Numerical Study of Ducted-fan Lip Stall Suppression Based on Inflatable Leading Lip Cell

A novel method using inflatable leading lip cell for suppressing duct lip stall of ducted fan system is presented and numerically simulated using unsteady Reynolds-averaged Navier-Stokes equations. The lip inflatable mechanism consists of an inflatable cell and a faring cell. The inflatable cell size is controllable via inflating or deflating, while the faring cell is basically used to help form a desirable shape of a smooth configuration. The inflatable cell can change the shape of the duct lip, resulting in the change of flow pattern around the duct lip. This method has advantages of no rotating or transmission mechanism, minimum change to the original duct structure, and maximum shape control range. Preliminary results of the numerical simulation demonstrate that the method presented is effective in suppressing the duct lip stall, and it is a promising applicable stall suppression approach.