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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 469 records · Page 26

Results of convective heating tests of a longitudinal gap on the Rockwell flat plate model (15-0, insert 7) in the NASA/Ames Research Center

Results are presented which were obtained from tests in a hypersonic wind tunnel to determine aerodynamic heating rates in a gap running parallel or slightly askew to the flow direction. The model used was a flat plate instrumented in thin-skin sections with chromelconstantan thermocouples. Heating rate profiles lengthwise along and down into the gap were obtained, and additional data were obtained from a total temperature probe and rake fabricated during the test to investigate an apparent aerodynamic cooling trend in the gap. Model variables were width, depth, length, and orientation of the gap relative to the flow direction. The tests were conducted at Mach 5.1 and Reynolds numbers per foot of 500,000, 1,000,000, and 2,000,000.

Quan, M.↗

Mixing insert for foam dispensing apparatus

A device for mixing foam ingredients is described. The device comprises an arrangement of lands situated about a cylindrical elongated shaft-like member with each land having a slot. The slots of alternate lands are positioned 180 deg from each other so that as the ingredients flow through the mixing chamber they flow from adjacent one side of the housing to the other dividing as such passes around the shaft-like member.

Simpson, W. G.↗

Low-insertion-resistance current monitor

Circuit automatically corrects for drifting offset voltage, providing long-term stability for current-monitoring instruments. Circuit is stable over wide temperature range; therefore, no compensation for temperature variations is necessary. Besides consuming little power, circuit introduces negligible noise on monitored lines and responds linearly to monitored circuit.

Paulkovich, J.↗

An interplanetary targeting and orbit insertion maneuver design technique

The paper describes a tradeoff in selecting a planetary encounter aimpoint and a spacecraft propulsive maneuver strategy in the Pioneer Venus Orbiter Mission. The method uses parametric data spanning a region of acceptable targeting aimpoints in the delivery space and the geometric considerations. Real-time maneuver adjustments accounted for known attitude control errors, orbit determination updates, and late changes in a targeting specification.

Hintz, G. R.↗

Analysis and design of a ceramic nozzle insert for the Langley 8-foot high temperature structures tunnel

An analysis is presented of various ceramic design concepts intended to improve nozzle throat life and tunnel performance in the hypersonic Langley 8-Foot High-Temperature Structures Tunnel, which uses methane-air combustion products as the wind-tunnel test medium. Calculations of the axial pressure distribution and heating rates in the air-cooled nozzle throat are presented, and desirable characteristics of a ceramic material to be used in the nozzle throat are outlined, including high-temperature strength, thermal shock and erosion resistance, low conductivity and low thermal expansion. Ceramic nozzle throat design concepts are then examined, with attention given to monolithic and layered constructions of cast ceramics, reaction-bonded materials and a fiber-reinforced silica-silica ceramic. Results of a finite element analysis of the temperatures and stresses characteristic of the various concepts are then presented which indicate the monolithic silica-silica and the layered silica-silica/reaction bonded silicon nitride concepts to be the most promising of those investigated.

Robinson, J. C.↗

Bolt Inserts for Lightning Protection

Stainless steel bolt fasteners have adequate grounding paths for protection of structures against lightning strikes. Fasteners particularly useful in sections where insulating material required, such as thermal panels of external storage tank.

Hambrock, K. O.↗

Computation of imaginary-side pressure distributions over the flexible walls of the test section insert for the 0.3-M transonic cryogenic tunnel

Two dimensional airfoil testing in an adaptive wall test-section wind tunnel requires the computation of the imaginary flow fields extending outward from the top and bottom test section walls. A computer program was developed to compute the flow field which would be associated with an arbitrary test section wall shape. The program is based on incompressible flow theory with a Prandtl-Glauert compressibility correction. The program was validated by comparing the streamline and the pressure field generated by a source in uniform flow with the results from the computer program. A listing of the program, the validation test results, and a sample program are included.

Goodyer, M. J.↗

Pin Inserts for Plug Welds

Leakage through minute cracks eliminated. Electron-beam-welded pins reinforce material around coolant holes during plug welding and subsequent remachining. Pins removed in final machining of 0.188-in diameter hole.

Penninger, Michael↗

Ca + HF - The anatomy of a chemical insertion reaction

A comprehensive first-principles theoretical investigation of the gas phase reaction Ca + HF - CaF + H is reported. Ab initio potential energy calculations are first discussed, along with characteristics of the computed potential energy surface. Next, the fitting of the computed potential energy points to a suitable analytical functional form is described, and maps of the fitted potential surface are displayed. The methodology and results of a classical trajectory calculation utilizing the fitted potential surface are presented. Finally, the significance of the trajectory study results is discussed, and generalizations concerning dynamical aspects of Ca + HF scattering are drawn.

Jaffe, R. L.↗

Automatic computation of wing-fuselage intersection lines and fillet inserts with fixed-area constraint

Procedures for automatic computation of wing-fuselage juncture geometry are described. These procedures begin with a geometry in wave-drag format. First, an intersection line is computed by extrapolating the wing to the fuselage. Then two types of filleting procedures are described, both of which utilize a combination of analytical and numerical techniques appropriate for automatic calculation. An analytical technique for estimating the added volume due to the fillet is derived, and an iterative procedure for revising the fuselage to compensate for this additional volume is given. Sample results are included in graphical form.

Barger, Raymond L.↗

ELITE Program: Electric Insertion Transfer Experiment

The topics are presented in viewgraph form and include the following: the Cooperative Research & Development Agreement (CRDA); spacecraft; benefits; program milestones; subsystem status; partners; and payloads.

Vondra, Robert↗

Investigation of advanced fault insertion and simulator methods

The cooperative agreement partly supported research leading to the open-literature publication cited. Additional efforts under the agreement included research into fault modeling of semiconductor devices. Results of this research are presented in this report which is summarized in the following paragraphs. As a result of the cited research, it appears that semiconductor failure mechanism data is abundant but of little use in developing pin-level device models. Failure mode data on the other hand does exist but is too sparse to be of any statistical use in developing fault models. What is significant in the failure mode data is that, unlike classical logic, MSI and LSI devices do exhibit more than 'stuck-at' and open/short failure modes. Specifically they are dominated by parametric failures and functional anomalies that can include intermittent faults and multiple-pin failures. The report discusses methods of developing composite pin-level models based on extrapolation of semiconductor device failure mechanisms, failure modes, results of temperature stress testing and functional modeling. Limitations of this model particularly with regard to determination of fault detection coverage and latency time measurement are discussed. Indicated research directions are presented.

Dunn, W. R.↗