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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 757 records · Page 42

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NASA NTRSDate not supplied

Plans for Ice Crystal Icing Tests Using a 3D Heated Test Article at the NASA Icing Research Tunnel

This presentation describes the plans for ice crystal icing and supercooled water icing tests to be conducted in Fall/Winter 2021 at the NASA Icing Research Tunnel. A test article, whose geometry is representative of an inter-compressor duct and strut region of a turbofan engine, has been designed and fabricated for the study of ice crystal icing physics tests. The Simulated Inter-compressor Duct Research Model (SIDRM) will have the ability to heat surfaces to simulate the warm surfaces of the inter-compressor duct within an engine. The test article is instrumented with heaters, heat flux gauges, thermocouples, and pressure taps to measure icing behavior. The aim of these tests is to generate ice shapes on the SIDRM test article under well-characterized conditions. The results of the testing with the SIDRM model will be used to provide icing physics and validation data for development of the engine icing simulation capabilities in GlennICE, the 3D ice prediction tool. This is intended to be a presentation only, and does not have an accompanying paper.

ice-crystal icing↗

NASA NTRSDate not supplied

Full-Envelope Aero-Propulsive Model Identification for Lift+Cruise Aircraft Using Computational Experiments

This paper describes a process utilizing computational fluid dynamics experiments to develop a reduced-order, integrated propulsion-airframe aerodynamic model for a lift+cruise electric vertical takeoff and landing (eVTOL) reference aircraft concept. eVTOL configurations exhibit aerodynamic characteristics of both fixed-wing and rotary-wing aircraft as well as complex phenomena, such as propulsion-airframe interactions. Consequently, conventional aircraft aerodynamic modeling strategies require modification when applied to these unique aircraft. A novel aero-propulsive modeling approach using design of experiments techniques and computational fluid dynamics simulations is postulated for modeling a lift+cruise aircraft configuration. Aero-propulsive models are developed throughout the operational flight envelope to enable continuous flight dynamics simulations from hover through forward flight. The model adequacy is assessed using validation data acquired separately from data used to identify the model and indicates that the models have sufficient predictive capability. Research findings are presented with a discussion of unique lift+cruise aircraft aerodynamic characteristics and practical strategies to inform future aero-propulsive modeling and simulation efforts for eVTOL aircraft.

lift+cruise↗

NASA NTRSDate not supplied

Strain Sensor Survey for Parachute Canopy Load Measurements

The parachute failures during the National Aeronautics and Space Administration Low-Density Supersonic Decelerator project revealed many of the complications of using parachutes for atmospheric entry missions and prompted the need for a more in-depth understanding of parachutes. Validation data for point loads on parachute canopies would contribute greatly to this understanding; however, such data does not exist because of a lack in practical sensing technologies capable of measuring the canopy strain. Few commercially available sensing technologies exist that can measure the total strain range of the parachute broadcloth materials, and even fewer can be easily integrated into the canopy. Additionally, many of these options are not at a technology readiness level suitable for flight-testing. This survey presents and compares the latest sensing capabilities that have potential in instrumenting parachute canopies for atmospheric entry and highlights the challenges particular to this application. Each sensor is evaluated for its performance and suitability towards parachute canopy instrumentation. Specifically, sensors are evaluated on their capabilities in measuring maximum strain, strain rate, hysteresis, drift, adherence and integration options, durability, environmental conditions, and technology maturation. Additionally, future work that is needed to assess sensor technologies for this application is provided.

Daniel W. Budolak↗

NASA NTRSDate not supplied

Estimation of 3D Woven Design Sensitivities Using a Rapid Multiscale Analysis Technique

Highly-refined finite element models of three-dimension (3D) woven composite systems currently require excessive computational demands that limit their use in sensitivity analysis, uncertainty quantification, and optimization. An alternative analysis methodology was developed using the NASA Multiscale Analysis Tool (NASMAT) where multiscale models of a 3D woven composite (including inter-tow matrix voids and constituent failure) can be completed on a single central processing unit(CPU)on the order of ~30 s. To develop inputs and validation data for the NASMAT model, coupon and acid-digesting testing and x-ray computed tomography were performed. The NASMAT inputs were parameterized using a set of 25 input variables and distributions. These inputs were randomly sampled to generate a total of 100,000 NASMAT analyses that could be used to understand the influence of different material and geometric properties on the warp and weft-direction stiffness and strength. These analyses (including pre/post-processing) were performed in less than eight hours on a 120 CPU cluster. The computational efficiency of the NASMAT model enabled a sensitivity analysis to be performed, and dominant input variables were able to be identified. Key results were consistent with theoretical and experimental observations for the specific 3D woven system studied in this work.

NASMAT↗

NASA NTRSDate not supplied

NASA Supersonics Research — Leading Toward Quiet Supersonic Flight!!

- Brief history of supersonic flight - Shock waves and sonic booms - Sonic boom pressure signatures and loudness - Tools for studying quiet supersonic flight - CFD (Computational Fluid Dynamics) - Wind tunnels - Flight test - Quesst Mission - X-59 airplane - Mission profile - Flight simulations - Wind tunnel data validations - Video: Supersonic flight research leading to Quesst

sonic boom↗

NASA NTRSDate not supplied

Estimation of 3D Woven Design Sensitivities Using a Rapid Multiscale Analysis Technique

Highly-refined finite element models of three-dimension (3D) woven composite systems currently require excessive computational demands that limit their use in sensitivity analysis, uncertainty quantification, and optimization. An alternative analysis methodology was developed using the NASA Multiscale Analysis Tool (NASMAT) where multiscale models of a 3D woven composite (including inter-tow matrix voids and constituent failure) can be completed on a single central processing unit (CPU) on the order of ~30s. To develop inputs and validation data for the NASMAT model, coupon and acid-digesting testing and x-ray computed tomography were performed. The NASMAT inputs were parameterized using a set of 25 input variables and distributions. These inputs were randomly sampled to generate a total of 100,000 NASMAT analyses that could be used to understand the influence of different material and geometric properties on the warp and weft-direction stiffness and strength. These analyses (including pre/post-processing) were performed in less than eight hours on a 120 CPU cluster. The computational efficiency of the NASMAT model enabled a sensitivity analysis to be performed, and dominant input variables were able to be identified. Key results were consistent with theoretical and experimental observations for the specific 3D woven system studied in this work.

NASMAT↗

NASA NTRS2022

TESS Data Release Notes: Sector 47, DR67

These Data Release Notes provide information on the processing and export of data from the Transiting Exoplanet Survey Satellite (TESS). The data products included in this data release are full frame images (FFIs), target pixel files, light curve files, collateral pixel files, cotrending basis vectors (CBVs), and Data Validation (DV) reports, time series, and associated xml files.

TESS↗

NASA NTRS2022

TESS Data Release Notes:Sector 48, DR70

TESS↗

NASA NTRS2022

TESS Data Release Notes: Sector 49, DR71

TESS↗

NASA NTRS2023

CFD Integrated Transition Modeling for High-Speed Flows via Coupled OVERFLOW-LASTRAC Analysis

This work details ongoing efforts at the NASA Langley Research Center to develop and validate a general-use CFD tool that includes built-in predictions of boundary-layer transition in high-speed flows. Existing tools for the coupling of the NASA OVERFLOW structured overset RANS solver and LASTRAC stability analysis code have been extended to capture boundary-layer transition in high-speed flows driven by either Mack’s first-mode or secondmode instabilities and/or crossflow instabilities. The efficacy of this coupled approach has been demonstrated by examining a variety of supersonic and hypersonic test cases for which experimental validation data is available. The intermittency prescription parameters inherited from prior low-speed applications are found to be suitable for some, but not all high-speed flow scenarios. The method is found to be robust for straight cone configurations and improvements necessary to accurately capture transition on geometries with spatially complex amplification factor envelopes with intermediate regions of slow N-factor variation are examined. The automated, coupled analysis is demonstrated for a 3d supersonic test case and found to perform well within the limits of the linear stability analysis on which it relies. Finally, a preliminary investigation of the method’s robustness to non-ideal CFD meshes is conducted.

High-speed flow↗

NASA NTRS2023

A Cloud Detection Neural Network for Above-Aircraft Clouds Using Airborne Cameras

We introduce a method convolutional neural networks to detect the presence of clouds in airborne camera images. We quantify the performance of this Cloud Detection Neural Network (CDNN) using human-labeled validation data where we report a 96% accuracy in detecting clouds in testing datasets for both Zenith- viewing and Forward-viewing models. We assess our performance by comparing the flight-averaged cloud fraction of zenith and forward CDNN retrievals, with that of the prototype hyperspectral total-diffuse Sunshine Pyranometer (SPN-S) instrument’s cloud optical depth data. Comparison of the CDNN with the SPN-S on time specific intervals resulted in 93% accuracy for the zenith- viewing CDNN and 84% for the forward- viewing CDNN. The comparison of the CDNNs with the SPN-S on flight-averaged cloud fraction resulted in an agreement of 0.15 for the Forward CDNN and 0.07 for the Zenith CDNN. We then quantify the ability of the CDNN to identify the presence of clouds above the aircraft using a forward- looking camera mounted inside the aircraft cockpit compared to the use of an All- Sky upward-looking camera that is mounted outside the fuselage on top of the aircraft. We present results from the CDNN based on airborne imagery from the NASA Aerosol Cloud Meteorology Interactions Over the Western Atlantic Experiment (ACTIVATE) and the Clouds, Aerosol and Monsoon Processes- Philippines Experiment (CAMP2Ex). For CAMP2Ex 53% of flight dates had above- aircraft cloud fraction above 50%, while for ACTIVATE 52% and 54% of flight dates observed above-aircraft cloud fraction above 50% for 2020 and 2021, respectively.

Joseph D Nied↗

NASA NTRSDate not supplied

NASA Supersonics Research and the X-59 — How They Will Benefit You!!

sonic boom↗

NASA NTRSDate not supplied

Assimilation of GEO and LEO Satellite Retrievals in WRF-Chem (15 km and 4 km) with ‘Top-Down’ Emissions Estimation

We are constraining concentrations and emissions for all criteria pollutants (CO, O3, NO2, SO2, PM10, and PM2.5) with WRF-Chem/DART in applications for FRAPPE (15-km grid) and COLORADO (4-km grid). Our results show that: (i) dynamic emissions estimation at medium resolutions (15 km) improves forecast skill; (ii) At high resolutions, the results look good, but we do not have validation data; (iii) for what may be the first time, we assimilate O3 retrieval profiles in a regional model. The problem is that the averaging kernels generally extend above the upper boundary of regional models. We use O3 upper boundary conditions from the global model to solve that problem; and (iv) In the high resolution experiments, we document the potential benefits of assimilating TEMPO O3 profile and NO2 tropospheric column retrievals. Here, we assimilate proxy TEMPO retrievals from a GEOS-Chem nature run, so there’s a conceptual problem due to the potential bias of the proxy retrievals, but the point is to demonstrate our ability to assimilate TEMPO and identify its potential impacts.

Chemical data assimilation↗

NASA NTRS2022

TESS Data Release Notes: Sector 57, DR82

TESS↗

NASA NTRSDate not supplied

Nasa Supersonics Research and the X-59 —To Enable Future Supersonic Travel!

sonic boom↗

NASA NTRSDate not supplied

Experimental Characterization of an Electric Ducted Fan for the SUSAN 25% Scale Research Vehicle

An electric ducted fan (EDF) was tested in the NASA Langley 12-Foot Low-Speed Tunnel for the SUbsonic Single Aft eNgine (SUSAN) Electrofan 25% scale research vehicle, which incorporates distributed electric fans along the wings and serves as a scaled electrified transport aircraft testbed. The commercial-off-the-shelf EDF was selected as a propulsor that can meet the 25% scale vehicle geometry constraints, along with the performance requirements throughout the flight profile. The test included a series of one-factor-at-a-time (OFAT) and design of experiments (DOE) approaches that were implemented across a range of fan speed, voltage, freestream dynamic pressure, and incidence angle settings to characterize the performance of the EDF. Several test matrix designs and modeling approaches were considered. System identification methods were used to develop a static motor model, a dynamic motor model, an EDF thrust model, and a power consumption model. The model predictive capabilities were then evaluated with validation data not used in the modeling process. The results provide a comprehensive set of models developed to characterize the fan, and offer general insight into EDF modeling approaches.

electric ducted fan↗

NASA NTRSDate not supplied

Aerothermodynamic Analyses for the LOFTID Technology Demonstration Mission

On November 10, 2023, the LOFTID flight test successfully demonstrated the aerodynamic and thermal protection system performance of an inflatable aeroshell at conditions relevant to an operational mission. Aerodynamic performance and aeroheating environment databases for this mission were generated using multiple computational tools for the rarefied, hypersonic, and supersonic flow regimes, supplemented by wind tunnel testing to obtain aeroshell boundary-layer transition and wake flow simulation validation data. A detailed discussion of tools, methods and results is presented herein.

Brian R. Hollis↗

NASA NTRSDate not supplied

Characterization Progress of an Absorption Laser Differential Interferometer

An absorption laser differential interferometer (A-LDI) system can be used to provide simultaneous, colinear measurements of flow properties (pressure, temperature, concentration, velocity) and flow fluctuations. Further characterization work on the absorption aspect of the system is provided in this paper, including characterization of the laser operating parameters, comparisons of two etalons of different free spectral range, and the further evaluation of a fixed-wavelength absorption measurement that can be used to obtain absorption and LDI measurements with the same sampling rate. A 0.4 GHz etalon was demonstrated to provide sufficient fringe peaks at low modulation depths to be used for the low-pressure testing characteristic of hypersonic wind tunnel facilities. The use of a 3 GHz etalon as a low-cost relative wavemeter was tested and validated. Data taken with the fixed-wavelength strategy in a sub-atmospheric test cell using 100% O2was successful and will allow absorption and LDI data to be acquired simultaneously, colinearly, and at the same sampling rate, yielding a truly simultaneous measurement of the flow density fluctuations and the flow mean density.

Joshua M Weisberger↗