Experimental Investigations on the Influence of Ingesting Boundary Layers into a Diverterless S‐Duct Intake

Abstract

An experimental study of the combined effects of boundary layer ingestion and an Sduct diffuser on flow conditions at the engine face is presented. A main focus of the investigations is on the impact of boundary layers on intake performance and on limitations of diverterless intakes due to boundary layer ingestion. The dependence of total pressure distortions on flow parameters has been examined in a parametric study in a blow-down wind tunnel. The free-stream Mach number was varied between M = 0.30 and M = 0.65. In order to form a boundary layer of well-defined thickness ahead of the intake the model is arranged on a flat plate. In the introduction the importance of boundary layer ingesting highly integrated intakes is briefly discussed. This is followed by a description of the analytical design of the generic intake model, the cryogenic blowdown tunnel DNW-KRG in which the experimental tests have been performed, and the measurement techniques. Thereafter, experimental findings are discussed in detail and conclusions are drawn.