Incompressible Viscous Flow Analysis of Axial Compressor Blade Cascade.

Abstract

In the present work, incompressible high Reynold's number flows around a compressor blade cascade at low speeds (Mach number 0.25) are analyzed by solving the N-S equations using the finite difference method. A generalized coordinate system is used so that a sufficient number of grid points are distributed in the boundary layer and in the wake region. A third-order upwind scheme is used for the convective term, which suppresses the non-linear instability for calculation of the high Reynold's number flow used in the present computation. The experimental-flow Reynold's number defined on the basis of blade chord length and cascade inlet velocity is 7×105. Grid topology is thought to be as important as flow solver, therefore calculations are carried out using H-type and C type grids and the results of the calculations are compared with the experimental data obtained for a controlled diffusion-type axial compressor rotor blade cascade for three different inlet flow conditions, which included design and off-design conditions. The study led to a clear understanding of the importance of the grid topology on the prediction of experimental flow behavior.