Robust design of a fan rotor blade by sweep and lean optimization with surface roughness

Abstract

In order to reduce the fan rotor aerodynamic performance degradation caused by the increasing of blade surface roughness, optimal design of high bypass ratio fan rotor blade with surface roughness was carried out to improve the aerodynamic performance of the fan rotor in long-term flight operation. With the condition of surface roughness uniformly distributed on the blade, the fan blade was optimized by using sweep and lean technology, and the aerodynamic characteristics of the fan blade with different surface roughness were numerically investigated. Numerical results show that the overall aerodynamic performance of the fan rotor decreases as the equivalent sand roughness k s of the blade increasing from 3 μm to 150 μm. The isentropic efficiency of the original blade decreases by 1.56% when the surface roughness reaches 150 μm. Composite sweep and lean optimization was carried out when k s = 80 μm, the isentropic efficiency of the optimized blade at design point is increased by 0.28%, the second optimization based on the optimized blade above by using the reverse lean technology further improved the fan isentropic efficiency by 0.12%, the degradation caused by surface roughness was reduced by optimization, and the robust design of fan rotor blade was achieved.