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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 343 records · Page 19

Verification of performance results for a low-speed 15 percent elliptical circulation control airfoil

Low-speed wind tunnel tests performed by the Naval Ship Research and Development Center (NSRDC) on a circulation control airfoil model was repeated by the Joint Institute for Aerodynamics and Acoustics in an attempt to reproduce the performance results. The model used was a 15% ellipse with interchangeable trailing edges. Surface pressure measurements were taken to obtain lift and pitching moment coefficients as functions of jet blowing momentum, and the momentum deficit in the wake was measured and used to calculate the drag coefficient. The effects of spanwise slot height variation and of leading edge blowing on performance were also investigated. The performance results showed that of the three slot heights tested, a slot height/chord ratio of 0.0022 produced the most lift coefficient for a given blowing rate. Lift obtained in the current test ranged from 2 to 35% lower than the NSRDC test. However, the two data sets compared reasonably well considering wind tunnel and wall blowing scheme differences. The spanwise lift distribution showed less change in lift due to a variation in slot height than expected. The leading edge blowing results demonstrated that although lift initially decreased, a positive lift increment was possible at higher leading edge blowing rates.

Rodman, L. C.↗

Analytical modeling of helium II in forced flow conditions

A numerical model was developed to examine the flow behavior of He II under forced flow conditions. The model basically solves the governing equations in the two-fluid model of He II, and can be used to assess the pump requirement for transferring He II in spaceborne systems. Predictions of liquid temperature and pressure drop agree well with empirical data obtained from small scale tests. At high transfer rates, the model predicts that the forced convection dominates the Gorter-Mellink conduction in heat transfer, and the classical turbulent flow correlation is sufficient for calculating the pressure drop across the transfer line.

Ng, Y. S.↗

Controlled-strain rate tests at very low strain rates of 2618 aluminum at 200 C

Constant strain rate tests and constant load creep tests were performed on 2618 aluminum at 200 C. The strain rates used in the constant strain rate tests were 10 to the minus 6, 10 to the minus 7, 10 to the minum 8, and 10 to the minus 9/sec. Due to the fact that the strain rates in both tests were comparable to each other, the similarities between them can therefore be studied. It was concluded that metals are essentially rate sensitive at elevated temperatures. The traditional definition of creep and plasticity used in the classical creep analysis is actually a reflection of the material behavior under different loading conditions. A constitutive equation based on the test data under one loading condition should work well for other loading conditions as long as the strain rates are in the same range as those under which the material constants are determined.

Ding, J. L.↗

Atomization modeling in a multiphase flow environment and comparison with experiments

An atomization model based on Reitz's instability wave analysis has been implemented into the ARICC3D multiphase CFD combustion code. Preliminary test runs with cold non-evaporating liquid jet and coaxial gas-liquid atomization cases appeared to have verified basic performance of the model, generating realistic-looking sprays. Furthermore, the extended liquid jet is explicitly resolved, and predicted jet lengths agree well with classical correlations. Fair agreement with test data is obtained for predicted spray tip penetrations and liquid mass flux radial distributions, with obvious room for improvement. Some numerical problems also appear to have resulted with the current implementation when low gas Mach number and high liquid velocities are involved.

Liang, P. Y.↗

Detailed measurements in the SSME high pressure fuel turbine with smooth rotor blades

Several tests of the Rocketdyne configuration of the Space Shuttle Main Engine (SSME) High Pressure Fuel Turbopump (HPFTP) Turbine have been completed in the Turbine Test Equipment (TTE) at Marshall Space Flight Center. The tests involved using scaled performance parameters and model measurements to predict the performance of the turbine. The overall performance has been the primary objective of the tests to date, but more detailed measurements are also of interest. During the most recent test of the Rocketdyne configuration of the HPFTP turbine with smooth rotor blades, several different measurement techniques were used to study the turbine inlet and exit velocity profiles, boundary layer thicknesses, turbulence intensities, etc. Data has been obtained using various hot film probes and three-hole cobra probes. Laser Velocimeter measurements were also made. The test plan and test data will be presented and discussed as well as lessons learned on how to obtain the various types of data.

Hudson, Susan T.↗

Panasonic Small Cell Testing for AHPS

AEA selection and successful Interim Design Review for AHPS proves maturity of small cell approach for very large batteries. Cells show excellent opportunity for battery mass reduction for AHPS and other low cycle applications. Lack of cycle and extended calendar life make EOL battery performance difficult (AHPS 8 year mission). Preliminary design, AEA retained SONY 18650HC cell as baseline: a) Well characterized performance; b) Wealth of safety test data.

Pearson, C.↗

One Dimensional Analysis Model of a Condensing Spray Chamber Including Rocket Exhaust Using SINDA/FLUINT and CEA

Modeling droplet condensation via CFD codes can be very tedious, time consuming, and inaccurate. CFD codes may be tedious and time consuming in terms of using Lagrangian particle tracking approaches or particle sizing bins. Also since many codes ignore conduction through the droplet and or the degradating effect of heat and mass transfer if noncondensible species are present, the solutions may be inaccurate. The modeling of a condensing spray chamber where the significant size of the water droplets and the time and distance these droplets take to fall, can make the effect of droplet conduction a physical factor that needs to be considered in the model. Furthermore the presence of even a relatively small amount of noncondensible has been shown to reduce the amount of condensation. It is desirable then to create a modeling tool that addresses these issues. The path taken to create such a tool is illustrated. The application of this tool and subsequent results are based on the spray chamber in the Spacecraft Propulsion Research Facility (B2) located at NASA's Plum Brook Station that tested an RL-10 engine. The platform upon which the condensation physics is modeled is SINDAFLUINT. The use of SINDAFLUINT enables the ability to model various aspects of the entire testing facility, including the rocket exhaust duct flow and heat transfer to the exhaust duct wall. The ejector pumping system of the spray chamber is also easily implemented via SINDAFLUINT. The goal is to create a transient one dimensional flow and heat transfer model beginning at the rocket, continuing through the condensing spray chamber, and finally ending with the ejector pumping system. However the model of the condensing spray chamber may be run independently of the rocket and ejector systems detail, with only appropriate mass flow boundary conditions placed at the entrance and exit of the condensing spray chamber model. The model of the condensing spray chamber takes into account droplet conduction as well as the degrading effect of mass and heat transfer due to the presence of noncondensibles. The one dimension model of the condensing spray chamber makes no presupposition on the pressure profile within the chamber, allowing the implemented droplet physics of heat and mass transfer coupled to the SINDAFLUINT solver to determine a transient pressure profile of the condensing spray chamber. Model results compare well to the RL-10 engine pressure test data.

Chemical Equilibrium↗

One Dimensional Analysis Model of a Condensing Spray Chamber Including Rocket Exhaust Using SINDA/FLUINT and CEA

Modeling droplet condensation via CFD codes can be very tedious, time consuming, and inaccurate. CFD codes may be tedious and time consuming in terms of using Lagrangian particle tracking approaches or particle sizing bins. Also since many codes ignore conduction through the droplet and or the degradating effect of heat and mass transfer if noncondensible species are present, the solutions may be inaccurate. The modeling of a condensing spray chamber where the significant size of the water droplets and the time and distance these droplets take to fall, can make the effect of droplet conduction a physical factor that needs to be considered in the model. Furthermore the presence of even a relatively small amount of noncondensible has been shown to reduce the amount of condensation [Ref 1]. It is desirable then to create a modeling tool that addresses these issues. The path taken to create such a tool is illustrated. The application of this tool and subsequent results are based on the spray chamber in the Spacecraft Propulsion Research Facility (B2) located at NASA's Plum Brook Station that tested an RL-10 engine. The platform upon which the condensation physics is modeled is SINDAFLUINT. The use of SINDAFLUINT enables the ability to model various aspects of the entire testing facility, including the rocket exhaust duct flow and heat transfer to the exhaust duct wall. The ejector pumping system of the spray chamber is also easily implemented via SINDAFLUINT. The goal is to create a transient one dimensional flow and heat transfer model beginning at the rocket, continuing through the condensing spray chamber, and finally ending with the ejector pumping system. However the model of the condensing spray chamber may be run independently of the rocket and ejector systems detail, with only appropriate mass flow boundary conditions placed at the entrance and exit of the condensing spray chamber model. The model of the condensing spray chamber takes into account droplet conduction as well as the degrading effect of mass and heat transfer due to the presence of noncondensibles. The one dimension model of the condensing spray chamber makes no presupposition on the pressure profile within the chamber, allowing the implemented droplet physics of heat and mass transfer coupled to the SINDAFLUINT solver to determine a transient pressure profile of the condensing spray chamber. Model results compare well to the RL-10 engine pressure test data.

Condensing Spray Model↗

A Review of Head-Worn Display Research at NASA Langley Research Center

NASA Langley has conducted research in the area of helmet-mounted/head-worn displays over the past 30 years. Initially, NASA Langley's research focused on military applications, but recently it has conducted a line of research in the area of head-worn displays for commercial and business aircraft. This work has revolved around numerous simulation experiments as well as flight tests to develop technology and data for industry and regulatory guidance. The paper summarizes the results of NASA's helmet-mounted/head-worn display research. Of note, the work tracks progress in wearable collimated optics, head tracking, latency reduction, and weight. The research lends credence that a small, sunglasses-type form factor of the head-worn display would be acceptable to commercial pilots, and this goal is now becoming technologically feasible. The research further suggests that a head-worn display may serve as an "equivalent" Head-Up Display (HUD) with safety, operational, and cost benefits. "HUD equivalence" appears to be the economic avenue by which head-worn displays can become main-stream on the commercial and business aircraft flight deck. If this happens, NASA's research suggests that additional operational benefits using the unique capabilities of the head-worn display can open up new operational paradigms.

Arthur, Jarvis (Trey) J., III↗

Advances Towards Ingestion of Multi-Instrument Cloud-Cleared Infrared Radiances in a Global Data Assimilation and Forecast Framework

The progress towards the assimilation of hyperspectral infrared radiances affected by clouds in the NASA GEOS system is presented. After positive published results describing the assimilation of adaptively thinned AIRS cloud-cleared radiances in the 3DVAR GEOS, this team has then successfully tested adaptively thinned CrIS and IASI data as well, and then moved to assimilation in a hybrid 4DEnVAR configuration. The latest effort is focused on the creation of a portable, customizable version of the cloud-clearing algorithm that is being tailored for the hybrid 4DEnVAR system.

Reale, Oreste↗

The Mid-IR Spectral Effects of Darkening Agents and Porosity on the Silicate Surface Features of Airless Bodies

We systematically measured the mid-IR spectra of different mixtures of three silicates (antigorite, lizardite, and pure silica) with varying effective porosities and amounts of darkening agent (iron oxide and carbon). These spectra have broad implications for interpretation of current and future mission data for airless bodies, as well as for testing the capabilities of new instruments. Serpentines, such as antigorite and lizardite, are common to airless surfaces, and their mid-IR spectra in the presence of darkening agents and different surface porosities would be typical for those measured by spacecraft. Silica has only been measured in the plumes of Enceladus and presents exciting possibilities for other Saturn-system surfaces due to long range transport of E-ring material. Results show that the addition of the IR-transparent salt, KBr, to simulate surface porosity affected silicate spectra in ways that were not predictable from linear mixing models. The strengthening of silicate bands with increasing pore space, even when only trace amounts of KBr were added, indicates that spectral features of porous surfaces are more detectable in the mid-IR. Combining iron oxide with the pure silicates seemed to flatten most of the silicate features, but strengthened the reststrahlen band of the silica. Incorporating carbon with the silicates weakened all silicate features, but the silica bands were more resistant to being diminished, indicating silica may be more detectable in the mid-IR than the serpentines. We show how incorporating darkening agents and porosity provides a more complete explanation of the mid-IR spectral features previously reported on worlds such as Iapetus.

Young, Cindy L.↗

All-Electric X-Plane, X-57 Mod II Ground Vibration Test

As part of the National Aeronautics and Space Administration New Aviation Horizons initiative to demonstrate and validate future high-impact concepts and technologies, the X-57 Maxwell airplane--the first all-electric X-plane--was conceived to advance research in the area of electric propulsion to show the feasibility of minimizing fuel use, reducing emissions, and lowering noise during flight. Through several configuration modifications to the X-57 airplane, validation of electrical-powered flight with increasing efficiency between each modification when compared to the baseline original airplane is anticipated. In the case of the X-57 Modification II airplane, a ground vibration test was needed to identify the airplane structural modes and use them to update and validate the finite element model. To determine the airworthiness of the airplane the updated finite element model will be utilized to investigate both classical and whirl flutter. The X-57ModificationII ground vibration test was performed by the National Aeronautics and Space Administration Armstrong Flight Research Center Flight Loads Laboratory. This paper will highlight the testing performed to acquire the modal data as well as the results.

Natalie Dawn Spivey↗

Jet Noise Flyover and Scale Model Tests

Renewed interest in commercial supersonic flight has rekindled the need for accurate jet-noise predictions as this source is believed to dominate at aircraft takeoff conditions. The current study compares scale-model data acquired in the NASA Aero-Acoustic Propulsion Laboratory with data obtained using a well-instrumented Learjet 25 in a flyover test completed in September 2022. The flight test included 73 flyovers with engine conditions ranging from 1.5 to 2.0 engine pressure ratios and flight Mach numbers between 0.24 and 0.27. Acoustic data were acquired with an 800-ft linear ground plate microphone array. Wind speed data were acquired up to 1000-ft altitude with a ground-based LiDAR system. Layered ambient temperature, pressure, and humidity were acquired with a weather drone. A 6% increase in the physical scale factor for the scale-model data was found to reasonably align the peak frequencies of the scale-model and flight data and resulted in peak levels for the scale model being roughly 0.7 dB above those for the flight data at NPR = 1.56 and roughly 1 dB below those for the flight data at NPR = 1.91 in the peak jet-noise direction. Comparisons with the SAE ARP876 model were poor especially at emission angles greater than, or equal to, 110° and at high frequencies.

jet noise, supersonic transport↗

Jet Noise Flyover and Scale Model Tests

Renewed interest in commercial supersonic flight has rekindled the need for accurate jet-noise predictions as this source is believed to dominate at aircraft takeoff conditions. The current study compares scale-model data acquired in the NASA Aero-Acoustic Propulsion Laboratory with data obtained using a well-instrumented Learjet 25D in a flyover test completed in September 2022. The flight test included 73 flyovers with engine conditions ranging from 1.5 to 2.0 engine pressure ratios and flight Mach numbers between 0.24 and 0.27. Acoustic data were acquired with an 800-ft linear ground plate microphone array. Wind speed data were acquired up to 1000-sft altitude with a ground-based LiDAR system. Layered ambient temperature, pressure, and humidity were acquired with a weather drone. A 6% increase in the physical scale factor for the scale-model data was found to reasonably align the peak frequencies of the scale-model and flight data and resulted in peak levels for the scale model being roughly 0.7 dB above those for the flight data at NPR = 1.56 and roughly 1 dB below those for the flight data at NPR = 1.91 in the peak jet-noise direction. Comparisons with the SAE ARP876 model were poor especially at emission angles greater than, or equal to, 110° and at high frequencies.

Acoustics, jet noise, supersonic transport↗

Jet Noise Flyover and Scale Model Tests

Renewed interest in commercial supersonic flight has rekindled the need for accurate jet-noise predictions as this source is believed to dominate at aircraft takeoff conditions. The current study compares scale-model data acquired in the NASA Aero-Acoustic Propulsion Laboratory with data obtained using a well-instrumented Learjet 25 in a flyover test completed in September 2022. The flight test included 73 flyovers with engine conditions ranging from 1.5 to 2.0 engine pressure ratios and flight Mach numbers between 0.24 and 0.27. Acoustic data were acquired with an 800-ft linear ground plate microphone array. Wind speed data were acquired up to 1000-ft altitude with a ground-based LiDAR system. Layered ambient temperature, pressure, and humidity were acquired with a weather drone. A 6% increase in the physical scale factor for the scale-model data was found to reasonably align the peak frequencies of the scale-model and flight data and resulted in peak levels for the scale model being roughly 0.7 dB above those for the flight data at NPR = 1.56 and roughly 1 dB below those for the flight data at NPR = 1.91 in the peak jet-noise direction. Comparisons with the SAE ARP876 model were poor especially at emission angles greater than, or equal to, 110° and at high frequencies.

Acoustics, jet noise, supersonic transport↗

Portable Integrated Wireless Device Threat Assessment to Aircraft Radio Systems

An assessment was conducted on multiple wireless local area network (WLAN) devices using the three wireless standards for spurious radiated emissions to determine their threat to aircraft radio navigation systems. The measurement process, data and analysis are provided for devices tested using IEEE 802.11a, IEEE 802.11b, and Bluetooth as well as data from portable laptops/tablet PCs and PDAs (grouping known as PEDs). A comparison was made between wireless LAN devices and portable electronic devices. Spurious radiated emissions were investigated in the radio frequency bands for the following aircraft systems: Instrument Landing System Localizer and Glideslope, Very High Frequency (VHF) Communication, VHF Omnidirectional Range, Traffic Collision Avoidance System, Air Traffic Control Radar Beacon System, Microwave Landing System and Global Positioning System. Since several of the contiguous navigation systems were grouped under one encompassing measurement frequency band, there were five measurement frequency bands where spurious radiated emissions data were collected for the PEDs and WLAN devices. The report also provides a comparison between emissions data and regulatory emission limit.

Salud, Maria Theresa P.↗