Effect of oblique stator on the aerodynamic performance and erosion characteristics of governing stage blades in a supercritical steam turbine

Abstract

In this article, a new particle tracking model is established through high temperature erosion modeling test. Based on the model, steam-particle flows in the governing stage cascade of a supercritical steam turbine are systematically investigated and the influence of oblique stator on the aerodynamic performance and erosion characteristics of governing stage blades is carefully studied. Results show that with the increase of nozzle oblique angle, the maximum load position gradually moves toward nozzle trailing edge. Consequently, secondary flow loss of nozzle cascade gradually decreases. Compared with the prototype structure of governing stage, stage efficiency increases by 0.8%, 0.35%, and 0.44%, respectively, when nozzle oblique angle increases to 15°, 30°, and 45°. Meanwhile, erosion at the trailing edge of nozzle pressure side and leading edge of rotor suction side gradually decreases, while erosion of rotor pressure surface increases. The maximum erosion position of nozzle pressure surface and rotor suction surface keeps constant, but the maximum erosion position of rotor pressure surface gradually moves forward. Comprehensive analysis shows that when nozzle oblique angle reaches 30°, erosion of nozzle trailing edge reduces by 14%, and stage efficiency increases by 0.35%; erosion resistance and aerodynamic performance of governing stage can be both well considered.