为满足混动化后整车冷却系统对风扇性能升级的需求，提出了加大扇叶下沉量和优化扇叶叶型的优化方案，以限制扇叶叶顶间隙的涡流损失。通过CFD和CAE软件联合仿真，解析了冷却风扇微观流场，优化了扇叶结构，并预测了优化效果。试验验证表明：优化方案能有效减小叶顶间隙，抑制叶顶间隙产生的涡流损失，从而提升冷却风扇的有效风量；结合整车风阻曲线可知，优化方案可使整车实际风量增加3.3%，验证了优化方案有效性。

In order to meet the demand for upgrading the fan performance of vehicle cooling system after hybridization, a scheme to increase the downward displacement of fan blades and optimize the fan blade airfoil shape was put forward to limit the eddy current loss at the blade tip clearance. By using CFD and CAE software, the microscopic flow field of cooling fan was analyzed, the fan blade structure was optimized, and the optimization effect was predicted. Experimental verification shows that the optimization scheme can effectively reduce the blade top gap, inhibit the eddy current loss generated by the blade top gap, and hence improve the effective airflow of cooling fan. Combined with the wind resistance curve of whole vehicle, the optimization scheme can increase the actual airflow of whole vehicle by 3.3%, which verifies the validity of optimization scheme.