Study On The Influence Of Guide Vane Parameters On Hydraulic Performance Of Bidirectional Axial Flow Pump

In recent years,as China’s ecological environmental protection management of large rivers and major lakes wetlands,the increasing demand for new mechanisms for wetland ecological protection,the conventional one-way pumps used in general engineering construction can no longer adapt to the country’s need for two-way regulation in the management process of wetland ecological protection,to ensure the smooth implementation of wetland ecological management,the demand for two-way axial flow pumps is also increasing,so Research and development of two-way axial flow pump has become a major issue.The guide vane is an important overflow component for energy recovery in the axial flow pump,and the guide vane inlet and outlet placement angle and guide vane chord length are important parameters in the design of the guide vane,which have an important impact on the efficiency of the axial flow pump.In order to study the influence of the above three guide vane parameters on the operating performance of a two-way axial flow pump,this paper takes an axial flow pump with a specific speed of 903 as the object of study and simulates it numerically using a standard k-?turbulence model in ANSYS-CFX software,and uses the numerical calculation results to analyze the internal flow characteristics,hydraulic performance,pressure pulsation,axial force and radial force of the two-way operation of the axial flow pump and determine the best guide vane parameters for the development of forward and reverse operation.The results of the numerical calculation are used to analyze the internal flow characteristics,hydraulic performance,pressure pulsation,axial force and radial force of the axial flow pump in both directions,to determine the optimal guide vane parameters,and to provide a reference basis for developing a bi-directional axial flow pump with efficient performance in both forward and reverse operation.The main results of the study are as follows:（1）Increase the guide lobe outlet angle will make the axial flow pump efficiency decreases in positive rotation,guide lobe flow disorder,vortex and off-flow phenomenon intensified,thus causing the back of the guide lobe low pressure area increased;pressure loss in the discharge pipe intensified,resulting in the overall hydraulic loss in the axial flow pump increased;but will make the reverse rotation of the guide lobe body flow field stability,off-flow phenomenon reduced,thus reducing the hydraulic loss,efficiency increased.Excessive increase or decrease the guide lobe outlet angle will increase the amplitude of pressure pulsation and fluctuations,the appropriate selection of the guide lobe outlet angle,the pump device pressure pulsation in the situation has improved.The radial force on the guide lobe increases with the increase of the guide lobe outlet angle,and the axial force increases with the increase of positive rotation,but decreases with the reverse rotation.Therefore,the overall selection ofβ₂=80°,the performance in both forward and reverse directions are optimal.（2）Increasing the inlet angle of the guide vane can improve the ability of the guide vane to recover energy when the axial flow pump is turning,improve the internal flow state of the guide vane,thus reducing the pressure loss in the guide vane and in the discharge pipe,which makes the efficiency of the two-way axial flow pump increase;when reversing,the efficiency increases with the inlet angle and then decreases,the hydraulic loss in the discharge pipe still decreases with the increase of the inlet angle,but the hydraulic loss at the guide vane continues to increase.In reverse operation,increasing the inlet angle of the guide vane can increase the amplitude of pressure pulsation;in forward operation,the pressure pulsation at the outlet of the guide vane increases with the increase of the inlet angle,but the amplitude of pressure pulsation at the outlet of the impeller decreases with the increase of the inlet angle.The radial force at the guide vane decreases as the inlet angle decreases,but it increases the axial force in forward operation.In order to have good performance in both forward and reverse directions,β₁=49°is selected.（3）Under the design condition,the efficiency and head of the pump will increase with the increase of chord length,and the maximum efficiency and head value will be obtained at l=104mm,the forward hydraulic loss will decrease with the increase of chord length,and the minimum hydraulic loss value will be obtained at l=104mm in forward operation,the reverse change law is opposite,and the change is small;the pressure pulsation pressure and radial force values obtained by non-constant calculation will increase with the increase of chord length of guide vane,and the maximum value will be obtained at l=104mm,and the axial force will decrease with the increase of chord length and the minimum value will be obtained at l=104mm.