Numerical Simulation Of The Gas-solid Two-phase Flow Field In The Centrifugal Fan

The centrifugal fan, which has been widely used in various industries, is one kind of fluid machinery. In this article, a method of simulation for the gas-solid two-phase flow field in backward-blade centrifugal fan with high efficiency, which is style 4-72, has be developed.In the simulation of gas flow, the finite volume method (FVM) is selected. The three-dimensional time averaged N-S equation, the RNG k -ε turbulent model and the mixed mesh are used. Then the Lagrange particle track model and the uniphase coupling method are used to simulate the gas-solid two phase flow field in the centrifugal fan. In order to make sure that the flow is fully developed, two additional pipes are added to the inlet and the outlet of the centrifugal fan. The fluid zone is divided into four regions when it is meshed. The unstructured grid with small dimension is selected in the regions where the flow is complex, on the other hand the structured grid with large dimension is selected in the inlet and the two additional pipes in which the flow is not complex. The moving reference frame is used in the impeller region and the boundary conditions are velocity inlet and pressure outlet. When the computation is converged, the discrete phase injection is set in the inlet of the simulation model and the solid particle is tracked by the uniphase coupling model. Some flow phenomena are captured in simulation of gas flow, for example the separation of the boundary layer, the secondary flow and the gap flow. The tracks of the particles with different diameters in the centrifugal fan are obtained in the simulation of solid-gas flow too.The results of simulation are coincident with the experiment, it shows that the method of simulation developed in this article is reliable and can be used to guide the optimum design of the centrifugal fan.