Numerical Investigations of Fan-in-Wing Aerodynamic Performance with Active Flow Control

Abstract

Aerodynamic performance of a fan-in-wing configuration in hover is numerically investigated using a high-fidelity three-dimensional unsteady Reynolds-averaged Navier–Stokes flow solver based on unstructured grid technology. Fan-in-wing or ducted fan configurations offer the advantage of hover capability with enhanced thrust comparing to open fans, but they suffer from reduced efficiency and thrust levels at offdesign conditions. In this study, the aerodynamic performance and flowfield of a fan-in-wing configuration in hover are numerically investigated over a range of blade pitch angles at two operating speeds. The maximum thrust, peak efficiency, and stall margin of the system are among the main interests of this investigation. An innovative concept using an active flow control is introduced in this study to enhance the operating efficiency and thrust level of the system by increasing the circulation and duct mass flow rate in the fan-in-wing system. Numerical investigations indicate a 25–55% increase in the maximum system thrust, achieved without suffering the peak efficiency loss, when using the proposed active flow control concept. This potentially provides a viable technology to significantly enhance the aerodynamic performance of lift fan devices such as the ducted fans or fan-in-wing configurations to support the research of vertical takeoff and landing aircraft.