风冷柴油机高负荷轴流冷却风扇气动优化OA北大核心CSTPCD

For a cooling fan with negative prewhirl front stator of an air-cooled diesel engine,by considering the coupling effect of the stator and the rotor,the multi-objective aerodynamic optimization of the cooling fan was implemented based on the polynomial surrogate model and the non-dominated sorting genetic algorithm Ⅱ.The optimized efficiency and total pressure increased by 1.19% and 4.78% respectively under the near-stall condition,and increased by 0.29% and 3.16% respectively under the design condition.The key design variables were identified by Sobol's global sensitivity analysis method,and the flow mechanisms for improving the aerodynamic performances of the fan were obtained by combining the changes of the flow fields before and after optimization.The decrease of the hub blade angle of the stator and the increase of the hub blade angle of the rotor jointly reduce the angle of attack of the rotor inlet,thereby increasing the isentropic efficiency of the fan,and making up for the total pressure reduction caused by the decrease of Euler work.The tip blade angle of the rotor is reduced,which weakens the imbalance between the hub and the tip regions,and compensates for the loss of total pressure.