Study of Unsteady Flow Simulation of Backward Impeller with non-uniform Casing

摘要

The flow characteristics in the centrifugal fan with difference blade ontlet angles are basically discussed on steady and unsteady simulations for the rectangular casing fan.The blade outlet angles of the impellers are 35° and 25° respectively.The unsteady flow behavior in the passage of the impeller 35° is quite a difference in the steady flow behavior.The large flow separation occurs in the steady flow field and unsteady flow field of the impeller 35° that the flow distribution of the circumferential direction is varied much and the flow separation on the blade is occurred only at the back region of the fan.But the steady flow behavior in the impeller 25°is almost agreed with the unsteady flow behavior that the flow distribution of the circumferential direction is not varied so much and the flow separation on the blade is hardly occurred.When the circumferential variation of the flow in the impeller is large, the steady flow simulation is not coincident to the unsteady flow simulation.