Abstract
The flow characteristics of the turbo fan with a rectangular casing are investigated with experiments and simulations. The length of the casing is varied. It is cleared that the performance of the fan is not influenced with length of the rectangular casing. The pressure on the casing varies with the section geometry, but the pressure out of the impeller varies mainly with the distortion of the net flow. When the net flow out of the impeller increases, the pressure decreases at the outlet of the fan. The discrete frequency noise from the fan is mainly generated by the interaction of the distorted net flow and the blades.
