Accession Number : ADA307699

Title :   Supersonic Mixing Enhancement Using Pulsed Transverse Fuel Jets.

Descriptive Note : Final rept. 1 Mar 89-30 Sep 94,

Corporate Author : TENNESSEE UNIV SPACE INST TULLAHOMA

Personal Author(s) : Vakili, Ahmad D. ; Chang, Y. K. ; Wu, J. M.

PDF Url : ADA307699

Report Date : AUG 1995

Pagination or Media Count : 70

Abstract : Pulsed jets have been shown to penetrate into a cross flow more than a corresponding steady state jet. The increased penetration depends to some extent on the formation of distinct ring vortices which in turn transport themselves into the cross-flow by the self induced velocity. This work has been concentrated in understanding the physics of the increased penetration. Experiments have indicated the formation of vortex rings as a jet was pulsed even when the propane fuel was combusting. The dynamics and trajectories of vortex rings formed by pulsation of a jet in a uniform cross-flow were studied and detailed measurements were made using flow visualization techniques including laser induced fluorescence and hot-film anemometry. Measurements indicated that vortex rings were fully-formed at a distance of three times the jet exit diameter. A numerical experiment based on a Lagrangian, grid-free, three-dimensional vortex method was performed and general agreement with the experiments was concluded. At low frequencies, interaction between adjacent vortex rings was negligible because of relatively large separation distances and under these conditions, each ring behaves like a single discrete vortex ring. It was observed that single vortex rings moved into the flow sometimes tilted up to about 30 degrees, depending on the ring's strength, etc.

Descriptors :   *VORTICES, *SUPERSONIC FLOW, *CROSS FLOW, *JET MIXING FLOW, VELOCITY, COMPUTERIZED SIMULATION, OPTIMIZATION, LASER INDUCED FLUORESCENCE, COMPUTATIONAL FLUID DYNAMICS, FLOW VISUALIZATION, FLOW FIELDS, PENETRATION, DATA ACQUISITION, PARTIAL DIFFERENTIAL EQUATIONS, UNSTEADY FLOW, INVISCID FLOW, JET ENGINE FUELS, VISCOSITY, FLOW SEPARATION, REYNOLDS NUMBER, INCOMPRESSIBLE FLOW, HOT WIRE ANEMOMETERS, PROPANE, SHOCK TUBES, LAGRANGIAN FUNCTIONS, STEADY FLOW, FUEL INJECTION, THREE DIMENSIONAL FLOW, PULSEJET ENGINES, STROUHAL NUMBER.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE