The Optimization Of Full Passage Of Multi-Stage Centrifugal Pump Based On CFD Analysis

This paper mainly researches the influence of structure parameters of impellers,the volute and transitional flow passage on the head,power and efficiency of multistage centrifugal pump,and designs key parameters rationally to make the external characteristic curves of centrifugal pump satisfy National standards and design requirements.This paper first studies the hydraulic efficiency and head optimization of single-stage centrifugal pump.Based on the hydraulic loss model,a multi-objective optimization calculation method based on three surrogate models is proposed.The hydraulic loss model is used to analyze the sensitivity of design variables of single-stage centrifugal pump's impeller and volute to determine the key design variables.Based on the CFD analysis of key design variables,three kinds of surrogate models.According to efficiency and head optimization calculation method including the hydraulic loss method and the surrogate model method,combined with NSGA-? genetic algorithm,we find the optimal solution of the key design variables.The accuracy and the validity of two kinds of calculation methods are compared and analyzed.And the single-stage impeller with better performance is selected.Based on the optimized single-stage impeller,the matching between the impeller and the volute is optimized and the hump of the single-stage centrifugal pump is eliminated.Considering the working performance of the centrifugal pump under the conditions of high flow rate and low flow rate,we select excellent volute area ratio and volute base circle diameter.The structure of the suction chamber and the first impeller are determined by researching the cavitation of the first impeller.In order to reduce the hydraulic loss of the transitional flow passage between each stage of the 10-stage centrifugal pump,the reasonable diffuser tube and the transition part are designed,and the secondary impellers and the opposite secondary impellers are optimized,so as to make the head meet the design capacity requirement.According to the CFD numerical simulation analysis,the head and efficiency of the 10-stage pump based on the impeller 1 and the impeller 2 are 827.42 meters,75.33%,826.71 meters and 75.01%respectively,meeting the energy saving certification requirements of the national standards.Under the condition of low flow,the range of the whole pump's high efficiency zone based on the impeller 1 is larger than that of the whole pump's high efficiency zone based on the impeller 2.Under high flow conditions,the range of the whole pump's high efficiency zone based on the impeller 1 is smaller than that of the whole pump based on the impeller 2.