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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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NASA NTRS1983

Langley test highlights, 1982

A 20 ft vertical spin tunnel, a 30 by 60 ft tunnel, a 7 by 10 ft high speed tunnel, a 4 by 7 meter tunnel, an 8 ft transonic pressure tunnel, a transonic dynamics tunnel, a 16 ft transonic tunnel, a national transonic facility, a 0.3 meter transonic cryogenic tunnel, a unitary plan wind tunnel, a hypersonic facilities complex, an 8 ft high temperature tunnel, an aircraft noise reduction lab, an avionics integration research lab, a DC9 full workload simulator, a transport simulator, a general aviation simulator, an advanced concepts simulator, a mission oriented terminal area simulation (MOTAS), a differential maneuvering simulator, a visual/motion simulator, a vehicle antenna test facility, an impact dynamics research facility, and a flight research facility are all reviewed.

Source record↗
NASA NTRS1983

Development of a distributed-parameter mathematical model for simulation of cryogenic wind tunnels

A one-dimensional distributed-parameter dynamic model of a cryogenic wind tunnel was developed which accounts for internal and external heat transfer, viscous momentum losses, and slotted-test-section dynamics. Boundary conditions imposed by liquid-nitrogen injection, gas venting, and the tunnel fan were included. A time-dependent numerical solution to the resultant set of partial differential equations was obtained on a CDC CYBER 203 vector-processing digital computer at a usable computational rate. Preliminary computational studies were performed by using parameters of the Langley 0.3-Meter Transonic Cryogenic Tunnel. Studies were performed by using parameters from the National Transonic Facility (NTF). The NTF wind-tunnel model was used in the design of control loops for Mach number, total temperature, and total pressure and for determining interactions between the control loops. It was employed in the application of optimal linear-regulator theory and eigenvalue-placement techniques to develop Mach number control laws.

Tripp, J. S.↗
NASA NTRS1982

Mechanical properties of adhesive systems at cryogenic and other temperatures

This paper presents a summary of the National Transonic Facility (NTF) fan blade adhesive characterization tests. Data was obtained at -300 F, room temperature (RT) and 200 F. The adhesive characterization data was acquired using specimens fabricated from materials orientated to simulate the lay up of the fan blades. Specimen fabrication, characterization tests, test equipment, test data, results and concluding remarks are reported. Adhesive test results are presented for specimens of the following types: lap shear, double lap shear, butt, short beam shear, flexure, and differential strain.

Staton, W. L.↗
NASA NTRS1984

Fracture temperature and flaw growth in nitronic 40 at cryogenic temperatures

The fracture resistance and fatigue response of Armco Nitronic 40 austenitic stainless steel were evaluated under cryogenic conditions. Tensile, fracture toughness and fatigue crack growth properties were measured at -275 F. The tensile yield strength was approximately 120 ksi and the fracture toughness was estimated to be 350 ksi-in /2 on the basis of fracture toughness measurements. Testing was conducted to evaluate the behavior of a simulated section of the wing of the Pathfinder 1 model subject to a load and temperature history typical of that for testing in the National Transonic Facility. The wing section model incorporated a proposed brazing technique for pressure-transducer attachment. The simulated wing section performed satisfactorily at stress levels of nearly 60 percent of the material yield strength. The brazing technique proved to be an effective method of transducer attachment under conditions of high stress levels and large temperature excursions.

Domack, M. S.↗
NASA NTRS1984

Evaluation tests of platinum resistance thermometers for a cryogenic wind tunnel application

Thirty-one commercially designed platinum resistance thermometers were evaluated for applicability to stagnation temperature measurements between -190 C and +65 C in the Langley Research Center's National Transonic Facility. Evaluation tests included X-ray shadowgraphs, calibrations before and after aging, and time constant measurements. Two wire-wound low thermal mass probes of a conventional design were chosen as most suitable for this cryogenic wind tunnel application.

Germain, E. F.↗
NASA NTRS1984

Cryogenic wind-tunnel model technology development activities at the NASA Langley Research Center

This paper summarizes the current cryogenic wind-tunnel model technology development activities at the NASA Langley Research Center. These research and development activities are being conducted in support of the design and fabrication of models for the new National Transonic Facility (NTF). The scope and current status of major research and development work is described and where available, data are presented from various investigations conducted to date. In addition, design and fabrication experience for existing developmental models to be tested in the NTF is discussed.

Young, C. P., Jr.↗
NASA NTRS1983

Application of laser anemometry to cryogenic wind tunnels

The installation and tests conducted with the laser Doppler and transit anemometer in the 0.3-Meter Transonic Cryogenic Tunnel are described. Using residual particulates in the flow field, a series of free stream velocity measurements were conducted which agreed to within 1-percent of predicted values for a range of Mach numbers, 0.2 to 0.85, and temperatures, 100 to 250 K. Measurements about a shock wave provided an estimate of scattering particulate size of 4 microns or less. The particle concentration is approximately 3 x 10 to the 5th to 1.6 x 10 to the 6th/cu m. Necessary isolation of the plenum wall windows from ambient air with slightly positive pressure of dry nitrogen gas to prevent condensation on the window surface was achieved. This was accomplished through the use of large enclosures fixed to the tunnel wall. A second method used an additional sheet of thin plate glass to create the dry gas pocket next to the plenum window. The installation of a laser anemometer in the National Transonic Facility is examined. The laser transit anemometer has been tentatively selected for the initial entry because of its compact laser-optics package.

Hunter, W. W., Jr.↗
NASA NTRS1984

Design of high-Reynolds-number flat-plate experiments in the NTF

The design of an experiment to measure skin friction and turbulent boundary-layer characteristics at Reynolds numbers exceeding one billion is described. The experiment will be conducted in a zero-pressure-gradient flow on a flat plate in the National Transonic Facility. The development of computational codes to analyze the aerodynamic loads and the blockage is documented. Novel instrumentationn techniques and models, designed to operate in cryogenic environments, are presented. Special problems associated with aerodynamic loads, surface finish, and hot-wire anemometers are discussed.

Saric, W. S.↗
NASA NTRS1984

Thermal analysis of cryogenic wind tunnel models

This paper summarizes the thermal analysis activity being performed in support of the design of wind tunnel models for the National Transonic Facility (NTF) at the NASA Langley Research Center. The goal of the analysis effort has been to address model design difficulties associated with the severe thermal environment of this cryogenic wind tunnel. The unique characteristics of this environment are discussed for various phases of tunnel operation. The methods used to calculate temperatures and thermal stresses in the models are also described. The results indicate that thermal considerations do not drive the design to the extent originally envisioned. In general, the problems identified are localized and associated with thermal mismatch between components. Several specific examples of thermal design problems and proposed solutions are given.

Carlson, A. B.↗
NASA NTRS1986

Connectors and Wiring for Cryogenic Temperatures

Tests performed at Langley Research Center to find connectors, cables, and other electrical components suitable for use in cryogenic environment described. In addition, several electrical cables have to flex under cryogenic conditions. Tests necessary to qualify materials for use in National Transonic Facility (NTF), which operates at temperature range from 175 degrees to - 300 degrees F (353 to 89 K).

Turner, R. D.↗
NASA NTRS1984

Stereo Electro-optical Tracking System (SETS)

The SETS is a remote, non-contacting, high-accuracy tracking system for the measurement of deflection of models in the National Transonic Facility at Langley Research Center. The system consists of four electronically scanned image dissector trackers which locate the position of Light Emitting Diodes embedded in the wing or body of aircraft models. Target location data is recorded on magnetic tape for later 3-D processing. Up to 63 targets per model may be tracked at typical rates of 1280 targets per second and to precision of 0.02mm at the target under the cold (-193 C) environment of the NTF tunnel.

Koenig, E. W.↗
NASA NTRS1985

Response time correlations for platinum resistance thermometers

The 'plunge method' recommended by ASTM has been used to determine the time constant of 100-ohm platinum resistance thermometers (PRT) considered for use in the National Transonic Facility. It is shown that the response time of ventilated PRT can be correlated with the reciprocal of the heat transfer coefficient in a given field. Universal correlations are established for the 100- and 1000-ohm PRT with uncertainties of 20 and 30 percent, respectively. The correlations are found to be consistent with the uncertainty involved in heat transfer correlations available in the literature and are recommended for use in flowing liquids and gases.

Pandey, D. K.↗
NASA NTRS1985

Mechanical behavior of 18 Ni 200 grade maraging steel at cryogenic temperatures

A comprehensive study was conducted to characterize the mechanical behavior of 18 Ni 200 grade maraging steel for cryogenic applications in the National Transonic Facility. Tensile, fatigue, impact, and fracture toughness properties were determined at room and cryogenic temperatures. Experimental variables included product form, specimen orientation, and variation in metallurgical condition accomplished with a grain refining heat treatment. Room temperature tensile yield strength was approximately 200 ksi, while the yield strength at -275 F was approximately 260 ksi. Charpy V-notch energy absorption values and fracture toughness values of 18 Ni steel were found to be dependent on temperature, product form, orientation, and metallurgical condition. Fracture toughness values ranged from 80 to 113 ksi-sq rt in. at room temperature and from 67 to 90 ksi-sq rt in. at -275 F. The results of this study indicate that 18 Ni 200 grade maraging steel exceeds the strength criterion of 150 ksi minimum yield strength for use in cryogenic wind tunnel models but is marginal with respect to the 85 ksi sq rt in fracture toughness criterion at -275 F.

Wagner, J. A.↗
NASA NTRS1985

NTF: Soldering Technology Development for Cryogenics

The advent of the National Transonic Facility (NTF) brought about a new application for an old joining method, soldering. Soldering for use at cryogenic temperatures requires that solders remain ductile and free from tin-pest (grey tin), have toughness to withstand aerodynamic loads associated with flight research, and maintain their surface finishes. Solders are used to attach 347 Stainless-Steel tubing in surface grooves of models. The solder must fill up the gap and metallurgically bound to the tubing and model. Cryogenic temperatures require that only specific materials for models can be used, including: Vasco Max 200 CVM, lescalloy A-286 Vac Arc, pH 13-8 Mo. Solders identified for testing at this time are: 50% Sn - 49.5% Pb - 0.5% Sb, 95% Sn - 5% Sb, 50% In 50% Pb, and 37.5% Sn - 37.5% Pb - 25% In. With these materials and solders, it is necessary to determine their solderability. After solderability is determined, tube/groove specimens are fabricated and stressed under cryogenic temperatures. Compatible solders are then used for acutual models.

Hall, E. T., Jr.↗
NASA NTRS1986

Evaluation of a Quartz Bourdon Pressure Gage of Wind Tunnel Mach Number Control System Application

A theoretical and experimental study was undertaken to determine the feasibility of using the National Transonic Facility's high accuracy Mach number measurement system as part of a closed loop Mach number control system. The theoretical and experimental procedures described are applicable to the engineering design of pressure control systems. The results show that the dynamic response characteristics of the NTF Mach number gage (a Ruska DDR-6000 quartz absolute pressure gage) coupled to a typical length of pressure tubing were only marginally acceptable within a limited range of the facility's total pressure envelope and could not be used in the Mach number control system.

Chapin, W. G.↗
NASA NTRS1986

Effect of Reynolds Number and Mach Number on flow angularity probe sensitivity

Preliminary calibrations were performed on nine flow angularity probes in the Langley 7- by 10-Foot High-Speed Tunnel (7 x 10 HST) and the Langley 0.3-Meter Transonic Cryogenic Tunnel (0.3-m TCT). These probes will be used in surveying the test section flows of the National Transonic Facility (NTF). The probes used in this study have a pyramid head with five pressure orifices. The calibrations consisted of both isolated probe measurements and rake-mounted multiprobe measurements that covered a range of subsonic Mach numbers up to 0.90 and Reynolds numbers per foot up to 40 X 10 to the 6th power. The preliminary calibration in the 7 x 10 HST included testing the probes both individually and in a rake. The 0.3-m TCT calibration tested two probes singly at varying Reynolds numbers. The results from these tests include Mach number, Reynolds number, and rake-mounting effects. The results of these tests showed probe sensitivity to be slightly affected by Mach number. At Reynolds numbers per foot above 10 x 10 to the 6th power, the probe did not exhibit a Reynolds number sensitivity.

Smith, L. A.↗
NASA NTRS1986

Surface roughness studies for wind tunnel models used in high Reynolds number testing

This paper focuses on stylus and optical techniques for the measurement of surface roughness in wind tunnel models. The stylus instruments provide detailed information, such as surface profiles and area maps, that may then be used either to calculate statistical properties (i.e., the rms surface roughness) or to study individual surface peaks or other features. By contrast, certain optical techniques yield area-averaged statistical properties of the surface roughness directly. Two instruments that use the technique of optical angular scattering are compared. One is a research instrument that has been developed to study the basic scattering phenomena by testing the optical theories and surface models used in inverse calculations of statistical roughness parameters. The second instrument is more compact and is under development as a hand held, on-line device to be used during manufacture of wind tunnel models for the National Transonic Facility at NASA Langley Research Center. The scattering geometries for the two instruments are compared and results from these instruments and the stylus technique are shown for roughness specimens that are typical of the surface finish of wind tunnel models.

Vorburger, T. V.↗
NASA NTRS1985

Model deformation measurements at a cryogenic wind tunnel using photogrammetry

A photogrammetric closed circuit television system to measure model deformation at the National Transonic Facility (NTF) is described. The photogrammetric approach was chosen because of its inherent rapid data recording of the entire object field. Video cameras are used to acquire data instead of film cameras due to the inaccessibility of cameras which must be housed within the cryogenic, high pressure plenum of this facility. Data reduction procedures and the results of tunnel tests at the NTF are presented.

Burner, A. W.↗