Aerodynamic optimization method for duct design

Based on momentum source method of calculating the ducted fan aerodynamic performance, the response surface method and neural network method were applied to aerodynamic optimization design of the NASA duct, and the optimization results were verified by CFD method. The optimization design results show that the two methods have achieved good effect. In the state of hovering, compared with the original duct, duct lift increased by 19.4% based on the response surface method, and duct lift increased by 21.2% based on the neural network method. In addition, in order to study the mechanism of duct lift more carefully, the duct was modeled, and partitioning method was adopted to divide the duct into 6 zones to obtain the duct lift distribution in the 6 regions. This shows that negative pressure formed on duct lip is a main factor to produce additional duct lift, and the duct lip near the interior duct provides higher lift. This optimization method can be effectively applied to the ducted fan aerodynamic optimization design.