Accuracy improvement of the bleed boundary condition with the effects of porosity variations and expansion waves

Abstract

The present research deals with accuracy improvement of the bleed boundary condition model that numerically simulates boundary layer bleed which is used to improve performance of supersonic inlets. Three bleed models formulated for supersonic flows are implemented and analyzed from the perspective of both the bleed mass rate and the response of the boundary layer when the flow passes through and downstream of a bleed mass flow removal region. In order to increase the accuracy of the bleed model, this study performs a scaling of the sonic flow coefficient data for 90-degree bleed holes in consideration of Prandtl-Meyer expansion theory and assumes that the porosity varies with the stream-wise location of the porous bleed plate, which distinguishes individual bleed holes. Additionally, three-dimensional CFD simulations that contain the geometric feature of the bleed plate are performed and compared with the results of bleed boundary condition models. As a result, The corrected bleed model does a reasonable agreement with experimental data and the result of three-dimensional CFD simulations.