described to reduce AER model uncertainty. This review will facilitate the selection of AER models in support of air pollution exposure assessments. PMID:23715084

  14. A stagnation pressure probe for droplet-laden air flow

    NASA Technical Reports Server (NTRS)

    Murthy, S. N. B.; Leonardo, M.; Ehresman, C. M.

    1985-01-01

    It is often of interest in a droplet-laden gas flow to obtain the stagnation pressure of both the gas phase and the mixture. A flow-decelerating probe (TPF), with separate, purged ports for the gas phase and the mixture and with a bleed for accumulating liquid at the closed end, has been developed. Measurements obtained utilizing the TPF in a nearly isothermal air-water droplet mixture flow in a smooth circular pipe under various conditions of flow velocity, pressure, liquid concentration and droplet size are presented and compared with data obtained under identical conditions with a conventional, gas phase stagnation pressure probe (CSP). The data obtained with the CSP and TPF probes are analyzed to determine the applicability of the two probes in relation to the multi-phase characteristics of the flow and the geometry of the probe.

  15. Specific Impulse and Mass Flow Rate Error

    NASA Technical Reports Server (NTRS)

    Gregory, Don A.

    2005-01-01

    Specific impulse is defined in words in many ways. Very early in any text on rocket propulsion a phrase similar to .specific impulse is the thrust force per unit propellant weight flow per second. will be found.(2) It is only after seeing the mathematics written down does the definition mean something physically to scientists and engineers responsible for either measuring it or using someone.s value for it.

  16. Influence of impactor operating flow rate on particle size distribution of four jet nebulizers.

    PubMed

    Zhou, Yue; Brasel, Trevor L; Kracko, Dean; Cheng, Yung-Sung; Ahuja, Amitkumar; Norenberg, Jeffrey P; Kelly, H William

    2007-01-01

    When a nebulizer is evaluated by the Andersen Cascade Impactor (ACI), the flow rate is generally maintained at 28.3 L/min, as recommended by the manufacturer. However, the nebulizer flow rate that a patient inhales is only around 18 L/min. Because the drive flow of a nebulizer is approximately 6-8 L/min, the nebulized drug is mixed with outside air when delivered. Evaluating impactor performance at the 28.3 L/min flow rate is less than ideal because an additional 10 L/min of outside air is mixed with the drug, thereby affecting the drug size distribution and dose before inhalation and deposition in the human lung. In this study we operated the ACI at an 18.0 L/min flow rate to test whether the effect of the changing ambient humidity was being exaggerated by the 28.3 L/min flow rate. The study was carried out at three different relative humidity levels and two different impactor flow rates with four commercially available nebulizers. The mass median aerodynamic diameter (MMAD) and the geometric standard deviation (GSD) of the droplets were found to increase when the impactor was operated at a flow rate of 18 L/min compared to that of 28.3 L/min. The higher MMAD and GSD could cause the patient to inhale less of the drug than expected if the nebulizer was evaluated by the ACI at the operating flow rate of 28.3 L/min. PMID:17763140

  17. Flow rates through earthen, geomembrane & composite cut-off walls

    SciTech Connect

    Tachavises, C.; Benson, C.H.

    1997-12-31

    Flow rates through soil-bentonite (SIB), geomembrane (GM), and composite geomembrane-soil (CGS) cut-off walls were determined using a numerical model of ground water flow. Various geological and wall conditions were simulated. Results of the simulations show that flow rates past all wall types are affected by hydraulic conductivities of the aquifer and underlying confining layer. Flow rates past GM walls with perfect joints are very low, provided the confining layer has low hydraulic conductivity. However, if a small fraction of the joints are defective, GM walls can be ineffective in blocking flow. CGS walls with a low hydraulic conductivity shell are less sensitive to joint defects. CGS walls with good shells typically have lower flow rates than SB and GM walls, even if the CGS wall contains defective joints.

  18. Parametric Studies of Flow Separation using Air Injection

    NASA Technical Reports Server (NTRS)

    Zhang, Wei

    2004-01-01

    Boundary Layer separation causes the airfoil to stall and therefore imposes dramatic performance degradation on the airfoil. In recent years, flow separation control has been one of the active research areas in the field of aerodynamics due to its promising performance improvements on the lifting device. These active flow separation control techniques include steady and unsteady air injection as well as suction on the airfoil surface etc. This paper will be focusing on the steady and unsteady air injection on the airfoil. Although wind tunnel experiments revealed that the performance improvements on the airfoil using injection techniques, the details of how the key variables such as air injection slot geometry and air injection angle etc impact the effectiveness of flow separation control via air injection has not been studied. A parametric study of both steady and unsteady air injection active flow control will be the main objective for this summer. For steady injection, the key variables include the slot geometry, orientation, spacing, air injection velocity as well as the injection angle. For unsteady injection, the injection frequency will also be investigated. Key metrics such as lift coefficient, drag coefficient, total pressure loss and total injection mass will be used to measure the effectiveness of the control technique. A design of experiments using the Box-Behnken Design is set up in order to determine how each of the variables affects each of the key metrics. Design of experiment is used so that the number of experimental runs will be at minimum and still be able to predict which variables are the key contributors to the responses. The experiments will then be conducted in the 1ft by 1ft wind tunnel according to the design of experiment settings. The data obtained from the experiments will be imported into JMP, statistical software, to generate sets of response surface equations which represent the statistical empirical model for each of the metrics as

  19. 40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false SSV, CFV, and PDP molar flow rate calculations. 1065.642 Section 1065.642 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.642...

  20. 40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false SSV, CFV, and PDP molar flow rate calculations. 1065.642 Section 1065.642 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.642...

  1. 40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false SSV, CFV, and PDP molar flow rate calculations. 1065.642 Section 1065.642 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.642...

  2. 40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false SSV, CFV, and PDP molar flow rate calculations. 1065.642 Section 1065.642 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.642...

  3. Flow characteristics of an inclined air-curtain range hood in a draft

    PubMed Central

    CHEN, Jia-Kun

    2015-01-01

    The inclined air-curtain technology was applied to build an inclined air-curtain range hood. A draft generator was applied to affect the inclined air-curtain range hood in three directions: lateral (θ=0°), oblique (θ=45°), and front (θ=90°). The three suction flow rates provided by the inclined air-curtain range hood were 10.1, 10.9, and 12.6 m3/min. The laser-assisted flow visualization technique and the tracer-gas test method were used to investigate the performance of the range hood under the influence of a draft. The results show that the inclined air-curtain range hood has a strong ability to resist the negative effect of a front draft until the draft velocity is greater than 0.5 m/s. The oblique draft affected the containment ability of the inclined air-curtain range hood when the draft velocity was larger than 0.3 m/s. When the lateral draft effect was applied, the capture efficiency of the inclined air-curtain range hood decreased quickly in the draft velocity from 0.2 m/s to 0.3 m/s. However, the capture efficiencies of the inclined air-curtain range hood under the influence of the front draft were higher than those under the influence of the oblique draft from 0.3 m/s to 0.5 m/s. PMID:25810445

  4. The Effects of Air Pollution on Ischemic Stroke Admission Rate.

    PubMed

    Alimohammadi, Hossein; Fakhri, Sara; Derakhshanfar, Hojjat; Hosseini-Zijoud, Seyed-Mostafa; Safari, Saeed; Hatamabadi, Hamid Reza

    2016-01-01

    The present study aimed to determine the relationship between the level of air pollutants and the rate of ischemic stroke (IS) admissions to hospitals. In this retrospective cross-sectional study, stroke admissions (January-March 2012 and 2013) to an emergency department and air pollution and meteorological data were gathered. The relationship between air pollutant levels and hospital admission rates were evaluated using the generalize additive model. In all 379 patients with IS were referred to the hospital (52.5% male; mean age 68.2±13.3 years). Both transient (p<0.001) and long-term (p<0.001) rises in CO level increases the risk of IS. Increased weekly (p<0.001) and monthly (p<0.001) average O3 levels amplifies this risk, while a transient increase in NO2 (p<0.001) and SO2 (p<0.001) levels has the same effect. Long-term changes in PM10 (p<0.001) and PM2.5 (p<0.001) also increase the risk of IS. The findings showed that the level of air pollutants directly correlates with the number of stroke admissions to the emergency department. PMID:26866000

  5. The Effects of Air Pollution on Ischemic Stroke Admission Rate

    PubMed Central

    Alimohammadi, Hossein; Fakhri, Sara; Derakhshanfar, Hojjat; Hosseini-Zijoud, Seyed-Mostafa; Safari, Saeed

    2016-01-01

    The present study aimed to determine the relationship between the level of air pollutants and the rate of ischemic stroke (IS) admissions to hospitals. In this retrospective cross-sectional study, stroke admissions (January-March 2012 and 2013) to an emergency department and air pollution and meteorological data were gathered. The relationship between air pollutant levels and hospital admission rates were evaluated using the generalize additive model. In all 379 patients with IS were referred to the hospital (52.5% male; mean age 68.2±13.3 years). Both transient (p<0.001) and long-term (p<0.001) rises in CO level increases the risk of IS. Increased weekly (p<0.001) and monthly (p<0.001) average O3 levels amplifies this risk, while a transient increase in NO2 (p<0.001) and SO2 (p<0.001) levels has the same effect. Long-term changes in PM10 (p<0.001) and PM2.5 (p<0.001) also increase the risk of IS. The findings showed that the level of air pollutants directly correlates with the number of stroke admissions to the emergency department. PMID:26866000

  6. Flow over a Modern Ram-Air Parachute Canopy

    NASA Astrophysics Data System (ADS)

    Mohammadi, Mohammad; Johari, Hamid

    2010-11-01

    The flow field on the central section of a modern ram-air parachute canopy was examined numerically using a finite-volume flow solver coupled with the one equation Spalart-Allmaras turbulence model. Ram-air parachutes are used for guided airdrop applications, and the canopy resembles a wing with an open leading edge for inflation. The canopy surfaces were assumed to be impermeable and rigid. The flow field consisted of a vortex inside the leading edge opening which effectively closed off the canopy and diverted the flow around the leading edge. The flow experienced a rather bluff leading edge in contrast to the smooth leading of an airfoil, leading to a separation bubble on the lower lip of the canopy. The flow inside the canopy was stagnant beyond the halfway point. The section lift coefficient increased linearly with the angle of attack up to 8.5 and the lift curve slope was about 8% smaller than the baseline airfoil. The leading edge opening had a major effect on the drag prior to stall; the drag is at least twice the baseline airfoil drag. The minimum drag of the section occurs over the angle of attack range of 3 -- 7 .

  7. Air Controlman 3 and 2: Naval Rate Training Manual and Nonresident Career Course.

    ERIC Educational Resources Information Center

    Naval Education and Training Command, Pensacola, FL.

    The Rate Training Manual is one of a series of training manuals prepared for enlisted personnel of the Navy and Naval Reserve studying for advancement in the Air Controlman (AC) rating to Air Controlman Third and Second Class. Chapter 1 discusses air controlman qualifications, the enlisted rating structure, the Air Controlman rating, references…

  8. Air Flow and Pressure Drop Measurements Across Porous Oxides

    NASA Technical Reports Server (NTRS)

    Fox, Dennis S.; Cuy, Michael D.; Werner, Roger A.

    2008-01-01

    This report summarizes the results of air flow tests across eight porous, open cell ceramic oxide samples. During ceramic specimen processing, the porosity was formed using the sacrificial template technique, with two different sizes of polystyrene beads used for the template. The samples were initially supplied with thicknesses ranging from 0.14 to 0.20 in. (0.35 to 0.50 cm) and nonuniform backside morphology (some areas dense, some porous). Samples were therefore ground to a thickness of 0.12 to 0.14 in. (0.30 to 0.35 cm) using dry 120 grit SiC paper. Pressure drop versus air flow is reported. Comparisons of samples with thickness variations are made, as are pressure drop estimates. As the density of the ceramic material increases the maximum corrected flow decreases rapidly. Future sample sets should be supplied with samples of similar thickness and having uniform surface morphology. This would allow a more consistent determination of air flow versus processing parameters and the resulting porosity size and distribution.

  9. Tracheal Mucus Flow Rates in Experimental Bronchitis in Rats

    PubMed Central

    Lightowler, Norah M.; Williams, J. R. B.

    1969-01-01

    The flow of mucus in the trachea of rats previously exposed to an atmosphere of SO2 in air was measured and correlated with the histological changes in the trachea, bronchi and lungs. Reduction in the speed of mucus flow in the exposed trachea was found with increasing severity of bronchopulmonary changes. ImagesFigs. 9-12Figs. 6-7Figs. 2-5 PMID:5772066

  10. Fuel Spray and Flame Formation in a Compression-Ignition Engine Employing Air Flow

    NASA Technical Reports Server (NTRS)

    Rothrock, A M; Waldron, C D

    1937-01-01

    The effects of air flow on fuel spray and flame formation in a high-speed compression-ignition engine have been investigated by means of the NACA combustion apparatus. The process was studied by examining high-speed motion pictures taken at the rate of 2,200 frames a second. The combustion chamber was of the flat-disk type used in previous experiments with this apparatus. The air flow was produced by a rectangular displacer mounted on top of the engine piston. Three fuel-injection nozzles were tested: a 0.020-inch single-orifice nozzle, a 6-orifice nozzle, and a slit nozzle. The air velocity within the combustion chamber was estimated to reach a value of 425 feet a second. The results show that in no case was the form of the fuel spray completely destroyed by the air jet although in some cases the direction of the spray was changed and the spray envelope was carried away by the moving air. The distribution of the fuel in the combustion chamber of a compression-ignition engine can be regulated to some extent by the design of the combustion chamber, by the design of the fuel-injection nozzle, and by the use of air flow.

  11. Uncertainty Analysis for a Virtual Flow Meter Using an Air-Handling Unit Chilled Water Valve

    SciTech Connect

    Song, Li; Wang, Gang; Brambley, Michael R.

    2013-04-28

    A virtual water flow meter is developed that uses the chilled water control valve on an air-handling unit as a measurement device. The flow rate of water through the valve is calculated using the differential pressure across the valve and its associated coil, the valve command, and an empirically determined valve characteristic curve. Thus, the probability of error in the measurements is significantly greater than for conventionally manufactured flow meters. In this paper, mathematical models are developed and used to conduct uncertainty analysis for the virtual flow meter, and the results from the virtual meter are compared to measurements made with an ultrasonic flow meter. Theoretical uncertainty analysis shows that the total uncertainty in flow rates from the virtual flow meter is 1.46% with 95% confidence; comparison of virtual flow meter results with measurements from an ultrasonic flow meter yielded anuncertainty of 1.46% with 99% confidence. The comparable results from the theoretical uncertainty analysis and empirical comparison with the ultrasonic flow meter corroborate each other, and tend to validate the approach to computationally estimating uncertainty for virtual sensors introduced in this study.

  12. Cooling rates of living and killed chicken and quail eggs in air and in helium-oxygen gas mixture.

    PubMed

    Tazawa, H; Turner, J S; Paganelli, C V

    1988-01-01

    1. In a helium atmosphere, heat is dissipated from a surface 3.5 times faster than it is in air. Eggs in a helium-oxygen atmosphere cool only 1.4 times faster than they cool in air. This signifies that internal resistance to heat flow is a significant factor in the cooling rates of eggs. 2. Heat flow occurs inside an egg in two ways: by conduction through the tissues and in flowing blood. Killing an embryo stops the latter, but not the former. Eggs cool more slowly after they have been killed, signifying that blood flow can be an important component in an egg's internal flows of heat. 3. Blood flow should be a relatively more important component of heat flow in large eggs than in small eggs. The difference in conductance between living and killed eggs is larger in 60 g chicken eggs than it is in 10 g quail eggs. PMID:2900113

  13. Asthma ski day: cold air sports safe with peak flow monitoring.

    PubMed

    Silvers, W; Morrison, M; Wiener, M

    1994-08-01

    The Colorado Asthma Ski Day, an annual cross-country and alpine skiing event, encourages children with asthma to participate fully in outdoor winter sports. Since cold air and exercise can trigger bronchospasm, we examined the peak expiratory flow rates of 80 children who attended Asthma Ski Day 1992 or Asthma Ski Day 1993 to establish a safety profile for this event. Peak expiratory flow rates were measured prior to skiing, at lunchtime, and at the end of the day's activities. We asked the children to pretreat with their regular medications, as prescribed by their physicians, to use their bronchodilator inhalers p.r.n., and to report to our medical station if an episode of acute asthma occurred. The average age of the participants was 9.5 years, and the average baseline daytime peak flow rate was 100.03% of predicted. The average percent change in peak flow rates during the day was an increase of 5.00%. Our results demonstrate that with medical supervision, peak expiratory flow rate monitoring, and properly administered medications, peak flow rates can be stabilized and even improve during cold-weather exercise to an extent that safety concerns need not restrict children with asthma from engaging in exercise or cold-weather sports. The Colorado Asthma Ski Day can serve as a model event for other organizations that want to promote outdoor activities for children with asthma. PMID:8067591

  14. Flow regime classification in air magnetic fluid two-phase flow

    NASA Astrophysics Data System (ADS)

    Kuwahara, T.; DeVuyst, F.; Yamaguchi, H.

    2008-05-01

    A new experimental/numerical technique of classification of flow regimes (flow patterns) in air-magnetic fluid two-phase flow is proposed in the present paper. The proposed technique utilizes the electromagnetic induction to obtain time-series signals of the electromotive force, allowing us to make a non-contact measurement. Firstly, an experiment is carried out to obtain the time-series signals in a vertical upward air-magnetic fluid two-phase flow. The signals obtained are first treated using two kinds of wavelet transforms. The data sets treated are then used as input vectors for an artificial neural network (ANN) with supervised training. In the present study, flow regimes are classified into bubbly, slug, churn and annular flows, which are generally the main flow regimes. To validate the flow regimes, a visualization experiment is also performed with a glycerin solution that has roughly the same physical properties, i.e., kinetic viscosity and surface tension, as a magnetic fluid used in the present study. The flow regimes from the visualization are used as targets in an ANN and also used in the estimation of the accuracy of the present method. As a result, ANNs using radial basis functions are shown to be the most appropriate for the present classification of flow regimes, leading to small classification errors.

  15. Flow regime classification in air-magnetic fluid two-phase flow.

    PubMed

    Kuwahara, T; De Vuyst, F; Yamaguchi, H

    2008-05-21

    A new experimental/numerical technique of classification of flow regimes (flow patterns) in air-magnetic fluid two-phase flow is proposed in the present paper. The proposed technique utilizes the electromagnetic induction to obtain time-series signals of the electromotive force, allowing us to make a non-contact measurement. Firstly, an experiment is carried out to obtain the time-series signals in a vertical upward air-magnetic fluid two-phase flow. The signals obtained are first treated using two kinds of wavelet transforms. The data sets treated are then used as input vectors for an artificial neural network (ANN) with supervised training. In the present study, flow regimes are classified into bubbly, slug, churn and annular flows, which are generally the main flow regimes. To validate the flow regimes, a visualization experiment is also performed with a glycerin solution that has roughly the same physical properties, i.e., kinetic viscosity and surface tension, as a magnetic fluid used in the present study. The flow regimes from the visualization are used as targets in an ANN and also used in the estimation of the accuracy of the present method. As a result, ANNs using radial basis functions are shown to be the most appropriate for the present classification of flow regimes, leading to small classification errors. PMID:21694270

  16. Accurate burner air flow measurement for low NO{sub x} burners

    SciTech Connect

    Earley, D.; Penterson, C.

    1998-07-01

    In 1990, Congress enacted an amendment to the Clean Air Act that required reductions in NO{sub x} emissions through the application of low NO{sub x} burner systems on fossil fueled utility steam generators. For most of the existing steam generator population, the original burning equipment incorporated highly turbulent burners that created significant in-furnace flame interaction. Thus, the measurement and control of air flow to the individual burners was much less critical than in recent years with low NO{sub x} combustion systems. With low NO{sub x} systems, the reduction of NO{sub x} emissions, as well as minimizing flyash unburned carbon levels, is very much dependent on the ability to control the relative ratios of air and fuel on a per-burner basis and their rate of mixing, particularly in the near burner zones. Air Monitor Corporation (AMC) and DB Riley, Inc. (DBR), and a large Midwestern electric utility have successfully developed and applied AMC's equipment to low NO{sub x} coal burners in order to enhance NO{sub x} control combustion systems. The results have improved burner optimization and provided real time continuous air flow balancing capability and the control of individual burner stoichiometries. To date, these enhancements have been applied to wall-fired low NO{sub x} systems for balancing individual burner air flows in a common windbox and to staged combustion systems. Most recently, calibration testing in a wind tunnel facility of AMC's individual burner air measurement (IBAM{trademark}) probes installed in DB Riley's low NO{sub x} CCV{reg{underscore}sign} burners has demonstrated the ability to produce reproducible and consistent air flow measurement accurate to within 5%. This paper will summarize this product development and quantify the benefits of its application to low NO{sub x} combustion systems.

  17. Vitreous flow rates through dual pneumatic cutters: effects of duty cycle and cut rate

    PubMed Central

    Abulon, Dina Joy K

    2015-01-01

    Purpose We aimed to investigate effects of instrument settings on porcine vitreous flow rates through dual pneumatic high-speed vitrectomy probes. Methods The CONSTELLATION® Vision System was tested with 250, 450, and 650 mmHg of vacuum using six ULTRAVIT® vitrectomy probes of each diameter (25+®, 25, 23, and 20 gauge) operated from 500 cuts per minute (cpm) up to 5,000 cpm. Duty cycle modes tested included biased open, 50/50, and biased closed. Flow rates were calculated by assessing the change in weight of porcine eyes during vitreous aspiration. Volumetric flow rate was measured with a computer-connected electronic scale. Results At lower cut rates, the biased open mode produced higher flow than did the 50/50 mode, which produced higher flow than did the biased closed mode. In the biased closed and 50/50 modes, vitreous flow rates tended to increase with increasing cut rate. Vitreous flow rates in the biased open duty cycle mode remained relatively constant across cut rates. Conclusion Vitreous flow rates through dual pneumatic vitrectomy probes could be manipulated by changing the duty cycle modes on the vitrectomy system. Differences in duty cycle behavior suggest that high-speed cut rates of 5,000 cpm may optimize vitreous aspiration. PMID:25709386

  18. Interrelationships of petiole air canal architecture, water depth and convective air flow in Nymphaea odorata (Nymphaeaceae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Premise of the study--Nymphaea odorata grows in water up to 2 m deep, producing fewer, larger leaves in deeper water. This species has a convective flow system that moves gases from younger leaves through submerged parts to older leaves, aerating submerged parts. Petiole air canals are in the conv...

  19. Character of energy flow in air shower core

    NASA Technical Reports Server (NTRS)

    Mizushima, K.; Asakimori, K.; Maeda, T.; Kameda, T.; Misaki, Y.

    1985-01-01

    Energy per charged particle near the core of air showers was measured by 9 energy flow detectors, which were the combination of Cerenkov counters and scintillators. Energy per particle of each detector was normalized to energy at 2m from the core. The following results were obtained as to the energy flow: (1) integral frequency distribution of mean energy per particle (averaged over 9 detectors) is composed of two groups separated distinctly; and (2) showers contained in one group show an anisotropy of arrival direction.

  20. Vision and air flow combine to streamline flying honeybees

    PubMed Central

    Taylor, Gavin J.; Luu, Tien; Ball, David; Srinivasan, Mandyam V.

    2013-01-01

    Insects face the challenge of integrating multi-sensory information to control their flight. Here we study a ‘streamlining' response in honeybees, whereby honeybees raise their abdomen to reduce drag. We find that this response, which was recently reported to be mediated by optic flow, is also strongly modulated by the presence of air flow simulating a head wind. The Johnston's organs in the antennae were found to play a role in the measurement of the air speed that is used to control the streamlining response. The response to a combination of visual motion and wind is complex and can be explained by a model that incorporates a non-linear combination of the two stimuli. The use of visual and mechanosensory cues increases the strength of the streamlining response when the stimuli are present concurrently. We propose this multisensory integration will make the response more robust to transient disturbances in either modality. PMID:24019053

  1. Effects of air flow directions on composting process temperature profile

    SciTech Connect

    Kulcu, Recep; Yaldiz, Osman

    2008-07-01

    In this study, chicken manure mixed with carnation wastes was composted by using three different air flow directions: R1-sucking (downward), R2-blowing (upward) and R3-mixed. The aim was to find out the most appropriate air flow direction type for composting to provide more homogenous temperature distribution in the reactors. The efficiency of each aeration method was evaluated by monitoring the evolution of parameters such as temperature, moisture content, CO{sub 2} and O{sub 2} ratio in the material and dry material losses. Aeration of the reactors was managed by radial fans. The results showed that R3 resulted in a more homogenous temperature distribution and high dry material loss throughout the composting process. The most heterogeneous temperature distribution and the lowest dry material loss were obtained in R2.

  2. Electron concentration distribution in a glow discharge in air flow

    NASA Astrophysics Data System (ADS)

    Mukhamedzianov, R. B.; Gaisin, F. M.; Sabitov, R. A.

    1989-04-01

    Electron concentration distributions in a glow discharge in longitudinal and vortex air flows are determined from the attenuation of the electromagnetic wave passing through the plasma using microwave probes. An analysis of the distribution curves obtained indicates that electron concentration decreases in the direction of the anode. This can be explained by charge diffusion toward the chamber walls and electron recombination and sticking within the discharge.

  3. Methods of Visually Determining the Air Flow Around Airplanes

    NASA Technical Reports Server (NTRS)

    Gough, Melvin N; Johnson, Ernest

    1932-01-01

    This report describes methods used by the National Advisory Committee for Aeronautics to study visually the air flow around airplanes. The use of streamers, oil and exhaust gas streaks, lampblack and kerosene, powdered materials, and kerosene smoke is briefly described. The generation and distribution of smoke from candles and from titanium tetrachloride are described in greater detail because they appear most advantageous for general application. Examples are included showing results of the various methods.

  4. Numerical characterization of the hydrodynamics and thermal behavior of air flow in flexible air distribution system

    NASA Astrophysics Data System (ADS)

    Gharehdaghi, Samad; Moujaes, Samir

    2013-10-01

    Flexible duct air distribution systems are used in a large percentage of residential and small commercial buildings in the United States . Very few empirical or predictive data are available though to help provide the HVAC design engineer with reliable information . Moreover, because of the ducts flexibility, the shapes of these ducts offer a different set of operating fluid flow and thermal conditions from traditional smooth metal ducts. Hence, both the flow field and heat transfer through this kind of ducts are much more complex and merit to be analyzed from a numerical predictive approach. The aim of this research paper is to compute some of the hydrodynamic and heat transfer characteristics of the air flow inside these ducts over a range of Re numbers commonly used in the flow conditions of these air distribution systems. The information resulting from this CFD simulation, where a κ-ɛ turbulent model is used to predict the flow conditions, provide pressure drop and average convective heat transfer coefficients that exist in these ducts and was compared to previously found data. Circulation zones in the depressions of these ducts are found to exist which are suspected of influencing the pressured drop and heat transfer coefficients as compared to smooth ducts. The results show that fully developed conditions exist much earlier with regard to the inlet for both hydrodynamic and thermal entrance regions than what would be expected in smooth ducts under the same turbulent conditions.

  5. Turbine flow sensor for volume-flow rate verification in MR.

    PubMed

    Frayne, R; Holdsworth, D W; Smith, R F; Kasrai, R; Larsen, J P; Rutt, B K

    1994-09-01

    A turbine flow sensor for MR flow experiments has been evaluated using reference volume-flow rate measurements obtained using an electromagnetic (EM) flow meter measurements and simultaneous phase contrast (PC) MR acquisitions. After calibration, the device was found to have accuracy (compared with the EM flow meter), linearity, and precision of better than +/- 1%, +/- 3.5%, 3.5%, respectively, in constant flow mode (0 to 30 ml s-1). The frequency response of the flow sensor was flat (within +/- 10%) up to 13.9 Hz. Volume-flow rate measurements on constant and simulated physiologic flow waveforms were in close agreement with both the electromagnetic (EM) flow meter and the gated MR PC estimates. PMID:7984075

  6. Measurement of air distribution and void fraction of an upwards air-water flow using electrical resistance tomography and a wire-mesh sensor

    NASA Astrophysics Data System (ADS)

    Olerni, Claudio; Jia, Jiabin; Wang, Mi

    2013-03-01

    Measurements on an upwards air-water flow are reported that were obtained simultaneously with a dual-plane electrical resistance tomograph (ERT) and a wire-mesh sensor (WMS). The ultimate measurement target of both ERT and WMS is the same, the electrical conductivity of the medium. The ERT is a non-intrusive device whereas the WMS requires a net of wires that physically crosses the flow. This paper presents comparisons between the results obtained simultaneously from the ERT and the WMS for evaluation and calibration of the ERT. The length of the vertical testing pipeline section is 3 m with an internal diameter of 50 mm. Two distinct sets of air-water flow rate scenarios, bubble and slug regimes, were produced in the experiments. The fast impedance camera ERT recorded the data at an approximate time resolution of 896 frames per second (fps) per plane in contrast with the 1024 fps of the wire-mesh sensor WMS200. The set-up of the experiment was based on well established knowledge of air-water upwards flow, particularly the specific flow regimes and wall peak effects. The local air void fraction profiles and the overall air void fraction were produced from two systems to establish consistency for comparison of the data accuracy. Conventional bulk flow measurements in air mass and electromagnetic flow metering, as well as pressure and temperature, were employed, which brought the necessary calibration to the flow measurements. The results show that the profiles generated from the two systems have a certain level of inconsistency, particularly in a wall peak and a core peak from the ERT and WMS respectively, whereas the two tomography instruments achieve good agreement on the overall air void fraction for bubble flow. For slug flow, when the void fraction is over 30%, the ERT underestimates the void fraction, but a linear relation between ERT and WMS is still observed.

  7. Controlling hydrophilicity of polymer film by altering gas flow rate in atmospheric-pressure homogeneous plasma

    NASA Astrophysics Data System (ADS)

    Kang, Woo Seok; Hur, Min; Lee, Jae-Ok; Song, Young-Hoon

    2014-03-01

    This paper reports on controlling the hydrophilicity of polyimide films using atmospheric-pressure homogeneous plasmas by changing only the gas flow rate. The gas flow changed the discharge atmosphere by mixing the feed gas with ambient air because of the particular geometry of the reactor developed for the study, and a low gas flow rate was found to be favorable because it generated abundant nitrogen or oxygen species that served as sources of hydrophilic functional groups over the polymer surface. After low-gas-flow plasma treatment, the polymer surface exhibited hydrophilic characteristics with increased surface roughness and enhanced chemical properties owing to the surface addition of functional groups. Without adding any reactive gases or requiring high plasma power and longer treatment time, the developed reactor with low-gas-flow operation offered effective and economical wettability control of polyimide films.

  8. The air-kerma rate constant of 192Ir.

    PubMed

    Ninković, M M; Raiĉevìć, J J

    1993-01-01

    The air-kerma rate constant gamma delta (and its precursors), as one of the basic radiation characteristics of 192Ir, was determined by many authors. Analysis of accessible data on this quantity led us to the conclusion that published data strongly disagree. That is the reason we calculated this quantity on the basis of our and many other authors' gamma-ray spectral data and the latest data for mass energy-transfer coefficients for air. In this way, a value was obtained for gamma delta of 30.0 +/- 0.9 a Gy m2 s-1 Bq-1 for an unshielded 192Ir source and 27.8 +/- 0.9 a Gy m2s -1Bq-1 for a standard packaged radioactive source taking into account attenuation of gamma rays in the platinum source wall. PMID:8416220

  9. Flow over a Ram-Air Parachute Canopy

    NASA Astrophysics Data System (ADS)

    Eslambolchi, Ali; Johari, Hamid

    2012-11-01

    The flow field over a full-scale, ram-air personnel parachute canopy was investigated numerically using a finite-volume flow solver coupled with the Spalart-Allmaras turbulence model. Ram-air parachute canopies resemble wings with arc-anhedral, surface protuberances, and an open leading edge for inflation. The rectangular planform canopy had an aspect ratio of 2.2 and was assumed to be rigid and impermeable. The chord-based Reynolds number was 3.2 million. Results indicate that the oncoming flow barely penetrates the canopy opening, and creates a large separation bubble below the lower lip of canopy. A thick boundary layer exists over the entire lower surface of the canopy. The flow over the upper surface of the canopy remains attached for an extended fraction of the chord. Lift increases linearly with angle of attack up to about 12 degrees. To assess the capability of lifting-line theory in predicting the forces on the canopy, the lift and drag data from a two-dimensional simulation of the canopy profile were extended using finite-wing expressions and compared with the forces from the present simulations. The finite-wing predicted lift and drag trends compare poorly against the full-span simulation, and the maximum lift-to-drag ratio is over-predicted by 36%. Sponsored by the US Army NRDEC.

  10. Thermistor based, low velocity isothermal, air flow sensor

    NASA Astrophysics Data System (ADS)

    Cabrita, Admésio A. C. M.; Mendes, Ricardo; Quintela, Divo A.

    2016-03-01

    The semiconductor thermistor technology is applied as a flow sensor to measure low isothermal air velocities (<2 ms-1). The sensor is subjected to heating and cooling cycles controlled by a multifunctional timer. In the heating stage, the alternating current of a main AC power supply source guarantees a uniform thermistor temperature distribution. The conditioning circuit assures an adequate increase of the sensors temperature and avoids the thermal disturbance of the flow. The power supply interruption reduces the consumption from the source and extends the sensors life time. In the cooling stage, the resistance variation of the flow sensor is recorded by the measuring chain. The resistive sensor parameters proposed vary significantly and feature a high sensitivity to the flow velocity. With the aid of a computer, the data transfer, storage and analysis provides a great advantage over the traditional local anemometer readings. The data acquisition chain has a good repeatability and low standard uncertainties. The proposed method measures isothermal air mean velocities from 0.1 ms-1 to 2 ms-1 with a standard uncertainty error less than 4%.

  11. Expected rates with mini-arrays for air showers

    NASA Technical Reports Server (NTRS)

    Hazen, W. E.

    1985-01-01

    As a guide in the design of mini-arrays used to exploit the Linsley effect in the study of air showers, it is useful to calculate the expected rates. The results can aid in the choice of detectors and their placement or in predicting the utility of existing detector systems. Furthermore, the potential of the method can be appraised for the study of large showers. Specifically, we treat the case of a mini-array of dimensions small enough compared to the distance of axes of showers of interest so that it can be considered a point detector. The input information is taken from the many previous studies of air showers by other groups. The calculations will give: (1) the expected integral rate, F(sigma, rho), for disk thickness, sigma, or rise time, t sub 1/2, with local particle density, rho, as a parameter; (2) the effective detection area A(N) with sigma (min) and rho (min) and rho (min) as parameters; (3) the expected rate of collection of data F sub L (N) versus shower size, N.

  12. Fluid/Vapor Separator for Variable Flow Rates

    NASA Technical Reports Server (NTRS)

    Lee, J. M.; Chuang, C.; Frederking, T. H.; Brown, G. S.; Kamioka, Y.; Vorreiter, J.

    1984-01-01

    Shutter varies gas throughput of porous plug. Variable area exposed on porous plug allows to pass varying rates of vapor flow while blocking flow of liquid helium II from cryogenic bath. Applications in refining operations, industrial chemistry, and steam-powered equipment.

  13. The Effects of Bottom Blowing Gas Flow Rate Distribution During the Steelmaking Converter Process on Mixing Efficiency

    NASA Astrophysics Data System (ADS)

    Chu, Kuan-Yu; Chen, Hsing-Hao; Lai, Po-Han; Wu, Hsuan-Chung; Liu, Yung-Chang; Lin, Chi-Cheng; Lu, Muh-Jung

    2016-04-01

    Featuring the advantages of top-blown and bottom-blown oxygen converters, top and bottom combined blown converters are mainstream devices used in steelmaking converter. This study adopted the FLUENT software to develop a numerical model that simulates 3D multiphase flows of gas (air and argon), liquid steel, and slag. Ten numerical experiments were conducted to analyze the effects that the bottom blowing gas flow rate distribution patterns (uniform, linear fixed total flow rate, linear fixed maximal flow rate, and V-type) and bottom blowing gas flow distribution gradients of combined blown converters exert on slag surface stirring heights, flow field patterns, simulation system dynamic pressures, mixing time, and liquid steel-slag interface velocity. The simulation results indicated that the mixing efficiency was highest for the linear fixed total flow rate, followed by the linear fixed maximal flow rate, V-type, and uniform patterns. The bottom blowing gas flow rate distribution exhibited linear patterns and large gradients, and high bottom blowing total flow rates increased the mixing efficiency substantially. In addition, the results suggested that even when bottom blowing total flow rate was reduced, adopting effective bottom blowing gas flow rate distribution patterns and gradients could improve the mixing efficiency.

  14. Laminar Flow Supersonic Wind Tunnel primary air injector

    NASA Technical Reports Server (NTRS)

    Smith, Brooke Edward

    1993-01-01

    This paper describes the requirements, design, and prototype testing of the flex-section and hinge seals for the Laminar Flow Supersonic Wind Tunnel Primary Injector. The supersonic atmospheric primary injector operates between Mach 1.8 and Mach 2.2 with mass-flow rates of 62 to 128 lbm/s providing the necessary pressure reduction to operate the tunnel in the desired Reynolds number (Re) range.

  15. Evaluation of IOM personal sampler at different flow rates.

    PubMed

    Zhou, Yue; Cheng, Yung-Sung

    2010-02-01

    The Institute of Occupational Medicine (IOM) personal sampler is usually operated at a flow rate of 2.0 L/min, the rate at which it was designed and calibrated, for sampling the inhalable mass fraction of airborne particles in occupational environments. In an environment of low aerosol concentrations only small amounts of material are collected, and that may not be sufficient for analysis. Recently, a new sampling pump with a flow rate up to 15 L/min became available for personal samplers, with the potential of operating at higher flow rates. The flow rate of a Leland Legacy sampling pump, which operates at high flow rates, was evaluated and calibrated, and its maximum flow was found to be 10.6 L/min. IOM samplers were placed on a mannequin, and sampling was conducted in a large aerosol wind tunnel at wind speeds of 0.56 and 2.22 m/s. Monodisperse aerosols of oleic acid tagged with sodium fluorescein in the size range of 2 to 100 microm were used in the test. The IOM samplers were operated at flow rates of 2.0 and 10.6 L/min. Results showed that the IOM samplers mounted in the front of the mannequin had a higher sampling efficiency than those mounted at the side and back, regardless of the wind speed and flow rate. For the wind speed of 0.56 m/s, the direction-averaged (the average value of all orientations facing the wind direction) sampling efficiency of the samplers operated at 2.0 L/min was slightly higher than that of 10.6 L/min. For the wind speed of 2.22 m/s, the sampling efficiencies at both flow rates were similar for particles < 60 microm. The results also show that the IOM's sampling efficiency at these two different flow rates follows the inhalable mass curve for particles in the size range of 2 to 20 microm. The test results indicate that the IOM sampler can be used at higher flow rates. PMID:19953412

  16. Studies on pressure losses and flow rate optimization in vanadium redox flow battery

    NASA Astrophysics Data System (ADS)

    Tang, Ao; Bao, Jie; Skyllas-Kazacos, Maria

    2014-02-01

    Premature voltage cut-off in the operation of the vanadium redox flow battery is largely associated with the rise in concentration overpotential at high state-of-charge (SOC) or state-of-discharge (SOD). The use of high constant volumetric flow rate will reduce concentration overpotential, although potentially at the cost of consuming excessive pumping energy which in turn lowers system efficiency. On the other hand, any improper reduction in flow rate will also limit the operating SOC and lead to deterioration in battery efficiency. Pressure drop losses are further exacerbated by the need to reduce shunt currents in flow battery stacks that requires the use of long, narrow channels and manifolds. In this paper, the concentration overpotential is modelled as a function of flow rate in an effort to determine an appropriate variable flow rate that can yield high system efficiency, along with the analysis of pressure losses and total pumping energy. Simulation results for a 40-cell stack under pre-set voltage cut-off limits have shown that variable flow rates are superior to constant flow rates for the given system design and the use of a flow factor of 7.5 with respect to the theoretical flow rate can reach overall high system efficiencies for different charge-discharge operations.

  17. Influence of Nitrogen Gas Flow Rate on the Electrical Behavior of an Atmospheric Pressure Dielectric Barrier Jet Discharge

    SciTech Connect

    Choo, C. Y.; Chin, O. H.

    2011-03-30

    The dielectric barrier discharge configuration used consists of a hemispherical electrode insulated by 1 mm thick borosilicate glass and a grounded plate with a hole through which the jet is formed externally in the surrounding air. The effect of gas flow rate on the behavior of an atmospheric pressure dielectric barrier jet discharge was studied for different air-gap distance and drive voltage, V{sub DD}, to the MOSFET. It is found that at higher rate of nitrogen gas flow, the current spikes reduce in number when the driving voltage and air-gap distance are kept constant.

  18. Flow visualization study of grooved surface/surfactant/air sheet interaction

    NASA Astrophysics Data System (ADS)

    Reed, Jason C.; Weinstein, Leonard M.

    1989-03-01

    The effects of groove geometry, surfactants, and airflow rate have been ascertained by a flow-visualization study of grooved-surface models which addresses the possible conditions for skin friction-reduction in marine vehicles. It is found that the grooved surface geometry holds the injected bubble stream near the wall and, in some cases, results in a 'tube' of air which remains attached to the wall. It is noted that groove dimension and the use of surfactants can substantially affect the stability of this air tube; deeper grooves, surfactants with high contact angles, and angled air injection, are all found to increase the stability of the attached air tube, while convected disturbances and high shear increase interfacial instability.

  19. Flow visualization study of grooved surface/surfactant/air sheet interaction

    NASA Technical Reports Server (NTRS)

    Reed, Jason C.; Weinstein, Leonard M.

    1989-01-01

    The effects of groove geometry, surfactants, and airflow rate have been ascertained by a flow-visualization study of grooved-surface models which addresses the possible conditions for skin friction-reduction in marine vehicles. It is found that the grooved surface geometry holds the injected bubble stream near the wall and, in some cases, results in a 'tube' of air which remains attached to the wall. It is noted that groove dimension and the use of surfactants can substantially affect the stability of this air tube; deeper grooves, surfactants with high contact angles, and angled air injection, are all found to increase the stability of the attached air tube, while convected disturbances and high shear increase interfacial instability.

  20. Effect of the Entrapped air on Water Flow in Heterogeneous Soil: Experimental Set- up

    NASA Astrophysics Data System (ADS)

    Snehota, M.; Sobotkova, M.; Cislerova, M.

    2008-12-01

    Temporal variations of steady state water flow rates were observed in laboratory infiltration experiments done on a sample of compacted sand and on an undisturbed soil sample (Eutric Cambisol). These variations are found to be in relation with entrapped air content. Infiltration-outflow experiments consisted of a series of ponded infiltration runs with seepage face boundary condition at the lower end of columns. The amount of the entrapped was derived from continuous weighing of the sample. The initial water contents were different for each run, which led to different amount of the air trapped in the soil during the first stages of infiltrations. The results of the experiments done on undisturbed soil showed that the flux rates and water contents varied during quasi-steady state. This finding contradicts the standard theory. The fluctuations of the water content during the steady state flow can be ascribed to the variations in volume of the entrapped air. Similarly, shape of the bromide breakthrough curve, which were performed simultaneously during the quasi-steady state varied for undisturbed soil. The same behaviour was not observed in the sample of homogeneous sand. Computer tomography was used to characterize the structure of the undisturbed soil sample with focus on potential preferential flow pathways, which are likely to host the entrapped air. To formulate more general conclusions, an extended series of infiltration outflow and bromide breakthrough experiments is in progress. This research has been supported by research project GACR 103/08/1552 and MSMT CEZ MSM 6840770002.

  1. SIMPLIFIED MODELING OF AIR FLOW DYNAMICS IN SSD RADON MITIGATION SYSTEMS FOR RESIDENCES WITH GRAVEL BEDS

    EPA Science Inventory

    In an attempt to better understand the dynamics of subslab air flow, the report suggests that subslab air flow induced by a central suction point be treated as radial air flow through a porous bed contained between two impermeable disks. (NOTE: Many subslab depressurization syste...

  2. 30 CFR 75.152 - Tests of air flow; qualified person.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tests of air flow; qualified person. 75.152....152 Tests of air flow; qualified person. A person is a qualified person within the meaning of the provisions of Subpart D—Ventilation of this part requiring that tests of air flow be made by a...

  3. Effects of flow rate and temperature on cyclic gas exchange in tsetse flies (Diptera, Glossinidae).

    PubMed

    Terblanche, John S; Chown, Steven L

    2010-05-01

    Air flow rates may confound the investigation and classification of insect gas exchange patterns. Here we report the effects of flow rates (50, 100, 200, 400 ml min(-1)) on gas exchange patterns in wild-caught Glossina morsitans morsitans from Zambia. At rest, G. m. morsitans generally showed continuous or cyclic gas exchange (CGE) but no evidence of discontinuous gas exchange (DGE). Flow rates had little influence on the ability to detect CGE in tsetse, at least in the present experimental setup and under these laboratory conditions. Importantly, faster flow rates resulted in similar gas exchange patterns to those identified at lower flower rates suggesting that G. m. morsitans did not show DGE which had been incorrectly identified as CGE at lower flow rates. While CGE cycle frequency was significantly different among the four flow rates (p<0.05), the direction of effects was inconsistent. Indeed, inter-individual variation in CGE cycle frequency exceeded flow rate treatment variation. Using a laboratory colony of closely related, similar-sized G. morsitans centralis we subsequently investigated the effects of temperature, gender and feeding status on CGE pattern variation since these factors can influence insect metabolic rates. At 100 ml min(-1) CGE was typical of G. m. centralis at rest, although it was significantly more common in females than in males (57% vs. 43% of 14 individuals tested per gender). In either sex, temperature (20, 24, 28 and 32 degrees C) had little influence on the number of individuals showing CGE. However, increases in metabolic rate with temperature were modulated largely by increases in burst volume and cycle frequency. This is unusual among insects showing CGE or DGE patterns because increases in metabolic rate are usually modulated by increases in frequency, but either no change or a decline in burst volume. PMID:20399350

  4. Mass flow rate measurement in abrasive jets using acoustic emission

    NASA Astrophysics Data System (ADS)

    Ivantsiv, V.; Spelt, J. K.; Papini, M.

    2009-09-01

    The repeatability of abrasive jet machining operations is presently limited by fluctuations in the mass flow rate due to powder compaction, stratification and humidity effects. It was found that the abrasive mass flow rate for a typical abrasive jet micromachining setup could be determined by using data from the acoustic emission of the abrasive jet impacting a flat plate. Two methods for extracting the mass flow rate from the acoustic emission were developed and compared. In the first method, the number of particle impacts per unit time was determined by a direct count of peaks in the acoustic emission signal. The second method utilizes the power spectrum density of the acoustic emission in a specific frequency range. Both measures were found to correlate strongly with the mass flow rate measured by weighing samples of blasted powder for controlled time periods. It was found that the peak count method permits measurement of the average frequency of the impacts and the mass flow rate, but can only be applied to flow rates in which the impact frequency is approximately one order of magnitude less than the frequency of the target plate ringing. The power spectrum density method of signal processing is applicable to relatively fine powders and to flow rates at which the average impact frequency is of the same order of magnitude as that of the ringing due to the impact. The acoustic emission technique can be used to monitor particle flow variations over a wide range of time periods and provides a straightforward and accurate means of process control.

  5. Air exchange rates from atmospheric CO2 daily cycle

    PubMed Central

    Carrilho, João Dias; Mateus, Mário; Batterman, Stuart; da Silva, Manuel Gameiro

    2015-01-01

    We propose a new approach for measuring ventilation air exchange rates (AERs). The method belongs to the class of tracer gas techniques, but is formulated in the light of systems theory and signal processing. Unlike conventional CO2 based methods that assume the outdoor ambient CO2 concentration is constant, the proposed method recognizes that photosynthesis and respiration cycle of plants and processes associated with fuel combustion produce daily, quasi-periodic, variations in the ambient CO2 concentrations. These daily variations, which are within the detection range of existing monitoring equipment, are utilized for estimating ventilation rates without the need of a source of CO2 in the building. Using a naturally-ventilated residential apartment, AERs obtained using the new method compared favorably (within 10%) to those obtained using the conventional CO2 decay fitting technique. The new method has the advantages that no tracer gas injection is needed, and high time resolution results are obtained. PMID:26236090

  6. Estimating rates of debris flow entrainment from ground vibrations

    NASA Astrophysics Data System (ADS)

    Kean, J. W.; Coe, J. A.; Coviello, V.; Smith, J. B.; McCoy, S. W.; Arattano, M.

    2015-08-01

    Debris flows generate seismic waves as they travel downslope and can become more dangerous as they entrain sediment along their path. We present field observations that show a systematic relation between the magnitude of seismic waves and the amount of erodible sediment beneath the flow. Specifically, we observe that a debris flow traveling along a channel filled initially with sediment 0.34 m thick generates about 2 orders of magnitude less spectral power than a similar-sized flow over the same channel without sediment fill. We adapt a model from fluvial seismology to explain this observation and then invert it to estimate the level of bed sediment (and rate of entrainment) beneath a passing series of surges. Our estimates compare favorably with previous direct measurements of entrainment rates at the site, suggesting the approach may be a new indirect way to obtain rare field constraints needed to test models of debris flow entrainment.

  7. Quartz Measurement in Coal Dust with High-Flow Rate Samplers: Laboratory Study

    PubMed Central

    LEE, TAEKHEE; LEE, EUN GYUNG; KIM, SEUNG WON; CHISHOLM, WILLIAM P.; KASHON, MICHAEL; HARPER, MARTIN

    2015-01-01

    A laboratory study was performed to measure quartz in coal dust using high-flow rate samplers (CIP10-R, GK2.69 cyclone, and FSP10 cyclone) and low-flow rate samplers [10-mm nylon and Higgins–Dewell type (BGI4L) cyclones] and to determine whether an increased mass collection from high-flow rate samplers would affect the subsequent quartz measurement by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analytical procedures. Two different sizes of coal dusts, mass median aerodynamic diameter 4.48 μm (Coal Dust A) and 2.33 μm (Coal Dust B), were aerosolized in a calm air chamber. The mass of coal dust collected by the samplers was measured gravimetrically, while the mass of quartz collected by the samplers was determined by FTIR (NIOSH Manual of Analytical Method 7603) and XRD (NIOSH Manual of Analytical Method 7500) after one of two different indirect preparations. Comparisons between high-flow rate samplers and low-flow rate samplers were made by calculating mass concentration ratios of coal dusts, net mass ratios of coal dusts, and quartz net mass. Mass concentrations of coal dust from the FSP10 cyclone were significantly higher than those from other samplers and mass concentrations of coal dust from 10-mm nylon cyclone were significantly lower than those from other samplers, while the CIP10-R, GK2.69, and BGI4L samplers did not show significant difference in the comparison of mass concentration of coal dusts. The BGI4L cyclone showed larger mass concentration of ~9% compared to the 10-mm nylon cyclone. All cyclones provided dust mass concentrations that can be used in complying with the International Standard Organization standard for the determination of respirable dust concentration. The amount of coal dust collected from the high-flow rate samplers was found to be higher with a factor of 2–8 compared to the low-flow rate samplers but not in direct proportion of increased flow rates. The high-flow rate samplers collected more quartz compared to

  8. Flow rate limitation in open wedge channel under microgravity

    NASA Astrophysics Data System (ADS)

    Wei, YueXing; Chen, XiaoQian; Huang, YiYong

    2013-08-01

    A study of flow rate limitation in an open wedge channel is reported in this paper. Under microgravity condition, the flow is controlled by the convection and the viscosity in the channel as well as the curvature of the liquid free surface. A maximum flow rate is achieved when the curvature cannot balance the pressure difference leading to a collapse of the free surface. A 1-dimensional theoretical model is used to predict the critical flow rate and calculate the shape of the free surface. Computational Fluid Dynamics tool is also used to simulate the phenomenon. Results show that the 1-dimensional model overestimates the critical flow rate because extra pressure loss is not included in the governing equation. Good agreement is found in 3-dimensional simulation results. Parametric study with different wedge angles and channel lengths show that the critical flow rate increases with increasing the cross section area; and decreases with increasing the channel length. The work in this paper can help understand the surface collapsing without gravity and for the design in propellant management devices in satellite tanks.

  9. Measuring OutdoorAir Intake Rates Using Electronic Velocity Sensors at Louvers and Downstream of Airflow Straighteners

    SciTech Connect

    Fisk, William; Sullivan, Douglas; Cohen, Sebastian; Han, Hwataik

    2008-10-01

    Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two new measurement approaches. Laboratory experiments determined that OA flow rates were measurable with errors generally less than 10percent using electronic air velocity probes installed between OA intake louver blades or at the outlet face of louvers. High accuracy was maintained with OA flow rates as low as 15percent of the maximum for the louvers. Thus, with this measurement approach HVAC systems do not need separate OA intakes for minimum OA supply. System calibration parameters are required for each unique combination of louver type and velocity sensor location but calibrations are not necessary for each system installation. The research also determined that the accuracy of measuring OA flow rates with velocity probes located in the duct downstream of the intake louver was not improved by installing honeycomb airflow straighteners upstream of the probes. Errors varied with type of upstream louver, were as high as 100percent, and were often greater than 25percent. In conclusion, use of electronic air velocity probes between the blades of OA intake louvers or at the outlet face of louvers is a highly promising means of accurately measuring rates of OA flow into HVAC systems. The use of electronic velocity probes downstream of airflow straighteners is less promising, at least with the relatively small OA HVAC inlet systems employed in this research.

  10. Rate-based ABR flow control using two timescale SPSA

    NASA Astrophysics Data System (ADS)

    Bhatnagar, Shalabh; Fu, Michael C.; Marcus, Steven I.

    1999-08-01

    In this paper, a two timescale simultaneous perturbation stochastic approximation algorithm is developed and applied to closed loop rate based available bit rate flow control. The relevant convergence results are stated and explained. Numerical experiments demonstrate fast convergence even in the presence of significant delays and a large number of parameterized policy levels.

  11. Granular flow through an aperture: pressure and flow rate are independent.

    PubMed

    Aguirre, María Alejandra; Grande, Juan Gabriel; Calvo, Adriana; Pugnaloni, Luis A; Géminard, Jean-Christophe

    2011-06-01

    We simultaneously measure the flow rate and the normal force on the base, near the outlet, during the discharge through an orifice of a dense packing of monosized disks driven by a conveyor belt. We find that the normal force on the base decreases even when a constant flow rate is measured. In addition, we show, by changing the mass of the disks, that pressure can be changed while the flow rate remains constant. Conversely, we are able, by changing the belt velocity, to set different flow rates for the same pressure. The experiment confirms that, contrary to what has been implicitly assumed in numerous works, the flow rate through an aperture is not controlled by the pressure in the outlet region. PMID:21797356

  12. MASS ACCRETION RATE OF ROTATING VISCOUS ACCRETION FLOW

    SciTech Connect

    Park, Myeong-Gu

    2009-11-20

    The mass accretion rate of transonic spherical accretion flow onto compact objects such as black holes is known as the Bondi accretion rate, which is determined only by the density and the temperature of gas at the outer boundary. A rotating accretion flow has angular momentum, which modifies the flow profile from the spherical Bondi flow, and hence its mass accretion rate, but most work on disc accretion has taken the mass flux to be given with the relation between that parameter and external conditions left uncertain. Within the framework of a slim alpha disk, we have constructed global solutions of the rotating, viscous, hot accretion flow in the Paczynski-Wiita potential and determined its mass accretion rate as a function of density, temperature, and angular momentum of gas at the outer boundary. We find that the low angular momentum flow resembles the spherical Bondi flow and its mass accretion rate approaches the Bondi accretion rate for the same density and temperature at the outer boundary. The high angular momentum flow on the other hand is the conventional hot accretion disk with advection, but its mass accretion rate can be significantly smaller than the Bondi accretion rate with the same boundary conditions. We also find that solutions exist only within a limited range of dimensionless mass accretion rate m-dotident toM-dot/M-dot{sub B}, where M-dot is the mass accretion rate and M-dot{sub B} is the Bondi accretion rate: when the temperature at the outer boundary is equal to the virial temperature, solutions exist only for 0.05approxrate is roughly independent of the radius of the outer boundary but inversely proportional to the angular momentum at the outer boundary and proportional to the viscosity parameter, m-dotapprox =9.0 alphalambda{sup -1} when 0.1 approx

  13. Optical observation of ultrafine droplets and air flows from newly designed supersonic air assist spray nozzles

    NASA Astrophysics Data System (ADS)

    Miyashiro, Seiji S.; Mori, H.; Takechi, H.

    2001-04-01

    One of the authors developed a new spray drying nozzle (special quadruplet fluid spray nozzle) for drug manufacturing and it has succeeded in manufacturing fine particles of 2 micrometer diameter of 1/15 ratios to those currently in use. The flow visualization results show that the two air jets become under-expanded on both edge sides of the nozzle, generate shock and expansion waves alternately on each side and reach the edge tip, where they collide, unite, and spout out while shock and expansion waves are again formed in the mixed jet. When the edge surfaces are supplied with water, the water is extended into thin film by the air jet and intensely disturbed. At the nozzle tip it is torn into droplets, which are further atomized afterwards in shock waves. At the spray tip, the friction with ambient air shears the droplets furthermore, and they decrease further in size.

  14. Non-equilibrium Flows of Reacting Air Components in Nozzles

    NASA Astrophysics Data System (ADS)

    Bazilevich, S. S.; Sinitsyn, K. A.; Nagnibeda, E. A.

    2008-12-01

    The paper presents the results of the investigation of non-equilibrium flows of reacting air mixtures in nozzles. State-to-state approach based on the solution of the equations for vibrational level populations of molecules and atomic concentrations coupled to the gas dynamics equations is used. For the 5-component air mixture (N2, O2, NO, N, O) non-equilibrium distributions and gasdynamical parameters are calculated for different conditions in a nozzle throat. The influence of various kinetic processes on distributions and gas dynamics parameters is studied. The paper presents the comparison of the results with ones obtained for binary mixtures of molecules and atoms and various models of elementary processes.

  15. Thermal characteristics of air flow cooling in the lithium ion batteries experimental chamber

    SciTech Connect

    Lukhanin A.; Rohatgi U.; Belyaev, A.; Fedorchenko, D.; Khazhmuradov, M.; Lukhanin, O; Rudychev, I.

    2012-07-08

    A battery pack prototype has been designed and built to evaluate various air cooling concepts for the thermal management of Li-ion batteries. The heat generation from the Li-Ion batteries was simulated with electrical heat generation devices with the same dimensions as the Li-Ion battery (200 mm x 150 mm x 12 mm). Each battery simulator generates up to 15W of heat. There are 20 temperature probes placed uniformly on the surface of the battery simulator, which can measure temperatures in the range from -40 C to +120 C. The prototype for the pack has up to 100 battery simulators and temperature probes are recorder using a PC based DAQ system. We can measure the average surface temperature of the simulator, temperature distribution on each surface and temperature distributions in the pack. The pack which holds the battery simulators is built as a crate, with adjustable gap (varies from 2mm to 5mm) between the simulators for air flow channel studies. The total system flow rate and the inlet flow temperature are controlled during the test. The cooling channel with various heat transfer enhancing devices can be installed between the simulators to investigate the cooling performance. The prototype was designed to configure the number of cooling channels from one to hundred Li-ion battery simulators. The pack is thermally isolated which prevents heat transfer from the pack to the surroundings. The flow device can provide the air flow rate in the gap of up to 5m/s velocity and air temperature in the range from -30 C to +50 C. Test results are compared with computational modeling of the test configurations. The present test set up will be used for future tests for developing and validating new cooling concepts such as surface conditions or heat pipes.

  16. Induction and measurement of minute flow rates through nanopipes

    NASA Astrophysics Data System (ADS)

    Sinha, Shashank; Pia Rossi, Maria; Mattia, D.; Gogotsi, Yury; Bau, Haim H.

    2007-01-01

    A simple technique to simultaneously induce fluid flow through an individual nanopipe and measure the flow rate and the pressure difference across the pipe is described. Two liquid drops of different sizes are positioned at the two ends of the nanopipe. Due to the higher capillary pressure of the smaller drop, flow is driven from the smaller drop to the bigger drop. The instantaneous pressures of the two drops are estimated from the drops' shapes and sizes. The flow rate is estimated by monitoring the sizes of the drops as functions of time with a microscope and a video camera. A theory that correlates the drops' sizes and the flow rate is derived. Measurements are carried out with an ionic salt and glycerin to estimate the effective tube radius of the nanopipes with diameters ranging from 200 to 300nm. The tubes' diameters are independently measured with a scanning electron microscope. The method is also verified by tracking the motion of fluorescent particles through the nanopipe. The paper provides a simple technique for studying extremely low flow rates in nanofluidic systems. When working with low-evaporation fluids such as ionic salts, the measurements can be carried out with an electron microscope.

  17. Onsite survey on the mechanism of passive aeration and air flow path in a semi-aerobic landfill.

    PubMed

    Matsuto, Toshihiko; Zhang, Xin; Matsuo, Takayuki; Yamada, Shuhei

    2015-02-01

    The semi-aerobic landfill is a widely accepted landfill concept in Japan because it promotes stabilization of leachates and waste via passive aeration without using any type of mechanical equipment. Ambient air is thought to be supplied to the landfill through a perforated pipe network made of leachate collection pipe laid along the bottom and a vertically erected gas vent. However, its underlying air flow path and driving forces are unclear because empirical data from real-world landfills is inadequate. The objective of this study is to establish scientific evidence about the aeration mechanisms and air flow path by an on-site survey of a full-scale, semi-aerobic landfill. First, all passive vents located in the landfill were monitored with respect to temperature level and gas velocity in different seasons. We found a linear correlation between the outflow rate and gas temperature, suggesting that air flow is driven by a buoyancy force caused by the temperature difference between waste in the landfill and the ambient temperature. Some vents located near the landfill bottom acted as air inflow vents. Second, we conducted a tracer test to determine the air flow path between two vents, by injecting tracer gas from an air sucking vent. The resulting slowly increasing gas concentration at the neighboring vent suggested that fresh air flow passes through the waste layer toward the gas vents from leachate collection pipes, as well as directly flowing through the pipe network. Third, we monitored the temperature of gas flowing out of a vent at night. Since the temperature drop of the gas was much smaller than that of the environment, the air collected at the gas vents was estimated to flow mostly through the waste layer, i.e., the semi-aerobic landfill has considerable aeration ability under the appropriate conditions. PMID:25443098

  18. Flow Analysis over Batten Reinforced Wings for Micro Air Vehicles

    NASA Astrophysics Data System (ADS)

    Townsend, Kurtis; Hicks, Travis; Hubner, James P.

    2008-11-01

    Flexible membrane wings modify the flow separation of low Reynolds number micro air vehicles (MAVs). A specific type of fixed-wing geometry is a batten-reinforced configuration in which the membrane is attached to a rigid frame with chordwise battens, allowing the vibration of the membrane at the trailing-edge. In this study, smoke-wire visualization and hot-wire anemometry, both near the trailing-edge and further downstream in the wake, are used to quantify the frequency and energy of these fluctuations for various cell geometries and flow angles-of-attack. Improvement in the wake momentum deficit will be analyzed to determine preferred membrane cell geometries for MAV flight conditions.

  19. Liquid Steel at Low Pressure: Experimental Investigation of a Downward Water Air Flow

    NASA Astrophysics Data System (ADS)

    Thumfart, Maria

    2016-07-01

    In the continuous casting of steel controlling the steel flow rate to the mould is critical because a well-defined flow field at the mould level is essential for a good quality of the cast product. The stopper rod is a commonly used device to control this flow rate. Agglomeration of solid material near the stopper rod can lead to a reduced cross section and thus to a decreased casting speed or even total blockage (“clogging”). The mechanisms causing clogging are still not fully understood. Single phase considerations of the flow in the region of the stopper rod result in a low or even negative pressure at the smallest cross section. This can cause degassing of dissolved gases from the melt, evaporation of alloys and entrainment of air through the porous refractory material. It can be shown that the degassing process in liquid steel is taking place mainly at the stopper rod tip and its surrounding. The steel flow around the stopper rod tip is highly turbulent. In addition refractory material has a low wettability to liquid steel. So the first step to understand the flow situation and transport phenomena which occur near the stopper is to understand the behaviour of this two phase (steel, gas) flow. To simulate the flow situation near the stopper rod tip, water experiments are conducted using a convergent divergent nozzle with three different wall materials and three different contact angles respectively. These experiments show the high impact of the wettability of the wall material on the actual flow structure at a constant gas flow rate.

  20. Laboratory Evaluation of Air Flow Measurement Methods for Residential HVAC Returns

    SciTech Connect

    Walker, Iain; Stratton, Chris

    2015-07-01

    This project improved the accuracy of air flow measurements used in commissioning California heating and air conditioning systems in Title 24 (Building and Appliance Efficiency Standards), thereby improving system performance and efficiency of California residences. The research team at Lawrence Berkeley National Laboratory addressed the issue that typical tools used by contractors in the field to test air flows may not be accurate enough to measure return flows used in Title 24 applications. The team developed guidance on performance of current diagnostics as well as a draft test method for use in future evaluations. The series of tests performed measured air flow using a range of techniques and devices. The measured air flows were compared to reference air flow measurements using inline air flow meters built into the test apparatus. The experimental results showed that some devices had reasonable results (typical errors of 5 percent or less) but others had much bigger errors (up to 25 percent).

  1. Upper air teleconnections to Ob River flows and tree rings

    NASA Astrophysics Data System (ADS)

    Meko, David; Panyushkina, Irina; Agafonov, Leonid

    2015-04-01

    The Ob River, one of the world's greatest rivers, with a catchment basin about the size of Western Europe, contributes 12% or more of the annual freshwater inflow to the Arctic Ocean. The input of heat and fresh water is important to the global climate system through effects on sea ice, salinity, and the thermohaline circulation of the ocean. As part of a tree-ring project to obtain multi-century long information on variability of Ob River flows, a network of 18 sites of Pinus, Larix, Populus and Salix has been collected along the Ob in the summers of 2013 and 2014. Analysis of collections processed so far indicates a significant relationship of tree-growth to river discharge. Moderation of the floodplain air temperature regime by flooding appears to be an important driver of the tree-ring response. In unraveling the relationship of tree-growth to river flows, it is important to identify atmospheric circulation features directly linked to observed time series variations of flow and tree growth. In this study we examine statistical links between primary teleconnection modes of Northern Hemisphere upper-air (500 mb) circulation, Ob River flow, and tree-ring chronologies. Annual discharge at the mouth of the Ob River is found to be significantly positively related to the phase of the East Atlantic (EA) pattern, the second prominent mode of low-frequency variability over the North Atlantic. The EA pattern, consisting of a north-south dipole of pressure-anomaly centers spanning the North Atlantic from east to west, is associated with a low-pressure anomaly centered over the Ob River Basin, and with a pattern of positive precipitation anomaly of the same region. The positive correlation of discharge and EA is consistent with these know patterns, and is contrasted with generally negative (though smaller) correlations between EA and tree-ring chronologies. The signs of correlations are consistent with a conceptual model of river influence on tree growth through air

  2. Simulation Analysis of Air Flow and Turbulence Statistics in a Rib Grit Roughened Duct

    PubMed Central

    Vogiatzis, I. I.; Denizopoulou, A. C.; Ntinas, G. K.; Fragos, V. P.

    2014-01-01

    The implementation of variable artificial roughness patterns on a surface is an effective technique to enhance the rate of heat transfer to fluid flow in the ducts of solar air heaters. Different geometries of roughness elements investigated have demonstrated the pivotal role that vortices and associated turbulence have on the heat transfer characteristics of solar air heater ducts by increasing the convective heat transfer coefficient. In this paper we investigate the two-dimensional, turbulent, unsteady flow around rectangular ribs of variable aspect ratios by directly solving the transient Navier-Stokes and continuity equations using the finite elements method. Flow characteristics and several aspects of turbulent flow are presented and discussed including velocity components and statistics of turbulence. The results reveal the impact that different rib lengths have on the computed mean quantities and turbulence statistics of the flow. The computed turbulence parameters show a clear tendency to diminish downstream with increasing rib length. Furthermore, the applied numerical method is capable of capturing small-scale flow structures resulting from the direct solution of Navier-Stokes and continuity equations. PMID:25057511

  3. Ozone concentrations in air flowing into New York State

    NASA Astrophysics Data System (ADS)

    Aleksic, Nenad; Kent, John; Walcek, Chris

    2016-09-01

    Ozone (O3) concentrations measured at Pinnacle State Park (PSPNY), very close to the southern border of New York State, are used to estimate concentrations in air flowing into New York. On 20% of the ozone season (April-September) afternoons from 2004 to 2015, mid-afternoon 500-m back trajectories calculated from PSPNY cross New York border from the south and spend less than three hours in New York State, in this area of negligible local pollution emissions. One-hour (2p.m.-3p.m.) O3 concentrations during these inflowing conditions were 46 ± 13 ppb, and ranged from a minimum of 15 ppb to a maximum of 84 ppb. On average during 2004-2015, each year experienced 11.8 days with inflowing 1-hr O3 concentrations exceeding 50 ppb, 4.3 days with O3 > 60 ppb, and 1.5 days had O3 > 70 ppb. During the same period, 8-hr average concentrations (10a.m. to 6p.m.) exceeded 50 ppb on 10.0 days per season, while 3.9 days exceeded 60 ppb, and 70 ppb was exceeded 1.2 days per season. Two afternoons of minimal in-state emission influences with high ozone concentrations were analyzed in more detail. Synoptic and back trajectory analysis, including comparison with upwind ozone concentrations, indicated that the two periods were characterized as photo-chemically aged air containing high inflowing O3 concentrations most likely heavily influenced by pollution emissions from states upwind of New York including Pennsylvania, Tennessee, West Virginia, and Ohio. These results suggest that New York state-level attempts to comply with National Ambient Air Quality Standards by regulating in-state O3 precursor NOx and organic emissions would be very difficult, since air frequently enters New York State very close to or in excess of Federal Air Quality Standards.

  4. Packet Scheduling Mechanism to Improve Quality of Short Flows and Low-Rate Flows

    NASA Astrophysics Data System (ADS)

    Yokota, Kenji; Asaka, Takuya; Takahashi, Tatsuro

    In recent years elephant flows are increasing by expansion of peer-to-peer (P2P) applications on the Internet. As a result, bandwidth is occupied by specific users triggering unfair resource allocation. The main packet-scheduling mechanism currently employed is first-in first-out (FIFO) where the available bandwidth of short flows is limited by elephant flows. Least attained service (LAS), which decides transfer priority of packets by the total amount of transferred data in all flows, was proposed to solve this problem. However, routers with LAS limit flows with large amount of transferred data even if they are low-rate. Therefore, it is necessary to improve the quality of low-rate flows with long holding times such as voice over Internet protocol (VoIP) applications. This paper proposes rate-based priority control (RBPC), which calculates the flow rate and control the priority by using it. Our proposed method can transfer short flows and low-rate flows in advance. Moreover, its fair performance is shown through simulations.

  5. Relativistic collision rate calculations for electron-air interactions

    SciTech Connect

    Graham, G.; Roussel-Dupre, R.

    1993-12-01

    The most recent data available on differential cross sections for electron-air interactions are used to calculate the avalanche, momentum transfer, and energy loss rates that enter into the fluid equations. Data for the important elastic, inelastic, and ionizing processes are generally available out to electron energies of 1--10 keV. Prescriptions for extending these cross sections to the relativistic regime are presented. The angular dependence of the cross sections is included where data are available as is the doubly differential cross section for ionizing collisions. The collision rates are computed by taking moments of the Boltzmann collision integrals with the assumption that the electron momentum distribution function is given by the Juettner distribution function which satisfies the relativistic H- theorem and which reduces to the familiar Maxwellian velocity distribution in the nonrelativistic regime. The distribution function is parameterized in terms of the electron density, mean momentum, and thermal energy and the rates are therefore computed on a two dimensional grid as a function of mean kinetic energy and thermal energy.

  6. Relativistic collision rate calculations for electron-air interactions

    SciTech Connect

    Graham, G.; Roussel-Dupre, R.

    1992-12-16

    The most recent data available on differential cross sections for electron-air interactions are used to calculate the avalanche, momentum transfer, and energy loss rates that enter into the fluid equations. Data for the important elastic, inelastic, and ionizing processes are generally available out to electron energies of 1--10 kev. Prescriptions for extending these cross sections to the relativistic regime are presented. The angular dependence of the cross sections is included where data is available as is the doubly differential cross section for ionizing collisions. The collision rates are computed by taking moments of the Boltzmann collision integrals with the assumption that the electron momentum distribution function is given by the Juettner distribution function which satisfies the relativistic H- theorem and which reduces to the familiar Maxwellian velocity distribution in the nonrelativistic regime. The distribution function is parameterized in terms of the electron density, mean momentum, and thermal energy and the rates are therefore computed on a two-dimensional grid as a function of mean kinetic energy and thermal energy.

  7. Heart-rate monitoring by air pressure and causal analysis

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Naoki; Nakajima, Hiroshi; Hata, Yutaka

    2011-06-01

    Among lots of vital signals, heart-rate (HR) is an important index for diagnose human's health condition. For instance, HR provides an early stage of cardiac disease, autonomic nerve behavior, and so forth. However, currently, HR is measured only in medical checkups and clinical diagnosis during the rested state by using electrocardiograph (ECG). Thus, some serious cardiac events in daily life could be lost. Therefore, a continuous HR monitoring during 24 hours is desired. Considering the use in daily life, the monitoring should be noninvasive and low intrusive. Thus, in this paper, an HR monitoring in sleep by using air pressure sensors is proposed. The HR monitoring is realized by employing the causal analysis among air pressure and HR. The causality is described by employing fuzzy logic. According to the experiment on 7 males at age 22-25 (23 on average), the correlation coefficient against ECG is 0.73-0.97 (0.85 on average). In addition, the cause-effect structure for HR monitoring is arranged by employing causal decomposition, and the arranged causality is applied to HR monitoring in a setting posture. According to the additional experiment on 6 males, the correlation coefficient is 0.66-0.86 (0.76 on average). Therefore, the proposed method is suggested to have enough accuracy and robustness for some daily use cases.

  8. Effect of viscoelasticity on the flow pattern and the volumetric flow rate in electroosmotic flows through a microchannel.

    PubMed

    Park, H M; Lee, W M

    2008-07-01

    Many lab-on-a-chip based microsystems process biofluids such as blood and DNA solutions. These fluids are viscoelastic and show extraordinary flow behaviors, not existing in Newtonian fluids. Adopting appropriate constitutive equations these exotic flow behaviors can be modeled and predicted reasonably using various numerical methods. In the present paper, we investigate viscoelastic electroosmotic flows through a rectangular straight microchannel with and without pressure gradient. It is shown that the volumetric flow rates of viscoelastic fluids are significantly different from those of Newtonian fluids under the same external electric field and pressure gradient. Moreover, when pressure gradient is imposed on the microchannel there appear appreciable secondary flows in the viscoelastic fluids, which is never possible for Newtonian laminar flows through straight microchannels. The retarded or enhanced volumetric flow rates and secondary flows affect dispersion of solutes in the microchannel nontrivially. PMID:18584093

  9. Effects of Mass Flow Rate on the Thermal-Flow Characteristics of Microwave CO2 Plasma.

    PubMed

    Hong, Chang-Ki; Na, Young-Ho; Uhm, Han-Sup; Kim, Youn-Jea

    2015-03-01

    In this study, the thermal-flow characteristics of atmospheric pressure microwave CO2 plasma were numerically investigated by simulation. The electric and gas flow fields in the reaction chamber with a microwave axial injection torch operated at 2.45 GHz were simulated. The microwave launcher had the standard rectangular waveguide WR340 geometry. The simulation was performed by using the COMSOL Multiphysics plasma model with various mass flow rates of CO2. The electric fields, temperature profiles and the density of electrons were graphically depicted for different CO2 inlet mass flow rates. PMID:26413663

  10. Comparison of saturation flow rates at signalized intersections

    SciTech Connect

    Stokes, R.W.

    1988-11-01

    The intersection, being the focal point of conflicts and congestion in the roadway network, is a critical area in the efficient use of the urban street system. As a result, the capacity of the intersection, particularly the signalized intersection, has been the subject of much research in recent years. Procedures for estimating signalized intersection capacity are typically based on the use of an ideal, maximum traffic flow rate (saturation flow) that is adjusted to reflect site-specific conditions that may not be ideal. Regardless of the specific procedure used in signalized intersection capacity analyses, saturates flow is used as the base flow rate. Various capacity influencing factors are then used to modify this base flow value to reflect prevailing conditions. This article presents a brief review of studied conducted to estimate saturation flows at signalized intersections. Given the sensitivity of signalized intersection capacity analysis procedures to saturation flow values, the information presented here should be of interest to the practitioner, as well as the theorist.