Numerical Simulation And Optimization Design Of Submerged Axial Flow Pump Blade

As a low head,high flow rate pump,submersible axial flow pump is widely used in agricultural irrigation,ship propulsion and urban drainage.Among its many components,the impeller and guide vane are crucial.It is of great significance to improve the efficiency of the pump by adjusting and correcting the structural parameters of the impeller vane and guide vane in a relatively short period to achieve rapid optimization of the axial flow pump vane structure.This paper proposes the orthogonal test method based on Blade Gen software for the problem of low efficiency of submersible axial flow pump,takes a model of submersible axial flow pump as the research object,explores the influence of each parameter on the hydraulic performance of the axial flow pump,and completes the optimization of the impeller blade and guide vane parameters,and finally gets the efficiency of the submersible axial flow pump is 83.59%,which is more than 10%higher than before optimization.The main contents of the research in this paper are:（1）Through the wooden mold drawing of the impeller blade and the mapping data of the guide vane,a three-dimensional model is established by using UG combined with CAD method,and the model of the calculation domain is constructed.The appropriate mesh number,turbulence model and boundary conditions are selected and CFX is applied to numerical simulation of this submersible axial flow pump.By simulating this axial flow pump under different working conditions,the inlet and outlet angles of the impeller blades have the most influence on the flow state from the external characteristic parameters,BVF diagnosis and internal flow field analysis,and the optimization of the inlet and outlet angles parameters can improve the overall efficiency.Through the numerical simulation of this axial flow pump under different installation angles,it is found that the impeller domain hydraulic losses and guide vane domain hydraulic losses change differently when the blade installation angle changes,which indicates that the change of impeller blade parameters will affect the hydraulic efficiency of the guide vane domain,the matching problem of the blade and guide vane needs to be considered,and the factor of guide vane should be added in the orthogonal optimization process.（2）The three-dimensional model of the blade and guide vane is fully parameterizedbased on Blade Gen software,and each airfoil parameter is extracted for optimal design.Optimization before the first numerical simulation to compare the number of blades Z=4and the original number of blades Z=3 hydraulic performance,the difference is not large,so the optimization are selected 3 blades.The inlet angle and outlet angle at 50%leaf height of the impeller blade,the inlet angle,outlet angle and blade thickness at 50%leaf height of the guide vane were selected,a total of 5 factors.A 5-factor,4-level orthogonal test L₁₆（4⁵）was designed to orthogonally optimize the parameters of the blades and guide vanes.Through the extreme difference analysis,the factors that affect the hydraulic efficiency most are the blade inlet angle and the guide vane thickness.The optimal results of the orthogonal test are fine-tuned according to the flow field and analysis results,and the vane structure,parameters and internal and external characteristics are compared before and after the optimization.