Modeling the Effect of Stability Bleed on Back-Pressure in Mixed-Compression Supersonic Inlets

Abstract

To stabilize the terminal normal shock on high-static pressure at outlet, called back-pressure pout, stability bleed slots are used in the throat of mixed-compression supersonic inlets. In this paper, a model for the functional relation between the bleed flow rate mbl and back-pressure pout is established based on a bleed flow rate model (BFRM) in order to study the effect of stability bleed on the back-pressure in mixed-compression supersonic inlets. Given the inlet flow parameters Min, pin*, and Tin*, the plenum pressure ppl at slots' outlet, the terminal normal shock position xs in this model, the bleed flow rate mbl, Mach number M¯out, and back-pressure pout were derived one by one from the basic laws of conservation. To study the effect of plenum pressure ppl on subsonic flow of the divergent section behind the terminal normal shock, a correction coefficient κ is introduced to modify the Mach number M¯out. Furthermore, numerical simulations based on Reynolds-Averaged Navier–Stokes equations were performed to analyze the functional relation between the bleed flow rate mbl and back-pressure pout. Computational fluid dynamics (CFD) results show that the present model agrees with the data.