Experiments on the Conical Diffuser Performance with Asymmetric Uniform Shear Inlet Flow : The Case of Diffuser with Free Discharge

抄録

One of the important factors affecting the diffuser performance is the shape of the inlet velocity profile. In this report, the results of measurements on a conical diffuser having various asymmetric uniform shear inlet flows are presented. Velocity distributions and pressure distributions were measured for four cone angles of diffuser and four degrees of shear of inlet flow for each diffuser. The main results obtained are as follows. Diffuser performance is decreased with an increased shear of inlet flow, and the reduction rate is maximum for a diffuser which has nearly an optimum shape for a uniform inlet flow without shear. With an increase of the inlet shear, a fixed large back-flow forms on the wall of the lower velocity side in the diffuser. This results in a decrease in the pressure recovery in the diffuser and also causes an increase in the outlet energy loss. A diagram indicating an equivalent cone angle of diffuser corresponding to that of one which has an inlet uniform flow is produced for the inlet shear.