Accession Number : ADA311717

Title :   Three-Component Velocity Measurements Downstream of a Bluff-Body Flameholder.

Descriptive Note : Final rept. 1 Jun 93-1 May 95,

Corporate Author : WRIGHT LAB WRIGHT-PATTERSON AFB OH AERO PROPULSION AND POWER DIRECTORATE

Personal Author(s) : Raffoul, Charbel N. ; Nejad, Abdollah S. ; Gould, Richard D.

PDF Url : ADA311717

Report Date : OCT 1995

Pagination or Media Count : 212

Abstract : In order to enhance fuel and air mixing for more efficient combustion, it has been suggested to use bodies that generate vortical and turbulent structures in their wake. The injected fuel from the surface of in-stream mounted fuel injectors will interact with the turbulent flow and thoroughly mix with the freestream air. Simple 2-d and 3-d bluff bodies have been the subject of experimental investigations for a number of years. However, the opportunity has never before existed for the full exploration of the flowfield downstream of such bodies. The introduction of laser Doppler velocimetry (LDV) must be credited for more accurate measurements in the area of fluid mechanics in general, and in particular in the recirculating and complex flows such as the case of this study. In order to establish a baseline frame of reference for future work employing bluff bodies with vortex generators, the flow characteristics around a 2-d bluff body were experimentally investigated in this effort. Three-component velocity measurements using LDV were made in the highly turbulent flow past a 2-d bluff body. The contribution of this study is unique as all three velocity components were simultaneously measured at each point without introducing disturbances to the flow. Vertical data profiles were obtained at 11 axial stations in the far-field and at 8 axial stations in the near-field. Spanwise profiles of the flowfield immediately downstream of the bluff body were also determined. The three orthogonal mean velocities, the six Reynolds stresses and all nine turbulent triple products were estimated. The production, convection, and diffusion of turbulent kinetic energy were computed directly from the experimental data using numerical differencing.

Descriptors :   *TURBULENT FLOW, *FUEL AIR RATIO, *FLAME HOLDERS, DATA BASES, MATHEMATICAL MODELS, STRESS ANALYSIS, AIR FLOW, ACCURACY, TURBULENCE, VORTICES, COMPUTATIONAL FLUID DYNAMICS, VORTEX SHEDDING, MASS FLOW, FLOW FIELDS, THERMAL DIFFUSION, ERROR ANALYSIS, SHEAR STRESSES, KINETIC ENERGY, WAKE, TWO DIMENSIONAL FLOW, SUBSONIC FLOW, FUEL INJECTORS, CONVECTION(HEAT TRANSFER), FREE STREAM, PRESSURE DISTRIBUTION, REYNOLDS NUMBER, INCOMPRESSIBLE FLOW, LASER VELOCIMETERS, VORTEX GENERATORS, AXIAL FLOW, MOMENTUM TRANSFER, THREE DIMENSIONAL FLOW, JET MIXING FLOW.

Subject Categories : Fluid Mechanics
      Combustion and Ignition

Distribution Statement : APPROVED FOR PUBLIC RELEASE