Research On Hydraulic Optimization And Numerical Simulation Of Ultra-high Speed Centrifugal Pump

In this paper,the centrifugal pump in the ultra-high speed energy recovery machine is taken as the research object,and the method of combining theoretical analysis and numerical simulation is adopted.First,the hydraulic model of the ultra-high-speed centrifugal pump is optimized to obtain the optimized model,and then the original model and the optimized model Numerical simulation calculation under partial working conditions and cavitation conditions,and analysis and comparison of the external characteristic data and internal flow field distribution of the centrifugal pump.In addition,when the hydraulic model of centrifugal pump is optimized,the new optimization design method based on influence factor is adopted,which provides some new ideas for the study of hydraulic model optimization of centrifugal pump.The main content of this article is divided into the following parts:(1)The basic principle of fluid numerical simulation calculation is explained,and the hydraulic model of the centrifugal pump is established in UG.The SST turbulence model is adopted and the ANSYS CFX finite element simulation platform is used to carry out the numerical simulation calculation of the original model pump.Performance characteristic curve,efficiency loss distribution,and internal flow field analysis of inlet pipe area,runner area and volute area respectively.(2)Based on the distribution of the original model pump efficiency loss and the analysis of the flow state of the internal flow field,this paper selects the number of blades,the outer diameter of the blade,the inner diameter of the blade,the front profile of the blade,and the structure of the tongue as the optimization parameters.And according to the size of the influence factors of these structural parameters to determine the optimization sequence.By continuously modifying the structural parameters that the calculation model needs to optimize,establishing a new hydraulic model,and setting up new model calculations,an optimized model with better comprehensive hydraulic performance is finally obtained.The efficiency of the optimized model is increased by more than 8.8% compared with the original model,and the lift is increased.Over 55%,the expected goal of optimal design has been reached,and it is analyzed in combination with the external characteristic data and the distribution of the internal flow field.(3)On the basis of the original model and the optimized model,the steady simulation calculations under different flow conditions are carried out.According to the working performance curve of the centrifugal pump under different flow conditions,the distribution of the optimal operating point of the original model and the optimized model is obtained.Circumstances,and analyzed the reasons for the performance difference of the centrifugal pump before and after optimization in the large flow and small flow conditions.(4)In order to study the internal cavitation of the centrifugal pump under ultra-high speed conditions,this paper also carried out cavitation simulation calculations under different flow conditions on the original model and the optimized model,and obtained the cavitation degree of the centrifugal pump under different conditions.And the volume position distribution of the cavitation,and the performance comparison analysis before and after cavitation and optimization were carried out.Finally,some suggestions on how to improve the anti-cavitation ability of the pump are provided.