Aerodynamic optimization of rotor blade of radial turbine under volute-impeller coupling condition

The coupling effect between the volute and the impeller influences the energy conversion of the working substance in the radial turbine and has a significant impact on the flow in the cascade and the overall performance of the turbine. Based on this， this paper conducts an optimization study on the rotor blade under the coupling condition of the volute with the blade expanded for the existing radial turbine geometry. The genetic algorithm and neural network algorithm are used to optimize the blade profile to obtain the rotor blade geometry with low loss and high efficiency in the installation state. The results show that although the efficiency of the impeller geometry optimized alone is 2.4% higher than that of the prototype impeller， the expansion ratio and output power decrease by 4.6% and 2.5% respectively after matching with the volute， and the overall performance of the turbine declines. Under the coupling installation condition of the volute and impeller， the efficiency of the impeller optimized is 1.01% higher than that of the prototype impeller， and the flow expansion ratio and output power increase by 2.28% and 2.29% respectively. The overall performance of the turbine is better than that of the impeller optimized alone， achieving the optimization effect of the impeller in the installation state.