Accession Number : ADA194562

Title :   Radial Mixing in Turbomachines.

Descriptive Note : Final scientific rept. 1 Sep 85-31 Aug 87,

Corporate Author : VRIJE UNIV BRUSSELS (BELGIUM) DEPT OF FLUID MECHANICS

Personal Author(s) : Deruyck, J ; Hirsch, C

PDF Url : ADA194562

Report Date : 01 Feb 1988

Pagination or Media Count : 69

Abstract : A radial mixing calculation method is presented where both convective and turbulent mixing processes are included. The secondary flows needed for the convective mixing are derived from pitch averaged vorticity equations combined with integral methods for the 3D end-wall boundary layers, 3D profile boundary layers and 3D asymmetric wakes. The convective transport due to secondary flows is computed explicitly. The method is applied to a cascade and two single stage rotors. The three test cases show a very different secondary flow behaviour which allows the analysis of the relative importance of the different secondary flow effects. Turbulent diffusion is found to be the most important mixing mechanism, whereas convective mixing becomes significant when overall radial velocities exceed about 5% of the main velocities. The wake diffusion coefficient is found to be representative for the turbulent radial mixing and is the only empirical constant to be determined.

Descriptors :   *MIXING, *SECONDARY FLOW, *WAKE, COMPUTATIONS, CONVECTION, DIFFUSION, EQUATIONS, RADIAL VELOCITY, TRANSPORT, TURBULENCE, TURBULENT FLOW, VELOCITY, VORTICES, THREE DIMENSIONAL FLOW, BOUNDARY LAYER FLOW, WALLS, ASYMMETRY, CASCADE STRUCTURES, TURBOMACHINERY

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE