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.
Highlights
Solid particle erosion (SPE) of steam turbine components, including nozzles, rotors, valves, remains an intractable challenge for supercritical coal-fired power generation technology around the world
Trajectory of particles smaller than 10 mm in the cascade is close to the direction of stream flow, and a large amount particles escape without impacting cascade surface
Compared with the prototype governing stage cascade structure (g = 0°), governing stage cascade with g = 30° nozzle oblique angle can reduce the erosion weight loss at the trailing edge of the nozzle by 14%, and the stage efficiency increases by 0.35%
Summary
Solid particle erosion (SPE) of steam turbine components, including nozzles, rotors, valves, remains an intractable challenge for supercritical coal-fired power generation technology around the world. With the continuous development of steam turbine design technology, a unique oblique stator structure, which is installed between the radial intake channel and axial turbine cascade in ultra-supercritical steam turbine high pressure cylinder and medium pressure cylinder, is proposed by some turbine manufacturers. Summarizing the above literatures, it is found that steam turbines configured with oblique stator structure in high pressure first-stage cascade and firstreheat stage cascade may be the most effective method to reduce blade erosion. 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 are carefully studied. The results of this study reveal the anti-erosion mechanism of oblique stator structure and provide a theoretical basis for preventing and reducing the erosion of high-parameter turbine blade. The change of particle velocity in each time step depends mainly on the acceleration characteristics of the particles dUp dt 1 mp
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