Numerical Simulation And Experimental Study On Radial Force Of Centrifugal Pump

During the operation of the centrifugal pump,whether it can run smoothly has always been an important factor for people to judge the performance of the centrifugal pump,and radial force is one of the main reasons that can affect the stability of centrifugal pump.Radial force refers to the force in the radius direction received by the impeller in the rotating work,it is mainly caused by the uneven distribution of the liquid pressure around the impeller and the inlet water flow.The radial force can make the shaft seal clearance of the centrifugal pump larger.Once the radial force is too large,it will lead to the leakage of centrifugal pump.Therefore,it is key for the design of water pumps to predict the radial force.At present,there are three main methods to study radial force,including empirical formula method,test method and the numerical simulation method.The empirical formula method has large errors,so it is difficult to accurately calculate the force value.The test method needs to design a force measuring device to carry out the fluid mechanics experiments.The numerical simulation technology used to analyze the internal flow field of rotating machinery has become more and more mature with the continuous improvement of computational fluid dynamics(CFD)and finite element analysis(FEA).This paper studies the characteristics of the radial force of a centrifugal pump in a complex flow field based on the numerical simulation,and develops a force measuring device for the radial force of a centrifugal pump.Solid Works software is used to model the impeller and volute of the centrifugal pump in 3D,which is associated with ANSYS Workbench.ICEM CFD software and Fluent software are combined to realize the meshing of the imported model and the numerical simulation of the internal flow field of the centrifugal pump.The flow-head characteristic curve and the radial force under various working conditions were obtained.The influence of wrap angle on radial force was analyzed.Combined with the internal structure of the centrifugal pump,a set of radial force measurement device based on piezoelectric sensors was developed.The static calibration of the force measurement device was completed on the test bench,and the static performance index of the three groups of sensors was obtained,the linearity was 0.16%,0.12%,0.18%,and the repeatability was 0.06%,0.06%,0.12%,respectively.Finally,the radial force was measured experimentally,it was found that as the flow rate increases,the radial force first becomes smaller and then becomes larger.When the flow rate is the design flow rate,the radial force is the minimum.The maximum relative error is 8.1%,and the relative error under rated conditions is 2.08% between the experimental results and the simulation result.It is proved that the numerical simulation method and the measuring device can accurately predict and verify the radial force of the centrifugal pump.