Design Optimization of a Novel Flush Boundary Layer Diverter

Abstract

A novel boundary layer diverter is designed and optimized for increasing the performance of a typical semi- submerged inlet ingesting large amounts of boundary layer flow. A conceptual diverter configuration based on the prior optimization study is first parametrized with 7 design variables. A response surface model is constructed for the pressure recovery at the AIP. The flow fields over the diverter and through the inlet duct are computed with SU2 and a baseline diverter is constructed from the response surface model for maximum pressure recovery. The baseline diverter is then placed in a free-form deformation box and shape-optimized using the adjoint solver of SU2 with hundreds of design parameters. The optimum configuration provides 2.4% and 7.93% increase in the pressure recovery and the mass flow rate, respectively together with a significant reduction in flow distortion. The novel diverter is then shape-optimized together with the inlet duct. Together with all the performance parameters the pressure recovery is improved by more than 3%. It is shown that the novel boundary layer diverter by being flush to the inlet surface induces a much smaller drag compared to the conventional diverters.