Research On Performance Optimization Study Of Guide Vane Centrifugal Pump Based On Improved Grey Wolf Algorithm

The guide vane centrifugal pumps are widely used in long-distance water transfer projects,and their operating efficiency is directly related to the efficient and energy-saving of the entire system.Moreover,the arrangement of guide vanes leads to more complex internal flow patterns and stronger pressure fluctuations,which is not conducive to the stable operation of the entire water regulation system.Therefore,effectively improving the operating efficiency and stability of guide vane centrifugal pumps is of great practical significance for long-distance water transfer.This article selects the guide vane centrifugal pump of a certain pumping station as the research object,combines CFD technology and an improved grey wolf optimization algorithm to optimize the impeller blades,and studies the relationship between the guide vane distribution circle diameter and the pressure pulsation of the centrifugal pump in-depth.The main research contents are as follows:(1)The principle,mathematical model,and existing problems of the basic grey wolf optimization algorithm are systematically introduced.To address these problems,the method of optimal Latin hypercube sampling,dynamic weight factor,a new type of nonlinear convergence factor,and the addition of local disturbance are used for improvement.At the same time,14 different standard test functions are used to test different optimizations.By comparing the mean,standard deviation,and convergence speed,it is found that the improved grey wolf optimization algorithm has better optimization accuracy and convergence speed compared to other algorithms.(2)On the Matlab platform,the centrifugal pump efficiency is taken as the optimization objective,and the geometric parameters(inlet and outlet angles and thickness)of the blades at Span=0.33 and Span=0.66 are taken as the optimization variables.By calling the Workbench platform to achieve parameterization of the impeller(controlled by Bezier curves),grid partitioning,and numerical simulation,joint optimization is completed.The comparison results show that under the design condition,the efficiency of the centrifugal pump is improved by 0.3%,and the head is increased by 0.3m,and the optimization effect is more significant under off-design conditions.At the same time,the internal flow field of the optimized centrifugal pump has also been improved.(3)The distribution circle of the guide vanes has a small influence on the average pressure inside the centrifugal pump but has a significant impact on the stability of the pressure curve.The pressure curve stability is most affected by monitoring points near the hub,special guide vanes in the bladeless area,and the tongue of the volute casing.Unlike the bladeless area and volute casing,the distribution circle has a significant impact on the main frequency inside the impeller,mainly manifested when the distribution circle diameter is too large or too small.Overall,increasing the diameter of the guide vane distribution circle can effectively reduce the amplitude of various main frequencies.(4)The influence of the guide vane distribution circle on the main frequency amplitude of the impeller at the same section is the same,gradually increasing from the front cover plate to the back cover plate.In the bladeless area,the influence of the guide vane distribution circle on each monitoring point is mainly reflected in the circumferential direction,and there is little change in the axial direction at each monitoring point.There is a threshold for the influence of special guide vanes on the waveform and amplitude of pressure pulsations in the bladeless area,and once exceeded,its influence will quickly decrease,similar to ordinary blades.Overall,the ratio of the guide vane distribution circle diameter to the impeller outlet diameter is better at 1.165-1.175.