Research On The Influence Of The Setting Angle Of The Blade Outlet On The Performance Of Centrifugal Pump Based On Fluid-Structure Coupling

As a general-purpose machine that converts mechanical energy into fluid kinetic energy,centrifugal pumps are widely used in industry,agriculture,aerospace and other fields.Therefore,high-efficiency,stable and safe operation of centrifugal pumps is particularly important.The impeller of a centrifugal pump is a key flow component of a centrifugal pump.The blade outlet setting angle is an important geometric parameter of the impeller.Whether its choice is reasonable or not directly determines the performance of the centrifugal pump.The high-speed rotation of the centrifugal pump rotor interacts with the fluid inside the pump,causing abnormal vibration of the centrifugal pump,and severe structural damage will occur.Therefore,this paper has carried out a numerical simulation study on the centrifugal pump with different blade outlet angles under the action of two-way fluid-solid coupling.The main research contents and results are as follows:（1）Establish fluid domain and solid domain models of centrifugal pumps with blade outlet angles of 22°,24°,26°,28°and 30°through 3D modeling software,Through ANSYS software,the steady-state flow numerical simulation of centrifugal pump is carried out under 0.6Q_d,0.8Q_d,1.0Q_d,1.2Q_d and 1.4Q_d,The results show that the centrifugal pump achieves the best efficiency near the design flow rate,The increase of the blade outlet angle will make the high speed area in the volute under 1.0Q_d and the turbulent kinetic energy area of the impeller under0.6Q_d increase first and then decrease,but it has little effect on the static pressure distribution of the impeller and volute.（2）Taking the steady-state simulation results of the centrifugal pump as the initial conditions,the transient flow numerical simulation of the centrifugal pump without considering the fluid-solid coupling and considering the fluid-solid coupling was performed at 0.8Q_d,1.0Q_dand 1.2Q_d,respectively,and the impeller was analyzed.And the pressure pulsation of the volute channel and the radial force of the impeller.The results show that the pressure of the centrifugal pump impeller and the volute channel changes periodically under both the non-fluid-structure coupling calculation and the fluid-structure coupling calculation.The fluid-structure coupling calculation The pressure fluctuation of the flow channel of the centrifugal pump,the pressure fluctuation amplitude of the volute flow channel and the change interval of the radial force of the impeller are all larger than those under the non-fluid-structure coupling calculation.The change of the blade outlet angle has a greater influence on the pressure of the centrifugal pump impeller and volute passage under the fluid-solid coupling calculation than that under the non-fluid-structure coupling calculation;the pressure fluctuation and the pressure fluctuation of the impeller passage of the centrifugal pump withβ₂=22°under small flow The radial force fluctuation of the impeller is more uniform than other centrifugal pumps.（3）Analyze the solid domain part after the two-way fluid-solid coupling calculation by ANSYS Workbench software at 0.8Q_d,1.0Q_d and 1.2Q_d,and perform modal analysis on the centrifugal pump rotor under prestress.The results show:centrifugal pump The maximum deformation and maximum equivalent stress of the rotor show obvious periodic changes with the rotation of the impeller.The maximum stress of the centrifugal pump rotor is not enough to cause the structural yield of the rotor.The maximum deformation of the centrifugal pump rotor withβ₂=22°is the smallest,and the centrifugal pump rotor The influence of the maximum stress with the change of operating flow is small.The second and third natural frequencies of the centrifugal pump rotor under prestress are basically the same as the fourth and fifth natural frequencies.The swing directions of the vibration modes are perpendicular to each other.The sixth and previous vibration modes of the rotor are quite different.The largest deformation occurs at the shaft end.