A comprehensive analysis of flow blowing and its effects on change in main flow conditions and loss generation in compressible flows

Abstract

In this study, flow blowing into compressible main stream is analyzed using analytical models and Computational Fluid Dynamics (CFD). First, an analytical model based on the general form of equations for flow blowing into compressible main stream is presented. A loss model that provides a complete expression for total entropy generation due to flow blowing process by considering the irreversibilities in both the main stream and the blowing flow is developed next. Equations from the analytical model are solved numerically and the results obtained are used together with the loss model to demonstrate the effect of blowing angle, stagnation conditions of the blowing flow, and local Mach number in front of the blowing location on the change in the conditions of the main stream, choking mass flow rate and loss generation in terms of entropy production. Finally, results from theoretical models are checked against the solution of the Navier-Stokes equations using CFD. For subsonic flows, an excellent agreement between the theoretical results and CFD is found for up to 7% blowing mass flow rate and 90 degree blowing angle, while for supersonic flows the agreement is reasonably well for only up to 5% blowing mass rate and 90 degree blowing angle.