Effects of power layout on aerodynamic performance of distributed electric propulsion aircraft

In order to carry out the design of distributed electric propulsion (DEP) aircraft, it is important to understand the flow mechanism and the changing law of aerodynamic comprehensive gain of DEP aircraft under strong coupling effects of the distributed power and the wing. Aiming at distributed propeller-wing layouts, the present study investigates the aerodynamic performance of DEP configurations based on the VLM-ADT (vortex lattice method - actuator disk theory) fast solver for aerodynamic characteristics. The effects of three factors, i.e., the propeller number, the rotating direction, and the propeller spacing, on the aerodynamic performance metrics such as the lift-to-drag ratio L/D, the power load T/P, and the overall efficiency L/P, are studied in particular. As the number of propellers increases, the lift-to-drag ratio decreases, but the overall efficiency increases. When the number of propellers is not larger than 5, the lift-to-drag ratio of the co-rotating configuration is greater than that of the counter-rotating configuration. When the number of propellers is 7, the lift-to-drag ratio of the counter-rotating configuration is greater than that of the co-rotating configuration. Compared to the co-rotating configuration, the lift-to-drag ratio of the counter-rotating configuration increases when the propeller disk load is increased. The distributed propellers increase the lift and drag at the same time when they are densely concentrated at the wing tip. When the wing-tip propeller is fixed at the wing tip while the other propellers are densely concentrated near the center of the wing, it has the effect of increasing the lift and reducing the drag, and the lift increase is more than that of the propeller concentrating at the wing tip.