| Centrifugal pumps are divided into closed impeller centrifugal pumps,semi-open impeller centrifugal pumps and open impeller centrifugal pumps.In order to avoid friction during the normal operation of the pump,there is a certain axial clearance between the top of the impeller blade and the pump casing,tip clearance is an important parameter of the semi-open impeller,it will not only affect the external characteristics,but also endanger the stable operation of the pump.This study takes a semi-open impeller centrifugal pump as the research object,using the SST k-ω turbulence model,and studies its two aspects based on the orthogonal test.One is the axial force balance of the semi-open impeller centrifugal pump,the other is the semiopen impeller centrifugal pump.The problem of hydraulic characteristics of impeller centrifugal pump.The results of the study are as follows:1.Research on the influence of different combinations of tip clearance and balance hole size on the axial force of semi-open impeller centrifugal pump based on orthogonal testIn this study,blade tip clearance and balance hole diameter were selected as experimental factors,each factor took 5 levels,and 25 groups of experimental programs were designed,and the optimized program was obtained by analyzing the numerical calculation results of the 25 groups of experimental programs.Under the premise of ensuring that the efficiency of the centrifugal pump under the constraint conditions is not less than 39.5%,the results show that by reducing the size of the tip clearance and opening the balance hole,the pressure in the rear cavity is significantly increased,and the axial force of the centrifugal pump is greatly reduced,and the largest drop reached 478.65N,accounting for 74.25%of the total axial force of the original model.At the same time,the impact on the pump performance is not great,the efficiency is only reduced by 3.57%,and the head is only reduced by 0.3%.2.Research on the influence of different combinations of width and number of semi-open impeller back blades on axial force of centrifugal pump based on orthogonal testIn this study,the width of the dorsal leaves and the number of leaves were used as the experimental factors,and each factor was taken as 5 levels.25 groups of experimental programs were designed,and the optimization program was obtained through the analysis of the numerical simulation results of the 25 groups of experimental programs.The results show that under the premise of ensuring that the efficiency of the centrifugal pump under the constraint conditions is not less than 39.5%,by increasing the width and number of the back vanes,the axial force of the centrifugal pump is greatly reduced,and the maximum reduction is 552.58N,accounting for 85.71%of the original plan’s axial force.At the same time,the impact on the pump performance is not great,by comparing with the calculated results of the original scheme,The optimized scheme has a 6.2%increase in head,and its efficiency is only reduced by 3.81%.3.Research on the influence of different combinations of semi-open impeller tip clearance and blade wrap angle on the performance of centrifugal pump based on orthogonal testIn this study,blade tip clearance and blade wrap angle were selected as experimental factors,each factor was set to 5 levels,25 groups of experimental schemes were designed,and the optimized scheme was obtained by analyzing the numerical simulation results of the 25 groups of experimental schemes.The results show that the pump head and efficiency can be effectively improved by reducing the size of the tip clearance and increasing the wrap angle of the impeller blades of the semi-open centrifugal pump.And the maximum increase in lift is 1.12m,accounting for 18.67%of the lift of the original model,and the maximum increase in efficiency is 8.16%. |
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