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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS2010

Preliminary Testing of a Pressurized Space Suit and Candidate Fabrics Under Simulated Mars Dust Storm and Dust Devil Conditions

In August 2009 YAP Films (Toronto) received permission from all entities involved to create a documentary film illustrating what it might be like to be on the surface of Mars in a space suit during a dust storm or in a dust devil. The science consultants on this project utilized this opportunity to collect data which could be helpful to assess the durability of current space suit construction to the Martian environment. The NDX?1 prototype planetary space suit developed at the University of North Dakota was used in this study. The suit features a hard upper torso garment, and a soft lower torso and boots assembly. On top of that, a nylon-cotton outer layer is used to protect the suit from dust. Unmanned tests were carried out in the Martian Surface Wind Tunnel (MARSWIT) at the NASA Ames Research Center, with the suit pressurized to 10 kPa gauge. These tests blasted the space suit upper torso and helmet, and a collection of nine candidate outer layer fabrics, with wind-borne simulant for five different 10 minute tests under both terrestrial and Martian surface pressures. The infiltration of the dust through the outer fabric of the space suit was photographically documented. The nine fabric samples were analyzed under light and electron microscopes for abrasion damage. Manned tests were carried out at Showbiz Studios (Van Nuys, CA) with the pressure maintained at 20?2 kPa gauge. A large fan-created vortex lifted Martian dust simulant (Fullers Earth or JSC Mars?1) off of the floor, and one of the authors (Lee) wearing the NDX?1 space suit walked through it to judge both subjectively and objectively how the suit performed under these conditions. Both the procedures to scale the tests to Martian conditions and the results of the infiltration and abrasion studies will be discussed.

Gaier, James R.↗
NASA NTRS2010

Preliminary Testing of a Pressurized Space Suit and Candidate Fabrics Under Simulated Mars Dust Storm and Dust Devil Conditions

In August 2009 YAP Films (Toronto) received permission from all entities involved to create a documentary film illustrating what it might be like to be on the surface of Mars in a space suit during a dust storm or in a dust devil. The science consultants on this project utilized this opportunity to collect data which could be helpful to assess the durability of current space suit construction to the Martian environment. The NDX-1 prototype planetary space suit developed at the University of North Dakota was used in this study. The suit features a hard upper torso garment, and a soft lower torso and boots assembly. On top of that, a nylon-cotton outer layer is used to protect the suit from dust. Unmanned tests were carried out in the Martian Surface Wind Tunnel (MARSWIT) at the NASA Ames Research Center, with the suit pressurized to 10 kPa gauge. These tests blasted the space suit upper torso and helmet, and a collection of nine candidate outer layer fabrics, with wind-borne simulant for five different 10 min tests under both terrestrial and Martian surface pressures. The infiltration of the dust through the outer fabric of the space suit was photographically documented. The nine fabric samples were analyzed under light and electron microscopes for abrasion damage. Manned tests were carried out at Showbiz Studios (Van Nuys, California) with the pressure maintained at 20 2 kPa gauge. A large fan-created vortex lifted Martian dust simulant (Fullers Earth or JSC Mars-1) off of the floor, and one of the authors (Lee) wearing the NDX-1 space suit walked through it to judge both subjectively and objectively how the suit performed under these conditions. Both the procedures to scale the tests to Martian conditions and the results of the infiltration and abrasion studies will be discussed.

Gaier, James R.↗
NASA NTRS1989

Teledyne Taber 206-1000 and 2210-3000 pressure transducer proof test and burst test

The range accuracy and structural integrity of the Teledyne Taber 206-1000 and 2210-3000 pressure transducers are verified and multiple uses are studied to determine is they have a significant effect on the transducers. Burst pressure for these transducers was also established. The Teledyne Taber 206-1000 pressure transducer is used to measure chamber pressure on full-scale space shuttle rocket motors. The Teledyne Taber 2210-3000 pressure transducer is used to measure igniter pressure. The Teledyne Taber transducer has very good temperature stability and was used on all full-scale solid rocket motors, so there is a large data base established using this transducer.

Ricks, G. A.↗
NASA NTRS1973

Creep-rupture tests of internally pressurized Hastelloy-X tubes

Seamless Hastelloy-X tubes with 0.375-in. outside diameter and 0.025-in. wall thickness were tested to failure at temperatures from 1400 to 1650 F and internal helium pressures from 800 to 1800 psi. Lifetimes ranged from 58 to 3600 hr. The creep-rupture strength of the tubes was from 20 to 40 percent lower than that of sheet specimens. Larson-Miller correlations and photomicrographs of some specimens are presented.

Gumto, K. H.↗
DOE OSTI2022

Leaf water potential measurements using the pressure chamber: Synthetic testing of assumptions towards best practices for precision and accuracy

Leaf water potential (ψ leaf ), typically measured using the pressure chamber, is the most important metric of plant water status, providing high theoretical value and information content for multiple applications in quantifying critical physiological processes including drought responses. Pressure chamber measurements of ψ leaf (ψ leafPC ) are most typical, yet, the practical complexity of the technique and of the underlying theory has led to ambiguous understanding of the conditions to optimize measurements. Consequently, specific techniques and precautions diversified across the global research community, raising questions of reliability and repeatability. Here, we surveyed specific methods of ψ leafPC from multiple laboratories, and synthesized experiments testing common assumptions and practices in ψ leafPC for diverse species: (i) the need for equilibration of previously transpiring leaves; (ii) leaf storage before measurement; (iii) the equilibration of ψ leaf for leaves on bagged branches of a range of dehydration; (iv) the equilibration of ψ leaf across the lamina for bagged leaves, and the accuracy of measuring leaves with artificially ‘elongated petioles’; (v) the need in ψ leaf measurements for bagging leaves and high humidity within the chamber; (vi) the need to avoid liquid water on leaf surfaces; (vii) the use of ‘pulse’ pressurization versus gradual pressurization; and (viii) variation among experimenters in ψ leafPC determination. Based on our findings we provide a best practice protocol to maximise accuracy, and provide recommendations for ongoing species-specific tests of important assumptions in future studies.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1992

Tests Of Array Of Flush Pressure Sensors

Report describes tests of array of pressure sensors connected to small orifices flush with surface of 1/7-scale model of F-14 airplane in wind tunnel. Part of effort to determine whether pressure parameters consisting of various sums, differences, and ratios of measured pressures used to compute accurately free-stream values of stagnation pressure, static pressure, angle of attack, angle of sideslip, and mach number. Such arrays of sensors and associated processing circuitry integrated into advanced aircraft as parts of flight-monitoring and -controlling systems.

Larson, Larry J.↗
NASA NTRS2011

Water Flow Testing and Unsteady Pressure Analysis of a Two-Bladed Liquid Oxidizer Pump Inducer

The unsteady fluid dynamic performance of a cavitating two-bladed oxidizer turbopump inducer was characterized through sub-scale water flow testing. While testing a novel inlet duct design that included a cavitation suppression groove, unusual high-frequency pressure oscillations were observed. With potential implications for inducer blade loads, these high-frequency components were analyzed extensively in order to understand their origins and impacts to blade loading. Water flow testing provides a technique to determine pump performance without the costs and hazards associated with handling cryogenic propellants. Water has a similar density and Reynolds number to liquid oxygen. In a 70%-scale water flow test, the inducer-only pump performance was evaluated. Over a range of flow rates, the pump inlet pressure was gradually reduced, causing the flow to cavitate near the pump inducer. A nominal, smooth inducer inlet was tested, followed by an inlet duct with a circumferential groove designed to suppress cavitation. A subsequent 52%-scale water flow test in another facility evaluated the combined inducer-impeller pump performance. With the nominal inlet design, the inducer showed traditional cavitation and surge characteristics. Significant bearing loads were created by large side loads on the inducer during synchronous cavitation. The grooved inlet successfully mitigated these loads by greatly reducing synchronous cavitation, however high-frequency pressure oscillations were observed over a range of frequencies. Analytical signal processing techniques showed these oscillations to be created by a rotating, multi-celled train of pressure pulses, and subsequent CFD analysis suggested that such pulses could be created by the interaction of rotating inducer blades with fluid trapped in a cavitation suppression groove. Despite their relatively low amplitude, these high-frequency pressure oscillations posed a design concern due to their sensitivity to flow conditions and test scale. The amplitude and frequency of oscillations varied considerably over the pump s operating space, making it difficult to predict blade loads.

Schwarz, Jordan B.↗
NASA NTRS1972

Creep-rupture tests of internally pressurized Rene 41 tubes

Weld-drawn tubes of Rene 41 with 0.935 centimeter outside diameter and 0.064 centimeter wall thickness were tested to failure at temperatures from 1117 to 1233 K and internal helium pressures from 5.5 to 12.4 meganewtons per square meter. Lifetimes ranged from 5 to 2065 hours. The creep-rupture strength of the tubes was 50 percent lower than that of unwelded, thick sheet specimens, and 20 percent lower than that of unwelded, thin sheet specimens. Larson-Miller correlations and photomicrographs of some specimens are presented.

Gumto, K. H.↗
NASA NTRS1972

Valve, normally open, titanium: Pyronetics Model 1425

An operating test series was applied to two explosive actuated, normally open, titanium valves. There were no failures. Tests included: proof pressure and external leakage test, gross leak test, post actuation leakage test, and burst pressure test.

Avalos, E.↗
NASA NTRS2012

Burning of CP Titanium (Grade 2) in Oxygen-Enriched Atmospheres

The flammability in oxygen-enriched atmospheres of commercially pure (CP) titanium rods as a function of diameter and test gas pressure was determined. Test samples of varying diameters were ignited at the bottom and burned upward in 70% O2/balance N2 and in 99.5+% O2 at various pressures. The burning rate of each ignited sample was determined by observing the apparent regression rate of the melting interface (RRMI) of the burning samples. The burning rate or RRMI increased with decreasing test sample diameter and with increasing test gas pressure and oxygen concentration

Stoltzfus, Joel M.↗
NASA NTRS1991

Pressure vessel burst test program. II

The current status is disucssed of a program to study the characteristics of blast waves and fragmentation generated by ruptured gas-filled pressure vessels. Current methods for assessing vessel safety and burst parameters are briefly reviewed, and pneumatic burst testing operations and testing results are examined. A comparison is made with current methods for burst assessment. It is tentatively concluded that, at close distances, vessel burst overpressures are less than those of high-explosive (HE) blasts with equivalent energy and are greater than HE far from the vessel. The impulse appears to be the same for both vessel bursts and equivalent energy HE blasts. The functional relationship between shock velocity and overpressure ratio appears to be the same for vessel bursts as for HE blasts. The initial shock overpressure appears to be much less than vessel pressure and may be found using the one-dimensional shock tube equation.

Cain, Maurice R.↗
NASA NTRS2015

Evolvable Cryogenics (ECRYO) Pressure Transducer Calibration Test

This paper provides a summary of the findings of recent activities conducted by Marshall Space Flight Center's (MSFC) In-Space Propulsion Branch and MSFC's Metrology and Calibration Lab to assess the performance of current "state of the art" pressure transducers for use in long duration storage and transfer of cryogenic propellants. A brief historical narrative in this paper describes the Evolvable Cryogenics program and the relevance of these activities to the program. This paper also provides a review of three separate test activities performed throughout this effort, including: (1) the calibration of several pressure transducer designs in a liquid nitrogen cryogenic environmental chamber, (2) the calibration of a pressure transducer in a liquid helium Dewar, and (3) the calibration of several pressure transducers at temperatures ranging from 20 to 70 degrees Kelvin (K) using a "cryostat" environmental chamber. These three separate test activities allowed for study of the sensors along a temperature range from 4 to 300 K. The combined data shows that both the slope and intercept of the sensor's calibration curve vary as a function of temperature. This homogeneous function is contrary to the linearly decreasing relationship assumed at the start of this investigation. Consequently, the data demonstrates the need for lookup tables to change the slope and intercept used by any data acquisition system. This ultimately would allow for more accurate pressure measurements at the desired temperature range. This paper concludes with a review of a request for information (RFI) survey conducted amongst different suppliers to determine the availability of current "state of the art" flight-qualified pressure transducers. The survey identifies requirements that are most difficult for the suppliers to meet, most notably the capability to validate the sensor's performance at temperatures below 70 K.

Diaz, Carlos E., Jr.↗
DOE OSTI2022

Laboratory and In-Pile Testing of a Fiber Optic Pressure Sensor

The development, testing and deployment of a fiber-optic-based extrinsic Fabry-Perot pressure sensor is discussed. The details of design and fabrication procedure is discussed and the methodology for design decisions is provided. Results from laboratory-based testing and calibration is provided as-well-as preliminary data from in-pile testing in the Transient Reactor Test Facility.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS2001

Numerical Modeling of Helium Pressurization System of Propulsion Test Article (PTA)

A transient model of the Propulsion Test Article (PTA) Helium Pressurization System was developed using the Generalized Fluid System Simulation Program (GFSSP). The model included feed lines from the facility interface to the engine purge interface and Liquid Oxygen (LOX) and Rocket Propellant 1 (RP-1) tanks, the propellant tanks themselves including ullage space and propellant feed lines to their respective pump interfaces. GFSSP's capability was extended to model a control valve to maintain ullage pressure within a specified limit and pressurization processes such as heat transfer between ullage gas, propellant and the tank wall. The purpose of the model is to predict the flow system characteristics in the entire pressurization system during 80 seconds of lower feed system priming, 420 seconds of fuel and LOX pump priming and 150 seconds of engine firing. Subsequent to the work presented here, the PTA model has been updated to include the LOX and RP-1 pumps, while the pressurization option itself has been modified to include the effects of mass transfer. This updated model will be compared with PTA test data as it becomes available.

Steadman, Todd↗
NASA NTRS1993

Pressure Vessel Burst Test Program - Progress paper No. 4

A status report is presented for a program studying the characteristics of the blast waves and fragmentation caused by ruptured gas-filled pressure vessels. Experimental data trends have been derived from 14 burst pressure vessels. Attention is given to energy release in bursting, blast wave and fragmentation behavior, height of burst effects, fragment velocity vs vessel pressure, and comparative blast effects for spherical/composite vs cylindrical/steel pressure vessels.

Maurice R Cain↗
NASA NTRS1979

Proof test criteria for thin walled pressure vessels

A proof test criterion for assuring minimum service life requirements for aerospace pressure vessels is provided. The criteria proposed are based on the results of several experimental programs conducted on surface flaw specimens fabricated from 2219 aluminum base and weld metal. A description is presented of the stable crack growth behavior of surface flaws during loading. Conclusions derived from an experimental program are discussed. It is found that significant stable crack growth under increasing load can occur prior to failure. However, significant variability in results can be anticipated even when carefully controlled laboratory procedures are employed.

Finger, R. W.↗