Experimental and Numerical Investigation of Varying Stator Design Parameters for a Radial Turbine

The experimental and numerical investigations of five different vaned stators for a radial turbine are reported. Three different stator vane numbers and three different vane shapes were tested and modelled. The experimental tests were conducted at matched mass flow rates and pressure ratios, using the same 86 mm diameter turbine rotor, allowing direct comparison of the losses arising from each stator configuration. Stator vane number was found to have a small impact on measured stage efficiency (less than 1%), while vane shape was found to have a more significant effect (up to 4%). A commercial CFD code was used to construct a combination of full stage and single passage numerical models of the test turbine. Flow separation as a result of excessive incidence angle at stator inlet was shown to be a significant factor for some of the stators. Predicted pressure loss coefficients for the vaned stators were in the range 7–11%.