Numerical Simulation And Experimental Study On Axial Force Of Centrifugal Pump

The magnitude of the axial force of the centrifugal pump directly affects the safety and stability of its operation and life,axial force is currently one of the main hotspots of the relevant scholarly research.Axial force refers to the impeller in the work of the force along the axial direction,mainly due to the fluid on the impeller recoil and the impeller before and after the cover plate inside and outside the pressure value is not equal and caused by the axial pressure difference.The axial force will lead to the rotor towards the impeller inlet axial movement and cause the mouth ring wear,increase the thrust bearing overload and cause bearing burn,and even lead to the pump can not run normally and other accidents.Therefore,when developing and designing centrifugal pumps,it is of great engineering importance to accurately predict the impeller axial force.In this thesis,the force characteristics of the axial force of centrifugal pumps under multiple flow conditions under complex flow fields were studied,and develop a piezoelectric axial force measurement device.The full flow channel fluid domain of the centrifugal pump were modelled in 3D using UG software and associated with ANSYS Workbench,the fluid domain model was segmented and meshed using ICEM,and the internal flow field and axial force of the centrifugal pump were studied by numerical simulation using Fluent.(1)Based on one guide vane cycle,five different guide vane circumferential position simulation calculation models were established to explore the influence of guide vane circumferential position change on the internal flow field and axial force of centrifugal pump.It is found that the axial force decreases first and then increases and then decreases with the change of the circumferential position angle α the guide vane.When the circumferential position of the guide vane is α=6°,the circumferential asymmetry of pressure distribution in the pressurized water chamber is relatively weak,the streamline line at the outlet of the guide vane is more stable,and the axial force is relatively small.(2)By changing the gap of the front mouth ring and the shape of the front chamber,a simulation calculation model is established to explore the influence of the change of the two parameters on the flow field and axial force of the centrifugal pump.It is found that the axial force on the impeller decreases with the decrease of the front mouth ring gap,and the decrease in the volume of the front chamber also reduces the axial force on the impeller.(3)Based on the axial force measuring device of the developed piezoelectric sensor,the axial force of the impeller was experimentally measured,and it was found that the axial force of the impeller gradually decreased with the increase of flow,and compared it with the simulation value,the maximum relative error was 6.5%,and the relative error under the design condition was 1.4%.It shows that the numerical calculation method of axial force can accurately predict the axial force of the centrifugal pump.