离心泵多目标优化设计及数值模拟研究

Multi-objective Optimization Design and Numerical Simulation of Centrifugal Pumps

为进一步提高离心泵的优化设计水平,选择多目标优化与数值模拟相结合的方法,对一台低比转速离心泵进行优化分析,首先,以离心泵能量损失、抗气蚀性能及运行过程的稳定性为优化目标,离心泵叶轮的7个主要几何参数为设计变量,分别建立离心泵参数优化的数学模型,采用权矩阵分析的方法,给3个分目标函数分配相应的权值,并通过评价函数将它们统一为一个目标函数,利用遗传算法对目标函数进行多目标优化求解,得出叶轮7个设计参数的最优组合,将优化后的叶轮参数反代入优化模型中,结果显示离心泵的能量损失降低了4.3%,汽蚀余量降低了0.31 m;为进一步验证优化后泵运行的状态,根据优化后的叶轮参数建立离心泵水体三维模型,并利用CFX软件对水体模型做数值模拟分析,对比分析了优化前后流场中的压力脉动情况,结果显示优化后泵的蜗壳流道内压力脉动幅值降低了,优化后泵的运行稳定性有一定的提高。

In order to further improve the optimization design level of centrifugal pumps, a low specific speed centrifugal pump is optimized and analyzed by the method of multi-objective optimization and numerical simulation. First, the energy loss of centrifugal pump is used. The anti- cavitation performance and the stability of the operation process are the optimization objectives, and the seven main geometric parameters of the centrifugal pump impeller are the design variables. The mathematical model of the centrifugal pump parameter optimization is established, and the weight matrix analysis method is adopted. The corresponding weights are assigned to the three sub-objective functions, and they are unified into one objective function by the evaluation function. The multi-objective optimization of the objective function is carried out by using genetic algorithm, and seven impellers are obtained. The optimal combination of the design parameters and the optimized impeller parameters are put back into the optimization model. The results show that the energy loss and cavitation allowance of the centrifugal pump are reduced by 4.3% and 0.31 m. According to the optimized impeller parameters, the three-dimensional model of centrifugal pump water body is established, and the numerical simulation of the water body model is carried out by using CFX software. The pressure pulsation in the flow field before and after optimization is compared and analyzed. The results show that the amplitude of pressure pulsation in the volute flow channel of the optimized pump is reduced, and the operation stability of the pump is improved to a certain extent.