Aero-propulsion coupling effects and installation characteristics of a distributed propulsion system

Abstract

The ducted fan, as a quintessential propulsion device utilized in Distributed Electric Propulsion (DEP) aircrafts, exhibits a significant influence on the aero-propulsion coupling effects due to its installation characteristics on the wing. In this paper, we employed steady-state numerical analysis techniques in conjunction with actuator disk models and overset mesh to investigate aero-propulsion coupling effects and installation characteristics of a DEP configuration with 5 ducted fans distributed along the wing's trailing edge. We compared various conditions to the wing baseline airfoil under hover condition and cruise condition of the fan tip speed ratio λ from 1.44 to 4.32 and fan installation angle δT from 0 to 90°. The results indicate that DEP system affects the flow over the wing downstream of the maximum thickness point of the baseline airfoil profile at an installation angle of 0. A higher tip speed ratio the flow is accelerated in the upper surface region near the wing's trailing edge, whereas the low energy fluid fails to be accelerated at lower λ, instead forming a local flow blocking. With the increase of the fan installation angle, the overall system lift increases, but the thrust decreases, and both trends increase with the increase of the tip speed ratio. Specifically, the thrust provided by the distributed fans is reduced, and the inlet becomes one of the drag sources when the installation angle is high.