Investigating the effect of blade sweep and lean in one stage of an industrial gas turbine׳s transonic compressor

Abstract

In this paper, the simultaneous effects of the sweep and lean of the blades in one stage of a transonic compressor on its performance have been investigated. Then, with the help of numerical solution, fluid flows over these two modified geometries generated from the original sample were analyzed. Considering the applied constraints, the two generated rotor geometries have different geometrical characteristics; so that in rotor No. 1, the blade has a backward sweep and it is less affected by lean, while in the modified rotor No. 2, the blade has a forward sweep and it is more affected by lean. In the first sample, it is observed that the stage efficiency increases by 0.5% for operating design, while the stall margin reduces, and the chocking mass flow rate diminishes by 1.5%. Also regarding the second modified blade, the results indicate that the stall margin increases, the choking flow rate at the nominal rotational speed of the stage increases by 0.18% and the stage efficiency increases by 1%. The comparison of numerical results also shows that, in the first modified rotor, the pressure ratio of the stage diminishes by 0.01%; while in the second sample, the pressure ratio of the stage increases by the same amount. These results were then compared with the experimental results, showing a good agreement.

Keywords

• Blade sweep and lean
• Stacking line
• Modified blades
• Choke mass flow rate
• Efficiency