Effect of Incoming Boundary-Layer Characteristics on Performance of a Distributed Propulsion System

Abstract

An experimental study is conducted to advance the understanding of flow physics associated with a boundary-layer ingesting, distributed propulsion system. The influence of incoming boundary-layer thickness on the performance of the system is examined. The propulsion model, integrated with electrical fans, is mounted on a flat plate and tested at subsonic speeds. Detailed characterization of the incoming boundary layer and the downstream flowfield is performed using hot-wire anemometry and static pressure measurements. Modification of the boundary layer is achieved by placing trip rods of two different diameters near the leading edge of the flat plate. Overall performance of the system is analyzed by estimating thrust, flow power, and input power to the fans. Ingestion of a thicker boundary layer is found to result in an increase in thrust and net flow power.