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.

Design Factors of High- speed Turbo-electric Distributed Propulsion System

“…TeDP systems are based on electricity generation through a directly-coupled gas-turbine-electric-generator and distribute propulsive power through small electrical motors located in aircraft wings and tips [8], known as Distributed Electric Propulsion (DEP). The coupling between the aircraft's propulsion system and its airframe creates a Boundary Layer Ingestion (BLI), allowing the propulsion system to ingest and re-energize a portion of the boundary layer created on the body of the aircraft [9,10]. The combined effect of DEP and BLI increases the propulsive efficiency of the aircraft and lift while reducing the drag, power, and fuel consumption [9,10].…”

“…The coupling between the aircraft's propulsion system and its airframe creates a Boundary Layer Ingestion (BLI), allowing the propulsion system to ingest and re-energize a portion of the boundary layer created on the body of the aircraft [9,10]. The combined effect of DEP and BLI increases the propulsive efficiency of the aircraft and lift while reducing the drag, power, and fuel consumption [9,10].…”