Abstract: To improve the comprehensive performance of volute, a parametric computational fluid dymamics model of a U-shaped fan volute with the radius of semicircle segment, the height of volute, the deviation of the center of semicircle segment from the center of impeller, and the distance from bottom surface of impeller to volute internal wall is established, which is verified by experiments. A comprehensive evaluation model of volute is established, where the weights of indexes in the model, such as volume of volute, power consumption of cooling fan, and 1/air mass flow rate, are calculated with entropy method. The volute is optimized using response surface method by taking the comprehensive evaluation value as objective function. The results show that the radius R of semicircle section and the height H of volute are the main factors affecting the comprehensive evaluation function. With the increase in H and R, the comprehensive evaluation function decreases firstly and then increases. After optimizing, the comprehensive evaluation function value of volute is reduced by 23.43%, of which the performance is improved significantly. The research shows the proposed method can be used for the optimization design of volute of cooling fan.

Key words: ordnance scicne and technooogy, volute of cooling fan, comprehensive evaluation function, multi-parameter optimization, response surface method