Influences of main design parameters on the aerodynamic performance of a micro-radial inflow turbine

The micro-radial inflow turbine (MRIT) is not only an important component of a micro-gas turbine but also the core part of a vehicle exhaust gas turbocharger and a small-scale organic Rankine circulatory system. Therefore, designing an MRIT with good performance is of great importance. The values of some main turbine design parameters can significantly influence its aerodynamic performance and structural size. In accordance with the structural characteristics of an MRIT, the relationships between the aerodynamic performance of a turbine and the absolute flow angle at the rotor inlet, the relative flow angle at the rotor outlet, the nozzle and rotor blade velocity coefficients, the ratio of the wheel diameter, velocity ratios, and the degree of reaction were examined. This was done through theoretical analysis combined with experience in the design of a conventional radial inflow turbine. On this basis, the influencing laws and degrees of the seven main design parameters on the aerodynamic performance of an MRIT during aerodynamic design were analyzed. The selection principles of these main design parameters were also summarized. The reasonableness of the above-mentioned selection principles was verified through an aerodynamic design case study of an MRIT combined with a 3D numerical simulation. It was found that the 3D numerical simulation results agreed well with the 1D aerodynamic design. The summarized selection principles of the main design parameters can provide a reference for the successful aerodynamic design of an MRIT.