Research On Flow And Wear Characteristics Of Solid-liquid Two-phase Flow In A Rotating Runner

In the solid-liquid two-phase transportation industry such as water conservancy engineering,ore mining and dredging,the centrifugal pump that provides power has the advantages of simple structure,high transportation effciency and easy installation,so it is widely used.However,the existence of solid phase particles causes the wear phenomenon of the continuous flow parts in the centrifugal pump caused by the continuous impact of the particles,especially in the impeller area,which directly leads to the reduction of the lift efficiency of the centrifugal pump and the service life,and even causes safety risks during production.Due to the changes in the speed of the centrifugal pump impeller and the solid-phase particle concentration in the solid-liquid two-phase flow,different wear characteristics will be formed on the surface of the impeller blade.Therefore,this paper use a combination of numerical simulation and experiments to study the flow characteristics of solid-liquid two-phase flow and blade surface wear distribution at different speeds and different particle concentrations in the impeller flow path,providing theoretical support for the design of anti-wear impellers.The main research contents are as follows:(1)Simplify the centrifugal pump impeller structure and complete the rotating disk design with three straight blades.A wear test bench was set up to perform a rotating disc wear test.The rotation speed of the disk was 400rpm,500rpm,600rpm,700rpm,800rpm and the particle mass concentration was 2%,4%,6%,8%,and 10%.The laser displacement sensor was used to measure the thickness of the wear blades,and it was found that the wear thickness loss in the lower area was higher than that in the upper wear area.With the increase of rotational speed and particle mass concentration,the average wear rate of the blade wear area at the working surface gradually increase.When the particle concentration was above 8%,the average wear rate tended to be stable.The super-depth of field microscope was used to analyze the micro-morphology of the exit area of severe blade wear.It was found that the blade wear severe area would produce wear ripples after the increase of particle concentration and rotational speed.And the ripple spacing would extend with the increase of rotational speed and particle concentration.The undulations of the gully height along the flow direction of the solid-liquid two-phase flow on the blades increase with the increase of particle concentration and disc rotational speed.(2)The work use Solidworks to model the disk fluid computing domain and use the meshing software ICEM to mesh the disk computing domain model.Further,it use the computational fluid dynamics software FLUENT select the CFD-DPM coupling method,and add the wear model to complete the solid-liquid Phase flow calculation.The analysis of the wear area of the calculation results shows that the severely worn areas are all in the outlet area of the blade working surface,and the wear area extends to the blade inlet area with the increase of the speed and mass concentration.It was found that the wear rate increases with the increase of rotational speed and particle concentration from the wear data which were extracted from the worn blade surface.The wear rate tended to be stable when the particle concentration was above 8%.The experimental data were compared with the simulated data to verify the reliability of the numerical simulation.