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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Prediction of in-depth gap heating ratios from wing glove model test data

In-depth gap heating ratios were predicted down RSI tile sidewalls based on temperature measurements obtained from the JSC arc-jet Wing Glove model tests in order to develop gap heating ratios which resulted in the best possible fit of test data and to produce a set of engineering verification heating ratios similar in shape to one another which could be used at various body points on the Orbiter during reentry. The Rockwell TPS Multidimensional heat conduction program was used to perform 3-D thermal analyses using a 3.0 in. thick section of a curved RSI tile with 283 nodal points. Correlation with test data shows that the predicted heating ratios were significantly higher down in the gap than the zero pressure values for T/C stacks 39 and 38 on the Wing Glove model. For stack 37 (in a low pressure region), the baseline heating ratio overpredicted the temperature data. This analysis, which showed that the heating ratios were a strong function of the product of pressure and pressure gradient, will be used to compare with recent Gap/Step and Ames Double Wedge test/analysis results in the effort to identify the Orbiter gap response to high delta P flight environment.

Source record↗
NASA NTRS1973

Shuttle active thermal control system development testing. Volume 3: Modular radiator system test data correlation with thermal model

Results are presented of an analysis which compares the performance predictions of a thermal model of a multi-panel modular radiator system with thermal vacuum test data. Comparisons between measured and predicted individual panel outlet temperatures and pressure drops and system outlet temperatures have been made over the full range of heat loads, environments and plumbing arrangements expected for the shuttle radiators. Both two sided and one sided radiation have been included. The model predictions show excellent agreement with the test data for the maximum design conditions of high load and hot environment. Predictions under minimum design conditions of low load-cold environments indicate good agreement with the measured data, but evaluation of low load predictions should consider the possibility of parallel flow instabilities due to main system freezing. Performance predictions under intermediate conditions in which the majority of the flow is not in either the main or prime system are adequate although model improvements in this area may be desired. The primary modeling objective of providing an analytical technique for performance predictions of a multi-panel radiator system under the design conditions has been met.

Phillips, M. A.↗
DOE OSTI2018

Triton Point Absorber 1:30 Scale Tank Test Data for Extreme Wave Environments

This content model summarizes laboratory testing data for the Oscilla Power Triton WEC conducted at 1:30 scale. The WEC was tested in large operational waves and in extreme wave conditions along the 1 in 50 year wave contour at the DoE reference location in Humbolt Bay, CA. The WEC was tested in both its operational configuration and its survival configuration. The aims of the dataset are (i) To demonstrate that the survival strategy developed for the Triton WEC improves survivability and reduces loads in extreme wave environments, and (ii) To determine the ultimate design loads for the WEC.

16 TIDAL AND WAVE POWER↗
NASA NTRS1975

Outdoor flat-plate collector performance prediction from solar simulator test data

This paper describes how collector performance obtained from test data with a simulator can be modified for real-life conditions. The approach taken is to correct the performance data obtained with the simulator for the variable conditions of ambient temperature, wind, incident angle, flow rate, etc., that are encountered in outdoor conditions. Modification of simulator data is accomplished by combining experiment with theory. The technique is demonstrated by application to a spectrally selective and a nonselective type of collector. This kind of modified simulator collector performance data should be valuable in solar systems analyses and for collector performance ranking based on all-day calculated conditions.

Simon, F. F.↗
NASA NTRS1981

Comparisons of AEROX computer program predictions of lift and induced drag with flight test data

The AEROX aerodynamic computer program which provides accurate predictions of induced drag and trim drag for the full angle of attack range and for Mach numbers from 0.4 to 3.0 is described. This capability is demonstrated comparing flight test data and AEROX predictions for 17 different tactical aircraft. Values of minimum (skin friction, pressure, and zero lift wave) drag coefficients and lift coefficient offset due to camber (when required) were input from the flight test data to produce total lift and drag curves. The comparisons of trimmed lift drag polars show excellent agreement between the AEROX predictions and the in flight measurements.

Axelson, J.↗
NASA NTRS1992

Digital time series analysis for flutter test data

An application of digital time series analysis to flutter test data processing was conducted. A numerical investigation was used to evaluate the method, as well as its sensitivity to noise and parameter variations. These parameters included those involved with data acquisition, as well as system response characteristics. This digital time series method was then used to predict flutter speed from subcritical response wind tunnel tests. Flutter speeds predicted from forced response, subcritical wind tunnel tests were compared to the experimental flutter speeds.

Batill, S. M.↗
NASA NTRS1981

Development of a simple, self-contained flight test data acquisition system

This paper describes a simple, self-contained flight test data acquisition system. The system makes use of the latest sensor and microprocessor technology available, to reduce overall system costs. Coupled with this is the use of modern control theory techniques allowing minimization of data requirements, as well as flight time requirements. Capability of the system includes primarily stability and performance analysis of general aviation airplanes, although system versatility has been designed into the package. Presented are details of the prototype system constructed, as well as details of the data reduction technique utilized. Preliminary results of the flight test program have also been included which demonstrate the capability of this system.

Renz, R. R. L.↗
NASA NTRS2005

Liquid Nitrogen (Oxygen Simulant) Thermodynamic Vent System Test Data Analysis

In designing systems for the long-term storage of cryogens in low-gravity (space) environments, one must consider the effects of thermal stratification on tank pressure that will occur due to environmental heat leaks. During low-gravity operations, a Thermodynamic Vent System (TVS) concept is expected to maintain tank pressure without propellant resettling. A series of TVS tests was conducted at NASA Marshall Space Flight Center (MSFC) using liquid nitrogen (LN2) as a liquid oxygen (LO2) simulant. The tests were performed at tank til1 levels of 90%, 50%, and 25%, and with a specified tank pressure control band. A transient one-dimensional TVS performance program is used to analyze and correlate the test data for all three fill levels. Predictions and comparisons of ullage pressure and temperature and bulk liquid saturation pressure and temperature with test data are presented.

Hedayat, A.↗
NASA NTRS1997

Laboratory test data on the stability of the STIS MAMAs

STIS has two MAMA detectors systems with distinctly different tube configurations. The first (designated BAND 1) has an opaque CsI photocathode deposited on the microchannel plate (MCP) providing wavelength coverage from 1150A to 1700A. The other MAMA (designated BAND 2) has a semitransparent CS2Te photocathode deposited on the faceplate in close proximity to the input of the MCP. It covers the 1650A to 3100A bandpass and serves as a backup for the short wavelength detector. Laboratory test data indicate that both of these detectors have good sensitivity, have good uniformity and provide stable response, making each capable of collecting data with a signal-to-noise ratio in excess of 100 per Space Telescope Imaging Spectrograph (STIS) optical resolution element. Over a multiyear development effort, a substantial body of laboratory test data (more than 6 GBytes spanning more than 6 years of collection) has accumulated on more than a dozen fabricated tubes. These tests even included a few destructive evaluations to examine the limitations and operating life. In addition, analyses where conducted regarding impact caused by the specified electronic tolerances and expected changes in the Hubble Space Telescope (HST) thermal environment. Perhaps the simplest test of stability is to collect a sequence of images, each with a uniform illumination, and use these individual "flat fields" to remove the pixel-to-pixel sensitivity in the other flat fields. These sequences typically spanned 3-5 weeks of time. The detectors are very stable, allowing the pixel-to-pixel sensitivity to be removed with good precision. The STIS specification for stability is 1% (sufficient for data with a S/N = 100) over a 1 week period and 2% over 30 days. All Engineering Model Units as well as Flight Detectors tested exceeded this specification.

Joseph, Charles L.↗
NASA NTRSDate not supplied

Using Distributed Fiber-optic Strain Sensing to Estimate Generalized Modal Coordinates from Flight-test Data

A method for estimating the generalized modal coordinates of an aircraft during flight has been developed. The Fiber-optic Sensing System (FOSS) offers an efficient and cost-effective method of measuring the strain at thousands of points along the wings. The estimation of modal coordinates was implemented as a two-step process. First, a maximum likelihood method is used to estimate the statistical properties of the sensors and generalized modal coordinates. Second, the strain mode shapes from the finite element model are used along with the statistical properties from the first step to estimate the generalized modal coordinates over time. Using simulated data from the X-56A Multi-Utility Technology Testbed (MUTT), different methods of modal coordinate estimation were compared to demonstrate the benefits and weaknesses of each. These were compared against the exact solution and an ordinary least squares (a more traditional method) estimate. Modal coordinate estimation methods were then applied to flight-test data from the X-56A aircraft to show that the method continues to work well with actual test data. The new estimation method provides insights unavailable from more classical approaches.

Jeffrey Ouellette↗
NASA NTRS2024

Tiltrotor Test Rig Wind-Tunnel Test Data Catalog

The Tiltrotor Test Rig (TTR) is a large-scale proprotor test system for the National Full-Scale Aerodynamics Complex (NFAC). The first wind-tunnel entry was completed in November 2018 with a modern, 26-ft diameter proprotor. The rotor tested was the Bell Model 699, an AW609 rotor modified specifically for wind-tunnel testing. The primary purpose was to complete the development of the TTR, including systems integration with the NFAC. Testing included axial flow up to 273 knots, conversion mode from 30 to 100 deg nacelle angle, and hover/vertical climb conditions. Additional testing included aerodynamic tares, motor tests, thermal tests, modal vibration tests, and other checkout activities. This report lists the test conditions achieved and the types of data acquired and saved in the database.

NFAC↗
DOE OSTI2019

Improved learning from data competitions through strategic design of training and test data sets

Leveraging the depth and breadth of solutions generated through crowdsourcing can be a powerful accelerator to method development for high consequence problems. While data science competitions have become quite popular and prevalent, particularly in supervised learning formats, their implementations by the host are highly variable. Without careful planning, a supervised learning competition is vulnerable to overfitting, where the winning solutions are so closely tuned to the particular set of provided data that they cannot generalize to the general underlying problem of interest to the host. This paper outlines important considerations for strategically designing relevant and informative data sets to maximize the learning outcome from hosting a competition. These include: precisely defining the scope of the problem, encouraging participation by competitors from diverse technical backgrounds, specifying the most interesting solution space in order to encourage improvement and distinguish between competitors, strategically generating data sets that enable testing for interpolation and extrapolation to new scenarios of interest, leveraging design of experiment principles for strategic data design while preventing unintentional artifacts in the competition data set that an algorithm could exploit without addressing the real problem of interest, and carefully designing the leaderboard scoring metric to select top solutions that exactly match the overall competition goals. The methods are illustrated with a recently completed competition in the context of urban radiological search to evaluate algorithms capable of detecting, identifying, and locating radioactive materials. Simulated data were used in the urban search competition. Ideas for using measured real data in competitions are also suggested

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1989

Characterization of structural connections using free and forced response test data

The accurate prediction of system dynamic response often has been limited by deficiencies in existing capabilities to characterize connections adequately. Connections between structural components often are complex mechanically, and difficult to accurately model analytically. Improved analytical models for connections are needed to improve system dynamic preditions. A procedure for identifying physical connection properties from free and forced response test data is developed, then verified utilizing a system having both a linear and nonlinear connection. Connection properties are computed in terms of physical parameters so that the physical characteristics of the connections can better be understood, in addition to providing improved input for the system model. The identification procedure is applicable to multi-degree of freedom systems, and does not require that the test data be measured directly at the connection locations.

Lawrence, Charles↗
NASA NTRS1989

Characterization of structural connections using free and forced response test data

The accurate prediction of system dynamic response often has been limited by deficiencies in existing capabilities to characterize connections adequately. Connections between structural components often are complex mechanically, and difficult to accurately model analytically. Improved analytical models for connections are needed to improve system dynamic predictions. A procedure for identifying physical connection properties from free and forced response test data is developed, then verified utilizing a system having both a linear and nonlinear connection. Connection properties are computed in terms of physical parameters so that the physical characteristics of the connections can better be understood, in addition to providing improved input for the system model. The identification procedure is applicable to multi-degree of freedom systems, and does not require that the test data be measured directly at the connection locations.

Lawrence, C.↗
DOE OSTI2024

Utah FORGE: Wells 16A(78)-32 and 16B(78)-32 Extended Circulation Test Data - August and September 2024

The dataset includes data collected during an extended circulation test conducted at the Utah FORGE site between August 8 and September 5, 2024. It provides uncorrected, raw digital data from the test, along with calibration information and a final report detailing the test procedures and corrections. The data is bundled in a single .zip file containing both field calibration and test data. Files include manual calibration data for temperature, pressure, and flow meters, as well as uncorrected, time-stamped measurements recorded in 30-second intervals, such as wellhead pressures, flow rates, and temperatures for wells 16A(78)-32 and 16B(78)-32. Additionally, the final report offers insights into the test methodology and provides guidelines on how to apply field calibrations to correct the raw Pason data.

15 GEOTHERMAL ENERGY↗
NASA NTRS1993

Analysis of large system black box verification test data

Issues regarding black box, large systems verification are explored. It begins by collecting data from several testing teams. An integrated database containing test, fault, repair, and source file information is generated. Intuitive effectiveness measures are generated using conventional black box testing results analysis methods. Conventional analysts methods indicate that the testing was effective in the sense that as more tests were run, more faults were found. Average behavior and individual data points are analyzed. The data is categorized and average behavior shows a very wide variation in number of tests run and in pass rates (pass rates ranged from 71 percent to 98 percent). The 'white box' data contained in the integrated database is studied in detail. Conservative measures of effectiveness are discussed. Testing efficiency (ratio of repairs to number of tests) is measured at 3 percent, fault record effectiveness (ratio of repairs to fault records) is measured at 55 percent, and test script redundancy (ratio of number of failed tests to minimum number of tests needed to find the faults) ranges from 4.2 to 15.8. Error prone source files and subsystems are identified. A correlational mapping of test functional area to product subsystem is completed. A new adaptive testing process based on real-time generation of the integrated database is proposed.

Clapp, Kenneth C.↗