| The centrifugal fan is one of the important parts in a knapsack sprayer. In this study, the inner flow field in the centrifugal fan of the knapsack sprayer is numerically simulated and analyzed with the help of FLUENT software. The numerical simulations are based on two-dimensional N-S equations and the Realizable k-εturbulence model. The finite volume method and SIMPLEC algorithm are adopted.In order to improve the quality of meshes and save the computing time or memory, the flow field is divided into different blocks and the triangular meshes are suitably set up for every block. The standard wall functions are adopted near the wall. The centrifugal fan contains rotary impellers and other static parts. The initial boundary conditions are defined according to the experiments. Velocity boundary condition is defined at the inlet. And pressure boundary condition is defined at the outlet.The results of simulation show many essential phenomena of the flow in the centrifugal fan. These results represent some important flow characteristics in the centrifugal fan. It means the reliability of FLUENT software in simulating the flow field of centrifugal fan.Experiments prove that the speed curve in numerical simulations and experimental measurements are coinciding, and the numerical error is less than 5 percent. The numerical simulation method used in this study is feasible.Inlet angle of impeller, the shape of volute tongue and impeller size are important parameters of the internal flow field. In this study, the flow fields of the fan with these different parameters are separately numerically simulated. The influence rules of these parameters on the inner flow field can be found. The simulation and analysis lay a good foundation for optimal design of a centrifugal fan. The results of the simulation indicate that with the right angle of imports, the fan flow field inside the fan seems better. The shape of volute tongue and impeller size also has a huge impact in the inner flow field.
|
PDF Full Text Request