The matching characteristics and flow mechanisms of partial-height booster rotor and fan rotor for a high-throughflow fan

Abstract

Further enhancements in the throughflow capacity of the conventional fan in the turbofan engine are limited by its aerodynamic and geometric parameters, but the concept of a high-throughflow fan is expected to overcome this limitation. This study explored the effects of the parameters of axial overlap (AO) and percent pitch (PP) on the aerodynamic performance of a high-throughflow fan by using validated numerical simulations to clarify the complicated mechanisms of the tandem rotor. The results showed that the tandem rotor determined the overall stage performance. The isentropic efficiency and total pressure ratio of the tandem rotor reached the best as AO = +10%, and PP = 20%. When PP was small and AO changed, the stronger passage shock wave in the fan rotor (FR) was the main factor influencing the aerodynamic performance of the tandem rotor. While PP enlarged to a high level and AO changed, interactions between the tip vortex or wake and the low-energy fluids of the FR pressure surface (PS), and the strength of the passage shock wave in the FR determined the isentropic efficiency, which was slightly different from the lower PP.