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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 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Combustion of LOX with H2(sub g) under subcritical, critical, and supercritical conditions (Task 1) and experimental observation of dense spray and mixing of impinging jets (Task 2)

The objective was to achieve a better understanding of the combustion processes of liquid oxygen and gaseous hydrogen under broad range of pressure covering subcritical, critical, and supercritical conditions. The scope of the experimental work falls into the following areas: (1) design of the overall experimental setup; (2) modification of an existing windowed high pressure chamber; (3) design of the LOX feeding system; (4) provision of the safety features in the test rig design; (5) LOX cleanliness requirements; (6) cold shock testing; (7) implementation of data acquisition systems; (8) preliminary tests for system checkout; (9) modification of LOX feeding system; and (10) evaporation tests. Progress in each area is discussed.

Kuo, K. K.↗
NASA NTRS1992

Response of a piezoelectric pressure transducer to IR laser beam impingement

The non-pressure response of a PCB Model 113A transducer to a far infrared radiation impulse from a carbon dioxide laser was investigated. Incident radiation was applied both to the bare transducer diaphragm and to coated diaphragms. Coatings included two common ablative materials and a reflective gold coating. High-flux radiation impulses induced an immediate brief negative output followed by a longer-duration positive output. Both timing and amplitude of the responses will be discussed, and the effects of coatings will be compared. Bursts of blackbody radiation from a 1500 K source produced qualitatively similar responses.

Smith, William C.↗
NASA NTRS1991

Evaluation of dual flow thrust vectored nozzles with exhaust stream impingement

The main objective of this project was to predict the expansion wave/oblique shock wave structure in an under-expanded jet expanding from a convergent nozzle. The shock structure was predicted by combining the calculated curvature of the free pressure boundary with principles and governing equations relating to oblique shock wave and expansion wave interaction. The procedure was then continued until the shock pattern repeated itself. A mathematical model was then formulated and written in FORTRAN to calculate the oblique shock/expansion wave structure within the jet. In order to study shock waves in expanding jets, Schlieren photography, a form of flow visualization, was employed. Thirty-six Schlieren photographs of jets from both a straight and 15 degree nozzle were taken. An iterative procedure was developed to calculate the shock structure within the jet and predict the non-dimensional values of Prandtl primary wavelength (w/rn), distance to Mach Disc (Ld) and Mach Disc radius (rd). These values were then compared to measurements taken from Schlieren photographs and experimental results. The results agreed closely to measurements from Schlieren photographs and previously obtained data. This method provides excellent results for pressure ratios below that at which a Mach Disc first forms. Calculated values of non-dimensional distance to the Mach Disc (Ld) agreed closely to values measured from Schlieren photographs and published data. The calculated values of non-dimensional Mach Disc radius (rd), however, deviated from published data by as much as 25 percent at certain pressure ratios.

Carpenter, Thomas W.↗
NASA NTRS1992

Evaluation of dual flow thrust vector nozzles with exhaust stream impingement

To supplement previous work performed by NASA, a cold-jet facility was established at the California Polytechnic State University, San Luis Obispo campus. The purpose of this facility is to continue the studies of cold flow multiaxis thrust vectoring conducted at the NASA Langley Research Center. A single nozzle test apparatus was completed and is presently operational. Included are the results of the single flow test envelope that was requested by NASA personnel. Details about the test apparatus are included in the Cal Poly Semi-Annual Progress report.

Carpenter, Thomas W.↗
NASA NTRS1996

Experimental Study of Liquid Jet Impingement in Microgravity: The Hydraulic Jump

A preliminary study of the Circular Hydraulic Jump (CHJ) in microgravity is reported using water as the working fluid. The evolution of the CHJ radius was measured during a sudden transition from normal to microgravity in a drop tower. The downstream height of the CHJ was controlled by submerging the target plate in a tank filled with water to the desired depth, and the measurements are compared with an existing theory for the location of the CHJ. Results showed that the CHJ diameter was larger in microgravity than normal gravity. The adjustment of the CHJ diameter to a sudden change in gravity occurred over a period of about 200 ms for the conditions of the present study, and remained constant thereafter. For flow conditions that a CHJ was not first established at normal gravity but which later appeared during the transition to microgravity, the CHJ diameter was not constant during the period of microgravity but continually changed. Good agreement between the measured and predicted CHJ diameter was found for the normal gravity data, but comparatively poorer agreement was observed for the microgravity measurements.

Avedisian, C. T.↗