Flow analysis and design of radial inflow turbine guide vanes for microturbine

The general design principles on shape-design of radial inflow turbine guide vanes were discussed. Five kinds of guide vanes were designed with different thickness of trailing edges, and the flow fields in the guide vanes passage were investigated by 3-dimensional viscous numerical simulation. The results indicate that with the present general design principles for radial inflow turbine guide vanes, high flow efficiency of the high-subsonic guide vane can be obtained, and the radius of the radial inflow turbine can be reduced effectively. Relative thickness of the trailing edge has important impact on flow efficiency and characteristics. If relative thickness of trailing edge increases 1%, inlet flow angle of the impeller will reduce 0.03 degree and velocity coefficient of the guide vanes will reduce 0.1%. Therefore, in order to achieve high aerodynamic performance the thickness of trailing edge of guide vanes should be within the range of 0.6 to 1.0 millimeter and the relative thickness of trailing edge less than 15%, based on the present study with consideration on the available super alloy cast technology.