A Comparison of Calculated Flows in Radial Turbines With Experiment

The flow in the rotors of three radial turbines, of differing peak efficiency, is analyzed using a streamline curvature method. The turbine of greatest efficiency is analyzed at both on- and off-design conditions; the other two turbines at the design point only. Comparison is made between the predictions of the calculation and the experimental determination of two features of the flow — the shroud static pressure distribution and the outlet velocity profile. Fair agreement with the shroud pressure is obtained at on-design conditions, but correlation with the exit velocity distribution is poor. Some improvement in the calculation of the exit profile is achieved when the analysis is modifed so as to allow for the experimentally observed angle of deviation at the blade trailing edge. Consideration is given to the ability of the analytical method to discriminate between turbines which prove experimentally to have high or low peak efficiency.