Aerodynamic design of three-stage vaneless counter-rotating turbine

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.