轴流泵多目标优化正交试验

Multi-objective Optimization Design and Test of Axial-flow Pump

为了整体提高轴流泵的水力优化设计水平,找出影响轴流泵性能的主要几何参数,运用正交试验方法,以扬程、效率、轴功率和压力脉动作为试验评判指标,将综合频率分析法应用到轴流泵多目标优化设计中。基于L_9(3~4)正交表得到了9组方案,研究叶片数、翼型、轮毂比和叶片与导叶间距离对轴流泵的扬程、效率、轴功率和压力脉动的影响规律,并通过综合频率分析法确定了一组最佳试验方案。结果表明:该最佳试验方案在设计流量下,水流在叶轮及导叶段中的流态较好,水流流线顺畅,分布相对均匀;轴流泵模型在流量和扬程满足改型要求的同时,效率提高了5.7%;轴功率下降了1.21%;压力脉动系数降低了11%,验证了综合频率分析法在多目标正交优化中的可行性。

The object is to improve the hydraulic performance of the axial-flow pump and find out the main geometric parameters that affect the performance of axial-flow pump. Based on the L9 （3^4） orthogonal experiment, number of blades, airfoil seating angle, hub ratio, the distance between the blade and guide vane were selected as test factors, and each experimental factor corresponded to three levels. Using orthogonal test method, the head, efficiency, shaft power and pressure pulsation were taken as the evaluation indexes. According to the results of intuitive analysis and range analysis, the best experimental scheme was determined by comprehensive frequency analysis. The results showed that hub ratio had the greatest influence on the four test evaluation indexes and the distance between blade and guide vane had the least effect. Under the optimum test plan, the flow regime was better, the whirlpool on the back of guide vane almost disappeared and the streamline on the blade surface distributed evenly. After optimization, the high pressure area of the blade surface disappeared basicaliy, and the pressure distribution was more uniform, and the optimization effect was better. Compared with the original model, the optimized model of axial-flow pump in the flow and head satisfied requirement for module at the same time, under the new design flow, efficiency was increased from 74.33% to 78.59%, which was increased by 5.7% ; shaft power was decreased from 20.54 kW to 20.29 kW, which was fallen by 1.21% ; pressure pulsation coefficient absolute value was decreased from 0. 344 to 0. 310, which was reduced by 11%. Four evaluation indexes were achieved and the optimized model of axial-flow pump had a wide range of efficient area and the feasibility of comprehensive frequency analysis method in multi- objective orthogonal optimization was verified.