Aerodynamic optimization of a high-expansion ratio organic radial-inflow turbine

Given that the radial-inflow turbine is a critical component of the Organic Rankine cycle system, its performance substantially influences system capacity. This paper established an optimization framework for the radial-inflow turbine is established with the combination of a computational fluid dynamics software, a non-uniform rational B-spline parameterization method, and an optimization strategy. The nozzle, meridional flow path, and blade profile of a 500 kW turbine were optimized. Results show that nozzle blade and impeller optimization leads to a 0.34 % and about 0.71 % increase in turbine efficiency, respectively. After optimization, the flow state in the turbine was good, and the flow separation almost disappeared.