Investigation on effect of S-shaped inlet distortion to rear fan stage aerodynamic performance

For the sake of investigating impact of inlet distortion on the fan stage performance, the prototype and optimization of a flush-mounted S-shaped inlet was composed with the rear fan stage as whole respectively, and then numerical simulation of the two whole structure were conducted. The results show that the total pressure ratio as well as the efficiency of the fan stage decreases dramatically due to substantial boundary layer ingesting, the choked mass flow and the maximum isentropic efficiency decrease 1.20% and 3.77%, respectively. After optimization, the stable operation range is extended significantly, the choked mass flow and the isentropic efficiency peak increase about 0.19% and 0.23% separately. Under effect of rotating rotor, the significant low energy region at bottom of the inlet exit decreases ceaselessly when it developing backward to front-edge of the rotor blade, more-over, the high-energy fluid mixes with the low-energy fluid, no matter inlet optimization proceed or not.