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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 NTRS1980

VCE early acoustic test results of General Electric's high-radius ratio coannular plug nozzle

Results of variable cycle engine (VCE) early acoustic engine and model scale tests are presented. A summary of an extensive series of far field acoustic, advanced acoustic, and exhaust plume velocity measurements with a laser velocimeter of inverted velocity and temperature profile, high radius ratio coannular plug nozzles on a YJ101 VCE static engine test vehicle are reviewed. Select model scale simulated flight acoustic measurements for an unsuppressed and a mechanical suppressed coannular plug nozzle are also discussed. The engine acoustic nozzle tests verify previous model scale noise reduction measurements. The engine measurements show 4 to 6 PNdB aft quadrant jet noise reduction and up to 7 PNdB forward quadrant shock noise reduction relative to a fully mixed conical nozzle at the same specific thrust and mixed pressure ratio. The influences of outer nozzle radius ratio, inner stream velocity ratio, and area ratio are discussed. Also, laser velocimeter measurements of mean velocity and turbulent velocity of the YJ101 engine are illustrated. Select model scale static and simulated flight acoustic measurements are shown which corroborate that coannular suppression is maintained in forward speed.

Knott, P. R.↗
DOE OSTI2022

Report on Year-4 of Water NSTF Matrix Testing: Facility Maintenance and Accident Testing

Under support from the Department of Energy (DOE) and the Office of Advanced Reactor Technologies (ART), a large-scale test facility has been constructed at Argonne National Laboratory to generate NQA-1 qualified validation data for passive decay heat removal systems in advanced reactors. The Natural convection Shutdown heat removal Test Facility (NSTF) reflects key features of a ½ scale, water-based, Reactor Cavity Cooling System (RCCS) and is intended to study the behavior, bound performance, and ultimately guide design decisions for passive decay heat removal systems for advanced reactors. In addition to the experimental activities detailed in this report, a supportive computational modeling effort is on-going which has been demonstrated to significantly strengthen the experimental program while also improving accuracy of the computer models. Together these create a mutually beneficial relationship integral to meeting the overall program objective of examining the heat removal performance of the RCCS concept. This report serves as a summary of maintenance and experimental activities during the program’s fourth year of water-based operation. A planned six-month maintenance period began in August 2021, during which major inspections, repairs, cleaning, and installation of new instrumentation and data acquisition hardware were conducted. Most significantly, two heaters that faulted during Year-3 were repaired, allowing the facility to resume use of the full heated section area and full range of available electric power. The remainder of the year consisted of eight months of test operations, during which the facility logged 211 hours of active heating across one bake-out (following the maintenance period) and seven matrix tests; five classifieds as Accepted per NQA-1, one as Trending, and one as Failed. Testing began by performing two repeat cases to confirm expected facility response and behavior during both single- and two-phase flow conditions, ensuring no changes were introduced during the maintenance period that might have altered the thermal-hydraulic characteristics of the facility. In continuation of the power parametric series initiated in previous years, a high-power test case was then performed examining heat removal performance at a decay heat load equivalent to 2.4 MWt, full-scale, a level exceeding maximum design targets. Additional testing then introduced various blockage scenarios along the network piping, examining the effects of partial and complete blockages of the flow paths on the system behavior and heat removal performance. A study of static boiling tests directed at understanding the geysering two-phase instability was also conducted. The loop was filled only to the bottom of the tank outlet, creating an open loop configuration that prevents any natural circulation flow from occurring, and the heaters were powered on until the facility reached saturation conditions. Following, a series of quasi-steady-state conditions were introduced by adjusting the inventory level in the adiabatic chimney piping at decreasingly lower elevations above the heated region. A strong correlation of geysering characteristics and loop level was observed, with flow and temperature excursions decreasing in intensity, but increasing in frequency, as the fill were reduced to lower elevations along the chimney piping. Once the level fell very low in the chimney, at points near the top of the heated section, the system reached a stable state of continuous boiling without any occurrence of geysering eruptions. A final significant testing accomplishment this year was successful completion of an “accident scenario” test, whose operating conditions were based on a prototypic decay heat curve provided by Framatome and scaled for the NSTF. This test began by establishing steady-state, single-phase “normal operation” conditions, before simulating an accident trip where the availability of active cooling systems was lost. Loop temperatures gradually increased until reaching saturation and subsequent two-phase boiling flow. Over the course of an extended operational period along the defined decay heat curve, steam boil-off caused gradual but continued depletion of liquid inventory until reaching a critically low level causing flow stagnation and cessation of natural circulation heat removal. At this point, after nearly 72 hours of continuous operation, a cold refill was performed to replenish the system inventory and allow the facility to re-establish closed loop natural circulation flow and return to a safe operational state.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS2017

Results of Large-Scale Spacecraft Flammability Tests

For the first time, a large-scale fire was intentionally set inside a spacecraft while in orbit. Testing in low gravity aboard spacecraft had been limited to samples of modest size: for thin fuels the longest samples burned were around 15 cm in length and thick fuel samples have been even smaller. This is despite the fact that fire is a catastrophic hazard for spaceflight and the spread and growth of a fire, combined with its interactions with the vehicle cannot be expected to scale linearly. While every type of occupied structure on earth has been the subject of full scale fire testing, this had never been attempted in space owing to the complexity, cost, risk and absence of a safe location. Thus, there is a gap in knowledge of fire behavior in spacecraft. The recent utilization of large, unmanned, resupply craft has provided the needed capability: a habitable but unoccupied spacecraft in low earth orbit. One such vehicle was used to study the flame spread over a 94 x 40.6 cm thin charring solid (fiberglasscotton fabric). The sample was an order of magnitude larger than anything studied to date in microgravity and was of sufficient scale that it consumed 1.5 of the available oxygen. The experiment which is called Saffire consisted of two tests, forward or concurrent flame spread (with the direction of flow) and opposed flame spread (against the direction of flow). The average forced air speed was 20 cms. For the concurrent flame spread test, the flame size remained constrained after the ignition transient, which is not the case in 1-g. These results were qualitatively different from those on earth where an upward-spreading flame on a sample of this size accelerates and grows. In addition, a curious effect of the chamber size is noted. Compared to previous microgravity work in smaller tunnels, the flame in the larger tunnel spread more slowly, even for a wider sample. This is attributed to the effect of flow acceleration in the smaller tunnels as a result of hot gas expansion. These results clearly demonstrate the unique features of purely forced flow in microgravity on flame spread, the dependence of flame behavior on the scale of the experiment, and the importance of full-scale testing for spacecraft fire safety.

microgravity↗
NASA NTRS2011

Validation and Simulation of Ares I Scale Model Acoustic Test - 2 - Simulations at 5 Foot Elevation for Evaluation of Launch Mount Effects

The Ares I Scale Model Acoustics Test (ASMAT) is a series of live-fire tests of scaled rocket motors meant to simulate the conditions of the Ares I launch configuration. These tests have provided a well documented set of high fidelity measurements useful for validation including data taken over a range of test conditions and containing phenomena like Ignition Over-Pressure and water suppression of acoustics. Expanding from initial simulations of the ASMAT setup in a held down configuration, simulations have been performed using the Loci/CHEM computational fluid dynamics software for ASMAT tests of the vehicle at 5 ft. elevation (100 ft. real vehicle elevation) with worst case drift in the direction of the launch tower. These tests have been performed without water suppression and have compared the acoustic emissions for launch structures with and without launch mounts. In addition, simulation results have also been compared to acoustic and imagery data collected from similar live-fire tests to assess the accuracy of the simulations. Simulations have shown a marked change in the pattern of emissions after removal of the launch mount with a reduction in the overall acoustic environment experienced by the vehicle and the formation of highly directed acoustic waves moving across the platform deck. Comparisons of simulation results to live-fire test data showed good amplitude and temporal correlation and imagery comparisons over the visible and infrared wavelengths showed qualitative capture of all plume and pressure wave evolution features.

Strutzenberg, Louise L.↗
NASA NTRS2016

Boeing Smart Rotor Full-scale Wind Tunnel Test Data Report

A full-scale helicopter smart material actuated rotor technology (SMART) rotor test was conducted in the USAF National Full-Scale Aerodynamics Complex 40- by 80-Foot Wind Tunnel at NASA Ames. The SMART rotor system is a five-bladed MD 902 bearingless rotor with active trailing-edge flaps. The flaps are actuated using piezoelectric actuators. Rotor performance, structural loads, and acoustic data were obtained over a wide range of rotor shaft angles of attack, thrust, and airspeeds. The primary test objective was to acquire unique validation data for the high-performance computing analyses developed under the Defense Advanced Research Project Agency (DARPA) Helicopter Quieting Program (HQP). Other research objectives included quantifying the ability of the on-blade flaps to achieve vibration reduction, rotor smoothing, and performance improvements. This data set of rotor performance and structural loads can be used for analytical and experimental comparison studies with other full-scale rotor systems and for analytical validation of computer simulation models. The purpose of this final data report is to document a comprehensive, highquality data set that includes only data points where the flap was actively controlled and each of the five flaps behaved in a similar manner.

Full-Scale Wind Tunnel↗
DOE OSTI2020

Advancing the science of explosive fragmentation and afterburn fireballs though experiments and simulations at the benchtop scale

Detonation of explosive devices produces extremely hazardous fragments and hot, luminous fireballs. Prior experimental investigations of these post-detonation environments have primarily considered devices containing hundreds of grams of explosives. While relevant to many applications, such large- scale testing also significantly restricts experimental diagnostics and provides limited data for model validation. As an alternative, the current work proposes experiments and simulations of the fragmentation and fireballs from commercial detonators with less than a gram of high explosive. As demonstrated here, reduced experimental hazards and increased optical access significantly expand the viability of advanced imaging and laser diagnostics. Notable developments include the first known validation of MHz-rate optical fragment tracking and the first ever Coherent Anti-Stokes Raman Scattering (CARS) measures of post-detonation fireball temperatures. While certainly not replacing the need for full-scale verification testing, this work demonstrates new opportunities to accelerate developments of diagnostics and predictive models of post-detonation environments.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
NASA NTRS1975

Acoustical characteristics of the NASA Langley full scale wind tunnel test section

The full-scale wind tunnel at NASA-Langley Research Center was designed for low-speed aerodynamic testing of aircraft. Sound absorbing treatment has been added to the ceiling and walls of the tunnel test section to create a more anechoic condition for taking acoustical measurements during aerodynamic tests. The results of an experimental investigation of the present acoustical characteristics of the tunnel test section are presented. The experimental program included measurements of ambient nosie levels existing during various tunnel operating conditions, investigation of the sound field produced by an omnidirectional source, and determination of sound field decay rates for impulsive noise excitation. A comparison of the current results with previous measurements shows that the added sound treatment has improved the acoustical condition of the tunnel test section. An analysis of the data indicate that sound reflections from the tunnel ground-board platform could create difficulties in the interpretation of actual test results.

Abrahamson, A. L.↗
NASA NTRS2020

Technology Demonstration Mission (TDM) Evolvable Cryogenics (eCryo) Project: Structural Heat Intercept, Insulation, and Vibration Evaluation Rig (SHIIVER) - Test Plan

The initial test of the SHIIVER system includes multilayer insulation and vapor cooled structure. Testing will occur in the In-Space Propulsion Facility (thermal/vacuum) and RATF (acoustic) facilities at Plum Brook Station in Sandusky Ohio. The testing will demonstrate the performance benefits of multilayer insulation and vapor based heat intercept on a “large scale” test article in a manner befitting large upper stages.

Large Scale Hydrogen Testing, Cryogenics, Multilay↗
NASA NTRS1990

Results of aerodynamic testing of large-scale wing sections in a simulated natural rain environment

The NASA Langley Research Center has developed a large-scale ground testing capability for evaluating the effect of heavy rain on airfoil lift. The paper presents the results obtained at the Langley Aircraft Landing Dynamics Facility on a 10-foot cord NACA 64-210 wing section equipped with a leading-edge slat and double-slotted trailing-edge flap deflected to simulate landing conditions. Aerodynamic lift data were obtained with and without the rain simulation system turned on for an angle-of-attack range of 7.5 to 19.5 deg and for two rainfall conditions: 9 in/hr and 40 in/hr. The results are compared to and correlated with previous small-scale wind tunnel results for the same airfoil section. It appears that to first order, scale effects are not large and the wind tunnel research technique can be used to predict rain effects on airplane performance.

Bezos, Gaudy M.↗
NASA NTRS2011

Ares I Scale Model Acoustic Test Above Deck Water Sound Suppression Results

The Ares I Scale Model Acoustic Test (ASMAT) program test matrix was designed to determine the acoustic reduction for the Liftoff acoustics (LOA) environment with an above deck water sound suppression system. The scale model test can be used to quantify the effectiveness of the water suppression system as well as optimize the systems necessary for the LOA noise reduction. Several water flow rates were tested to determine which rate provides the greatest acoustic reductions. Preliminary results are presented.

Counter, Douglas D.↗
NASA NTRSDate not supplied

Full Scale Flat Floor Testing of a 500-M2-Class Solar Sail Deployer

Solar sailing missions rely on deployable systemsfor large area to mass ratios once in space, whilestill being small enough for launcher envelopes inthe stowed configuration. Many of thesedeployable systems feature booms that areflattened and subsequently coiled onto aspool/hub. As part of a collaborative deployablespace structures research effort of NASA and DLR,a boom deployment mechanism for a future 500 m²solar sail has been developed since 2017. To achieve the respective solar sail size goal, 16.5m long booms produced by NASA were integratedinto a DLR-designed deployer mechanism. Thisconsiderable size, as well as the lightweightconstruction of the booms and respectivedeployable systems makes ground testing asignificant challenge. Some systems for gravitycompensation and boom alignment will bepresented in the paper. However, the main focus isthe functional flat floor testing of the integratedboom-deployment mechanism system, as well asits challenges. The testing performed includes full deployment aswell as stowage of the booms. Both have beenperformed multiple times. The latter is one of thekey parameters determining packaging efficiency,which in turn confirms design assumptions. Duringsystem development, small scale tests and modelshave been used in preparation of flat floor testingof the 33 m span cross of the full-scale booms anddeployment mechanism. Hence a small chapter isalso devoted to analysing the differences inbehaviour between small- and full-scaledeployment systems. More parameters that are vital to design decisionshave been determined this way, such as drivingbelt force or hub brake torque. This paper alsofocuses on development goals and needs forfuture steps to achieve higher levels of technologyreadiness, such as the balancing of driving motorforce, synchronisation of its transmission and thecountering hub brake torque

Deployment mechanism↗
DOE OSTI2022

A scalable compressible volume of fluid solver using a stratified flow model

Here, in this paper, a Volume of Fluid method which uses a Stratified Flow model for flux calculation is proposed to solve a compressible multiphase flow in a way that has high parallel efficiency. The solver is part of an open-source computing tool to study fuel entrainment and combustion in the application of paraffin-based hybrid rocket motors. This paper focuses on the compressible Volume of Fluid solver for the liquid and gaseous phases in this environment. This solver uses perfect gas and stiffened gas models for equation of state, with the ability to easily add other models as desired. Additionally a comparison of a Riemann solver versus an AUSM+up scheme is conducted, showing improvement with the later in the solution of multiphase flows. This solver successfully reproduces shock tube cases with the expected accuracy, as well as simulating two-dimensional shear and gravity-driven flows. Results also show that the code is able to utilize a Stratified Flow model to evaluate shear flow without the need for interface reconstruction or gradient calculations. Finally, it is shown that the solver has near-ideal scaling under strong scaling tests as well as good performance in static scaling, giving improved performance over current options and implying future advancement of high-performance computing efficiency for multiphase flow solvers.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2020

Advanced Modular Sub-Atmospheric Hybrid Heat Engine (Final Report)

The Phase 1 Final Technical Report describes the results of the work completed during the “Advanced Modular Sub-Atmospheric Hybrid Heat Engine” project. A key part of the Phase 1 work was the completion of a thermodynamic cycle analysis for the MHHE at the selected module size. The hybrid heat engine has been developed as a modular unit (sized in the range of 500kW – 60MW) that can be used with modular coal or biomass gasifiers, with distributed power generation systems, with large power plants comprised of multiple generating units, and with natural gas compression stations. The MHHE will provide cleaner, more efficient, and lower cost generation with better load following capabilities than existing competing technologies with a singular generating source such as solar farm, gas turbine, or combustion engine. The drivers of the MHHE technology are: benefits of modular power generation (reduced equipment cost, construction cost and implementation time, connection ready on delivery, flexible scalability, serviceability), fuel flexibility, lowest cost power generation and reduced emissions.A logical progression of work and a clear path forward toward meeting the FOA goals and objectives have been established. Namely, a preliminary market analysis and primary fuel identification was completed first and then the modularity of the system was defined. The benefits of the proposed hybrid and modular heat engine were described when applied to modular coal gasifiers, distributed power generators, and larger power plants. Based on the market analysis, modularity, and chosen primary fuel, a conceptual design and layout of the hybrid heat engine was developed, analyzed, and characterized. The technology gaps already identified have been reviewed and expanded upon, and a test plan to address these gaps through bench scale testing in Phase 2 has been developed. Cost estimate methodology and considerations in support of a potential Phase 2 project have been described.

08 HYDROGEN↗
DOE OSTI2020

Advanced Modular Sub-Atmospheric Hybrid Heat Engine (Phase 1 Final Report)

The Phase 1 Final Report describes the results of the work completed during the “Advanced Modular Sub-Atmospheric Hybrid Heat Engine” project. The objectives of Phase 1 work were to develop a conceptual design of the turbine-based modular hybrid heat engine (MHHE), including thermodynamic cycle analysis, define the nominal engine component boundary conditions, identify technology gaps, and develop a detailed test plan to address these gaps through bench scale testing in a potential subsequent Phase 2 project. To achieve the project objective, the following activities were performed in Phase 1 work: (1) Market analysis and primary fuel selection, (2) Conceptual design and integrated layout development, (3) Design support and key components characterization, (4) Planning to move technology to pre-commercial demonstration.

42 ENGINEERING↗
DOE OSTI2022

Predicting Asteroid Material Properties from a DART-like Kinetic Impact

Abstract NASA’s Double Asteroid Redirection Test (DART) mission is the first full-scale test of the kinetic impactor method for asteroid deflection, in which a spacecraft intentionally impacts an asteroid to change its trajectory. DART represents an important first step for planetary defense technology demonstration, providing a realistic assessment of the effectiveness of the kinetic impact approach on a near-Earth asteroid. The momentum imparted to the asteroid is transferred from the impacting spacecraft and enhanced by the momentum of material ejected from the impact site. However, the magnitude of the ejecta contribution is dependent on the material properties of the target. These properties, such as strength and shear modulus, are unknown for the DART target asteroid, Dimorphos, as well as most asteroids since such properties are difficult to characterize remotely. This study examines how hydrocode simulations can be used to estimate material properties from information available post-impact, specifically the asteroid size and shape, the velocity and properties of the impacting spacecraft, and the final velocity change imparted to the asteroid. Across >300 three-dimensional simulations varying seven material parameters describing the asteroid, we found many combinations of properties could reproduce a particular asteroid velocity. Additional observations, such as asteroid mass or crater size, are required to further constrain properties like asteroid strength or outcomes like the momentum enhancement provided by impact ejecta. Our results demonstrate the vital importance of having as much knowledge as possible prior to an impact mission, with key material parameters being the asteroid’s mass, porosity, strength, and elastic properties.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1975

Design and preliminary tests of a blade tip air mass injection system for vortex modification and possible noise reduction on a full-scale helicopter rotor

Full-scale tests were conducted on the Langley helicopter rotor test facility as part of a study to evaluate the effectiveness of a turbulent blade tip air mass injection system in alleviating the impulsive noise (blade slap) caused by blade-vortex interaction. Although blade-slap conditions could not be induced during these tests, qualitative results from flow visualization studies using smoke showed that the differential velocity between the jet velocity and the rotor tip speed was a primary parameter controlling the vortex modification.

Pegg, R. J.↗
NASA NTRS1976

Test data report: Low speed wind tunnel tests of a full scale, fixed geometry inlet, with engine, at high angles of attack

A full scale inlet test was to be done in the NASA-ARC 40' X 80' WT to demonstrate satisfactory inlet performance at high angles of attack. The inlet was designed to match a Hamilton-Standard 55 inch, variable pitch fan, driven by a Lycoming T55-L-11A gas generator. The test was installed in the wind tunnel on two separate occasions, but mechanical failures in the fan drive gear box early in each period terminated testing. A detailed description is included of the Model, installation, instrumentation and data reduction procedures.

Shain, W. M.↗
NASA NTRS1981

Large-scale wind tunnel tests of a sting-supported V/STOL fighter model at high angles of attack

A new sting model support has been developed for the NASA/Ames 40- by 80-Foot Wind Tunnel. This addition to the facility permits testing of relatively large models to large angles of attack or angles of yaw depending on model orientation. An initial test on the sting is described. This test used a 0.4-scale powered V/STOL model designed for testing at angles of attack to 90 deg and greater. A method for correcting wake blockage was developed and applied to the force and moment data. Samples of this data and results of surface-pressure measurements are presented.

Stoll, F.↗