An aerodynamic design criterion was discussed for the 1+3/2 counter-rotating turbine by analyzing the velocity triangles. There are 8 key aerodynamic parameters in the criterion

based on the consideration of aerodynamic efficiency and some strength requirements. Then

an aerodynamic design for the 1+3/2 counter-rotating turbine was made according to the criterion

and a three-dimensional simulation was conducted for it. Finally

the conclusions were obtained. The criterion containing 8 key aerodynamic parameters is verified rationally and the efficiency of the turbine reaches 91%. The aerodynamic characteristics of 1+3/2 counter-rotating turbine are mainly decided by the load coefficient

and due to an optimal power distribution coefficient of the low pressure turbine

the efficiency of the low pressure turbine can be best.