Aerospace medicine and biology - a continuing bibliography

Aerospace medicine and biology - bibliograph

An experimental study of labyrinth seal flow

The leakage flow in a stationary stepped labyrinth seal is investigated by means of flow visualization, pressure field measurements and Particle Image Velocimetry (PIV). The basis of the investigation is a generic stepped labyrinth seal currently used by the Tennessee Valley Authority (TVA) in their steam turbine generators. Geometric and flow parameters were varied in order to examine their influence on leakage through the seal. Following a brief theoretical development that details the physical mechanisms that cause flow energy loss and therefore leakage reduction in a single orifice, the discussion is extended to cover tire current theory describing labyrinth seals. Flow visualization results are presented for the baseline configuration, which was tested as a ten times scale water tunnel model at three different axial step locations. The observations made during these tests confirm the basic mechanisms of energy loss in labyrinth seals including turbulence induced viscous losses, chamber vortex generation, flow stagnation and increased flow streamline curvature. A 5 times scale 2-D airflow measurement stepped labyrinth seal model was constructed and tested over a range of seal pressure ratios from 1:1 to 10:1. Tested model configurations included the baseline stepped labyrinth seal and six additional variants of this basic design that were obtained by varying step height and knife angle. Results show that with relatively minor changes in geometry based on the physics of the flow through the seal, leakage reductions of up to 17% can be achieved. Finally, PIV measurements were carried out on the 2-D airflow seal models including both the five times scale baseline seal model and the improved design seal five times scale model which incorporates an increased step height and inclined long knives. Results show that the reduced leakage occurs due to an increased amount of flow stagnation and streamline curvature within the improved seal

Missouri S&T Magazine Spring 2002

https://scholarsmine.mst.edu/alumni-magazine/1061/thumbnail.jp

Missouri S&T Magazine Spring 2002

https://scholarsmine.mst.edu/alumni-magazine/1061/thumbnail.jp

Aeronautical engineering: A continuing bibliography with indexes (supplement 119)

This bibliography lists 341 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1980. Abstracts on the engineering and theoretical aspects of design, construction, evaluation, testing, operation, and performance of aircraft (including aircraft engines) and associated components, equipment, and systems are presented. Research and development in aerodynamics, aeronautics, and ground support equipment for aeronautical vehicles are also presented

A 94/183 GHz multichannel radiometer for Convair flights

A multichannel 94/183 GHz radiometer was designed, built, and installed on the NASA Convair 990 research aircraft to take data for hurricane penetration flights, SEASAT-A underflights for measuring rain and water vapor, and Nimbus-G underflights for new sea ice signatures and sea surface temperature data (94 GHz only). The radiometer utilized IF frequencies of 1, 5, and 8.75 GHz about the peak of the atmospheric water vapor absorption line, centered at 183.3 GHz, to gather data needed to determine the shape of the water molecule line. Another portion of the radiometer operated at 94 GHz and obtained data on the sea brightness temperature, sea ice signatures, and on areas of rain near the ocean surface. The radiometer used a multiple lens antenna/temperature calibration technique using 3 lenses and corrugated feed horns at 94 GHz and 183 GHz. Alignment of the feed beams at 94 GHz and 183 GHz was accomplished using a 45 deg oriented reflecting surface which permitted simultaneous viewing of the feeds on alternate cycles of the chopping intervals

STS-8 bet results

The final Best Estimate Trajectory (BET) products, i.e., the reconstructed trajectory, the Extended BET, AEROBET and MMLE input files, generated for the eighth NASA Space Shuttle flight are documented. The reconstructed trajectory (inertial BET) for this Challenger flight, the first night landing is discussed. State (position, velocity, and attitude) plus three accelerometer scale factors were determined from fitting the Guam S-band data, seven C-band passes, and pseudo Doppler and altimeter during rollout on Runway 22. The anchor epoch utilized for the batch weighted-least-squares determination was Sept. 5, 1983 7h1m50s.0 (25310 GMT seconds). The spacecraft altitude at epoch is approx. 617 kft. IMU2 data were selected for the reconstruction

Missouri S&T Magazine Spring 2003

https://scholarsmine.mst.edu/alumni-magazine/1057/thumbnail.jp

Development of a thermal and structural model for a NASTRAN finite-element analysis of a hypersonic wing test structure

The development of a thermal and structural model for a hypersonic wing test structure using the NASTRAN finite-element method as its primary analytical tool is described. A detailed analysis was defined to obtain the temperature and thermal stress distribution in the whole wing as well as the five upper and lower root panels. During the development of the models, it was found that the thermal application of NASTRAN and the VIEW program, used for the generation of the radiation exchange coefficients, were definicent. Although for most of these deficiencies solutions could be found, the existence of one particular deficiency in the current thermal model prevented the final computation of the temperature distributions. A SPAR analysis of a single bay of the wing, using data converted from the original NASTRAN model, indicates that local temperature-time distributions can be obtained with good agreement with the test data. The conversion of the NASTRAN thermal model into a SPAR model is recommended to meet the immediate goal of obtaining an accurate thermal stress distribution

Aeronautical Engineering: A cumulative index to the 1980 issue

This bibliography is a cumulative index to reports, articles, and other documents introduced into the NASA scientific and technical information system. Abstracts for the entries cited appeared in issues 119 through 130 of Aeronautical Engineering: A Continuing Bibliography (NASA SP-7037). Subject, personal author, corporate author, contract number, and report/accession number indexes are provided