Optimization of fan rotor blade in high bypass ratio turbofan engine

By using sweep design technique, the fan rotor blade of a high bypass ratio turbofan engine was optimized in three-dimensional configuration. The influence of the sweep design parameters at blade tip and hub on the performance of the fan rotor were studied by solving three-dimensional steady Navier-Stokes (N-S) equations. The results show that both forward sweep at blade tip and backward sweep at blade hub can enhance the performance of the fan rotor, increase its chock point mass flow and enlarge its stable working range. The blade was optimized by the combined choice of forward sweep at blade tip and backward sweep at blade hub. The calculation result of the single rotor shows that the total pressure ratio and isoentropic efficiency at design mass flow point are increased 5% and 2%, respectively, and the chock point mass flow is increased about 2%. The core and bypass of fan/compressor combined calculation results show that the stable working range of the bypass is enlarged at different rotating speeds of take off, cruise and climbing state after optimization. The mass flow is increased about 2.3% at the chock point, and decreased about 5.2% at stall point at rotating speed of cruise. The total pressure ratio and isoentropic efficiency of the bypass are increased about 2% and 0.8% at design mass flow point, while the performance of the core does not change significantly after optimization.