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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,351 records · Page 75
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Low subsonic aerodynamic characteristics of five irregular planform wings with systematically varying wing fillet geometry tested in the NASA/Ames 12 foot pressure tunnel (LA65)

An experimental and analytical aerodynamic program to develop predesign guides for irregular planform wings (also referred to as cranked leading edge or double delta wings is reported; the benefits are linearization of subsonic lift curve slope to high angles of attack and avoidance of subsonic pitch instabilities at high lift by proper tailoring of the planform-fillet-wing combination while providing the desired hypersonic trim angle and stability. Because subsonic and hypersonic conditions were the two prime areas of concern in the initial application of this program to optimize shuttle orbiter landing and entry characteristics, the study was designated the Subsonic/Hypersonic Irregular Planforms Study (SHIPS).

Ball, J. W.↗
NASA NTRS1982

Circumferential pressure distributions in a model labyrinth seal

A research program to isolate and study leakage flow through labyrinth glands was initiated. Circumferential pressure distributions were measured in the labyrinth glands with geometry appropriate to the high pressure labyrinths in large steam turbines. Knowledge of this pressure distribution is essential as it is this unequal pressure field that results in the destabilizing force. Parameters that are likely to affect the pressure distributions are incorporated into the test rig. Some preliminary pressure profiles are presented.

Leong, Y. M. M. S.↗
NASA NTRS1989

Study of the integration of wind tunnel and computational methods for aerodynamic configurations

A study was conducted to determine the effectiveness of using a low-order panel code to estimate wind tunnel wall corrections. The corrections were found by two computations. The first computation included the test model and the surrounding wind tunnel walls, while in the second computation the wind tunnel walls were removed. The difference between the force and moment coefficients obtained by comparing these two cases allowed the determination of the wall corrections. The technique was verified by matching the test-section, wall-pressure signature from a wind tunnel test with the signature predicted by the panel code. To prove the viability of the technique, two cases were considered. The first was a two-dimensional high-lift wing with a flap that was tested in the 7- by 10-foot wind tunnel at NASA Ames Research Center. The second was a 1/32-scale model of the F/A-18 aircraft which was tested in the low-speed wind tunnel at San Diego State University. The panel code used was PMARC (Panel Method Ames Research Center). Results of this study indicate that the proposed wind tunnel wall correction method is comparable to other methods and that it also inherently includes the corrections due to model blockage and wing lift.

Browne, Lindsey E.↗
NASA NTRS1989

Small Displacement, Long Life On-Orbit Compressor Design and Fabrication

The focus is the generation of technology and fabrication of prototype hardware applicable to seven Space Station compressor system applications. The compressors are of the single acting reciprocating piston type and, in general, may be termed miniature in size compared with normal commercially available equipment. The initial technology development is focused on improved valve designs, and the control of pulsations and heating effects in order to increase compressor efficiency and reduce cycle temperatures, thus permitting significantly increased stage pressure ratios. The initial test compressor was successfully operated at pressure ratios of up to 50:1, and this significant extension of allowable pressure ratio will result in a reduction of the number of required stages and, hence, total hardware thereby reducing system weight and volume. These experiments have also identified the need to employ low shaft speeds, on the order of 250 to 500 rpm, to enhance heat transfer and increase life. The prototype compressor currently being designed, is to be driven by a low-speed brushless dc motor sealed in a case common to the compressor drive mechanism case. The compressor and motor case will communicate with stage suction pressure so that any minor gas leakage past the piston rings will be returned to the suction. Emphasis in this prototype design is being placed on simplicity, durability, commonality of components, and high efficiency.

Gerlach, C. R.↗
NASA NTRS1998

Forced Convection Boiling and Critical Heat Flux of Ethanol in Electrically Heated Tube Tests

Electrically heated tube tests were conducted to characterize the critical heat flux (transition from nucleate to film boiling) of subcritical ethanol flowing at conditions relevant to the design of a regeneratively cooled rocket engine thrust chamber. The coolant was SDA-3C alcohol (95% ethyl alcohol, 5% isopropyl alcohol by weight), and tests were conducted over the following ranges of conditions: pressure from 144 to 703 psia, flow velocities from 9.7 to 77 ft/s, coolant subcooling from 33 to 362 F, and critical heat fluxes up to 8.7 BTU/in(exp 2)/sec. For the data taken near 200 psia, critical heat flux was correlated as a function of the product of velocity and fluid subcooling to within +/- 20%. For data taken at higher pressures, an additional pressure term is needed to correlate the critical heat flux. It was also shown that at the higher test pressures and/or flow rates, exceeding the critical heat flux did not result in wall burnout. This result may significantly increase the engine heat flux design envelope for higher pressure conditions.

Meyer, Michael L.↗
NASA NTRS2012

NASA Environmentally Responsible Aviation High Overall Pressure Ratio Compressor Research Pre-Test CFD

This paper describes a collaborative and cost-shared approach to reducing fuel burn under the NASA Environmentally Responsible Aviation project. NASA and General Electric (GE) Aviation are working together aa an integrated team to obtain compressor aerodynamic data that is mutually beneficial to both NASA and GE Aviation. The objective of the High OPR Compressor Task is to test a single stage then two stages of an advanced GE core compressor using state-of-the-art research instrumentation to investigate the loss mechanisms and interaction effects of embedded transonic highly-loaded compressor stages. This paper presents preliminary results from NASA's in-house multistage computational code, APNASA, in preparation for this advanced transonic compressor rig test.

Celestina, Mark L.↗
NASA NTRS2013

Estimating the Collapse Pressure of an Inflatable Aerodynamic Decelerator

The collapse pressure of an inflatable membrane is the minimum differential pressure which will sustain a specific desired shape under an applied load. In this paper, we present a method for estimating the collapse pressure of a tension-cone inflatable aerodynamic decelerator (IAD) that is subject to a static aerodynamic load. The IAD surface is modeled as an elastic membrane. For a given aerodynamic load and sufficiently high torus differential pressure, the IAD assumes a stable axisymmetric equilibrium shape. When the torus pressure is reduced sufficiently, the symmetric equilibrium state becomes unstable and we define this instance to be the critical pressure Pcr. In this paper, we will compare our predicted critical torus pressure with the corresponding observed torus collapse pressure (OTCP) for fifteen tests that were conducted by the third author and his collaborators at the NASA Glenn Research Center 10x10 Supersonic Wind Tunnel in April 2008. One of the difficulties with these types of comparisons is establishing the instance of torus collapse and determining the OTCP from quantities measured during the experiment. In many cases, torus collapse is gradual and the OTCP is not well-defined. However, in eight of the fifteen wind tunnel tests where the OTCP is well-defined, we find that the average of the relative differences (Pcr - OTCP/Pcr) was 8.9%. For completeness, we will also discuss the seven tests where the observed torus collapse pressure is not well-defined.

Baginski, Frank E.↗
NASA NTRS2017

Application of Background Oriented Schlieren for Altitude Testing of Rocket Engines

A series of experiments was performed to determine the feasibility of using the Background Oriented Schlieren, BOS, flow visualization technique to image a simulated, small, rocket engine, plume under altitude test conditions. Testing was performed at the NASA Glenn Research Centers Altitude Combustion Stand, ACS, using nitrogen as the exhaust gas simulant. Due to limited optical access to the facility test capsule, all of the hardware required to conduct the BOS were located inside the vacuum chamber. During the test series 26 runs were performed using two different nozzle configurations with pressures in the test capsule around 0.3 psia. No problems were encountered during the test series resulting from the optical hardware being located in the test capsule and acceptable resolution images were captured. The test campaign demonstrated the ability of using the BOS technique for small, rocket engine, plume flow visualization during altitude testing.

Background Oriented Schlieren↗
NASA NTRS2011

Small Scale Trace Contaminant Testing of SA9T at Ambient and Reduced Pressure Conditions

A principle concern for air revitalization technology in a closed loop system is the capability to control carbon dioxide (CO2) and humidity (H2O). An amine based sorbent technology, SA9T, has long been evaluated for use in this application and several programs are evaluating it for use in both a cabin as well as space suit applications. While the CO2 and H2O performance of the sorbent has been tested extensively, the question of how trace contaminants impact performance requires further evaluation. This paper presents experimental results of small scale SA9T testing that was performed over a variety of test conditions and with a variety of trace contaminants. Testing evaluated the ability of SA9T media to sufficiently remove CO2 and H2O after exposure to a fully saturated trace contaminant at ambient conditions. Testing also evaluated the impact of CO2 and H2O removal performance at suit loop pressures during cyclic operation with a constant inlet contaminant load. In addition, testing evaluated the performance of SA9T at ambient conditions in a continuous 30-day test with a mixed trace contaminant stream.

Broerman, Craig↗
DOE OSTI2019

LANL Phase 3 Test Plan For Container Loading to Support the Fire-Induced Pressure Response and Failure Characterization of PCV/SCV/3013 Containers

Fire testing of 3013 containers loaded with surrogate materials and water will be conducted to determine the response of 3013 containers stored in K-Area Complex (KAC) to a facility fire. Based on the proposal for the test configuration and loading, the objectives of the fire test are as follows: 1. “To increase understanding about the pressure and temperature conditions at which failure occurs; 2. To determine the allowable moisture for which failure will not occur under specified fire conditions, and 3. To increase understanding regarding the effects of salts on the pressurization, corrosion, and potential failure of the container.” Surrogate materials will be prepared at Los Alamos National Laboratory (LANL) and loaded in the 3013 containers. The containers will then be welded at LANL and shipped to Savannah River Site (SRS) for the installation of fittings and leak testing.

42 ENGINEERING↗
NASA NTRS1984

Experiences with a high-blockage model tested in the NASA Ames 12-foot pressure wind tunnel

Representation of the flow around full-scale ships was sought in the subsonic wind tunnels in order to a Hain Reynolds numbers as high as possible. As part of the quest to attain the largest possible Reynolds number, large models with high blockage are used which result in significant wall interference effects. Some experiences with such a high blockage model tested in the NASA Ames 12-foot pressure wind tunnel are summarized. The main results of the experiment relating to wind tunnel wall interference effects are also presented.

Coder, D. W.↗
NASA NTRSDate not supplied

Analysis of Dynamic Mode Decomposition Outputs of Unsteady Pressure-Sensitive Paint Measurements in the NASA Wind Tunnel Tests

This paper discusses the Dynamic Mode Decomposition (DMD) outputs of the Unsteady Pressure-Sensitive Paint (uPSP) measurements, which were collected with four Phantom high-speed cameras at a constant sample frequency in the Ascent Transient Aerodynamics Test (ATAT) of the Space Launch System (SLS) Block 1 cargo vehicle in the 11-by-11-foot transonic test section of the Unitary Plan Wind Tunnel (UPWT) at NASA Ames Research Center in September 2019. In this paper, the effectiveness to use the DMD outputs of uPSP measurements in the diagnosis and analysis of the aerodynamic and acoustic phenomena in the SLS ATAT is demonstrated. The work described in the paper is a part of NASA’s development of a new state-of-the-art uPSP capability in production wind tunnels. Funding was provided by the NASA Aerosciences Evaluation and Test Capabilities (AETC) Project.

acoustics↗
DOE OSTI2025

Durable, Ultra-Thin Diaphragms for Liquid Alkaline Water Electrolysis

W. L. Gore & Associates assembled a world class team (De Nora Tech, LLC; New York University; and thyssenkrupp nucera) to develop durable, ultra-low resistance diaphragms that dramatically improve system efficiency, dynamic response, and operational flexibility. To enable the use of ultra-thin diaphragms, an optimized electrode package was chosen as part of an electrode down select study. Ultra-thin diaphragms based on microporous polymer scaffolds imbibed with zirconia nanoparticles were developed and tested. Performance and durability on par with incumbent materials was demonstrated. A transparent electrolyzer to directly observe in-situ diaphragm-bubble interactions was designed and built, and simultaneous optical and electrochemical performance tests were performed. A Pressurized Alkaline Water Electrolysis (PAWE) single cell test station was designed to support advanced R&D in high-pressure electrolysis, particularly for evaluating novel electrode and separator configurations under elevated temperature and pressure operating conditions. Due to early project termination, the original scope could not be fully achieved.

08 HYDROGEN↗
NASA NTRS2012

Analysis of Screen Channel LAD Bubble Point Tests in Liquid Methane at Elevated Temperature

This paper examines the effect of varying the liquid temperature and pressure on the bubble point pressure for screen channel Liquid Acquisition Devices in cryogenic liquid methane using gaseous helium across a wide range of elevated pressures and temperatures. Testing of a 325 x 2300 Dutch Twill screen sample was conducted in the Cryogenic Components Lab 7 facility at the NASA Glenn Research Center in Cleveland, Ohio. Test conditions ranged from 105 to 160K and 0.0965 - 1.78 MPa. Bubble point is shown to be a strong function of the liquid temperature and a weak function of the amount of subcooling at the LAD screen. The model predicts well for saturated liquid but under predicts the subcooled data.

Hartwig, Jason↗
NASA NTRS1999

Physiologic Pressure and Flow Changes During Parabolic Flight (Pilot Study)

The objective of this study was to obtain measurement of cutaneous tissue perfusion central and peripheral venous pressure, and esophageal and abdominal pressure in human test subjects during parabolic flight. Hemodynamic data recorded during SLS-I and SLS-2 missions have resulted in the paradoxical finding of increased cardiac stroke volume in the presence of a decreased central venous pressure (CVP) following entry in weightlessness. The investigators have proposed that in the absence of gravity, acceleration-induced peripheral vascular compression is relieved, increasing peripheral vascular capacity and flow while reducing central and peripheral venous pressure, This pilot study seeks to measure blood pressure and flow in human test subjects during parabolic flight for different postures.

Pantalos, George↗
NASA NTRSDate not supplied

Development of Neural Network for X-59 Air Data Probe Calibration

Two wind tunnel tests were conducted in the NASA Glenn Research Center (GRC) 8- by 6-Foot Supersonic Wind Tunnel to calibrate the nose-mounted air data probe for the X-59. The probe will be the primary instrument for the flight test of the X-59 for determining angle of attack, angle of sideslip, airspeed, and pressure altitude of the aircraft in flight. This paper documents the development of several neural net algorithms that can be used to relate air data probe port pressures from those tests to relevant X-59 flight parameters, such as angle of attack, angle of sideslip, mach number, and static and dynamic pressure. These calibration algorithms address accuracy effects for significant real-world conditions, such as initial sensor measurement uncertainties, assumed parameter constraints on NN modelling errors, and malfunctioning or plugged ports. Resultant integrated uncertainties are provided for each algorithm; these uncertainties are then used to estimate the effects on relevant X-59 mission parameters.

Kurtis Roy Long↗