Application of CST Method on Modifying Leading Edge of Axial-Flow Turbine Blade

In order to explore the effects of leading edge modified with the method of CST (Class Function/Shape Function Transformation Technique) on the aerodynamic performance of the blade profile, firstly, the implementation details of CST method in leading edge reconstruction are improved. Secondly, the effects of Reynolds number on profile losses and boundary layer characteristics are studied with numerical simulation. Finally, the practicability of the CST leading edge modification method is verified in the low-pressure turbine of a new high-speed aircraft. The results show that the CST method can eliminate the pressure spike and separation bubble near the suction leading edge of HD profile, which also delays the transition phenomenon induced by the suction leading edge separation bubble under high Reynolds number condition and expands the range of low-loss state Reynolds number. In addition, the profile loss is reduced by 32%. The reduction of suction profile loss under low Reynolds number condition is mainly from the shear layer near the leading edge, while the reduction of suction profile loss under high Reynolds number is mainly from the shear layer near the leading edge and the laminar boundary layer before diffuser section. The application of CST leading edge modification in high-speed aerospace vehicle low-pressure turbine rotor is verified to be effective on improving the aerodynamics efficiency, that making a contribution to increasing the efficiency by 0.1% around the design point and about 0.3%~0.5% at lower expansion state with large negative incidence. The position where the loss is reduced is mainly concentrated in the boundary layer of pressure side and the secondary flow region near the root. © 2019, Editorial Department of Journal of Propulsion Technology. All right reserved.