Effect of blade leading edge on aerodynamic performance of turbine

Geometry of turbine blade leading edge was altered from circular to non-circular by using the Bezier curves methods, based on which numerical analysis and comparison were made to illustrate how turbine cascade leading edges affected the aerodynamic performance under different attack angles. Within the normal operating range of attack angle (-15°~+10°), the non-circular leading edge had a better performance as the gradual increase of the curvature radius of the non-circular leading edge reduced the normal pressure gradient of the leading edge, which further restrained the flow from excessively expanding and reduced the energy dissipation caused by the viscous stress, resulting in a decreased flow loss, and the bigger the curvature radius of the non-circular leading edge, the better the performance. Whereas under the large attack angle of the non-design condition, the gradual increase of the curvature radius would cause more severe cascade separation, which aggravated the loss, and it was exemplified by the case of a five-stage low pressure turbine. Numerical analysis has indicated that the non-circular leading edge can improve the flow features and increase the turbine efficiency. However, for the non-design condition estranging from the design point, the flow attack angle alters so substantially that it has negative effect on the turbine aerodynamic performance.