Aero-Propulsive Coupling of an Embedded, Distributed Propulsion System

Abstract

A computational study was conducted to study and document the aero propulsive coupling effects of a set of boundary-layer ingesting fans mounted near the trailing-edge of a wing. The fan system models a turbo electric distributed propulsion (TeDP) system such as that designed to power NASA’s NX-3 hybrid blended wing body configuration. The TeDP concept has several distinct advantages. These include boundary layer ingestion (BLI), reenergizing the wake of the airframe with the fan thrust stream, decoupling the propulsion from the power source, a very high effective bypass ratio, excellent redundancy for increased safety, and differential thrust for directional stability, trim, and possible yaw control. There are also significant challenges associated with TeDP. The TeDP concept leads to close coupling between the aerodynamics and propulsion of the airframe. Significant interactions exist between the sectional aero performance and thrust level. Changes in thrust level and mass flow through the fan affect circulation, spillage induced blockage, and stagnation point movement, producing changes in sectional lift and moment. This paper discusses a computational investigation into the aero-propulsive coupling effects on a multi-fan subscale model.