气固两相透平叶片冲蚀特性的气动试验研究

Aerodynamic experimental investigation in blade erosion of gas-solid two-phase turbine

在自行研制风洞中先后对应用较广的MCrAlY叶片涂层和2Cr12Mo-5叶片合金、钢丸表面强化试件在不同气流速度、颗粒冲角、颗粒性状、颗粒粒度的条件下进行了气动冲蚀试验。试验结果表明,无论是涂层还是合金,冲蚀率均随冲蚀颗粒的累积质量呈线性变化;由对比可知,其它条件相同的情况下,涂层在广泛的冲角范围内较合金的冲蚀率更小,表面的"烧结"特征,能减小叶片的冲蚀率;表面呈多棱的石英砂颗粒对试件的冲蚀程度强于带突圆球状的催化剂颗粒;在该试验范围内,相同材质的颗粒,粒度愈大,对试件的冲蚀率愈大;钢丸表面强化工艺兼有防冲蚀的能力。试验结果将为优化叶片选材、简化叶片维修技术、降低叶片维修成本提供有益的参考。

This paper presents an aerodynamic investigation in erosion behavior of blade materials such as MCrAlY coating and 2Cr12Mo5 alloy, which are widely used in modern gassolid twophase turbine. A specimen treated by steelbead injection (SBI) is also tested. The experiments are carried out in a special windtunnel under different parameters such as different incidence angles, particle types, particle size and various particle speed so as to have a comprehensive understanding the abilities of these materials in erosion protection. Experiments have shown that (1) total erosion rate is increased with the particles number impinging the blade no matter what is coating or alloy or specimen after SBI, and (2) MCrAlY coating is less affected by erosion than 2Cr12Mo5 alloy in the wide range of incidence angles, and (3) silica particles with sharper shape cause severer erosion than that caused by catalyst with nearly sphere shape, and (4) for the same particle medium, larger particles lead to severer erosion to blade than smaller particles, and (5) the technology of SBI was firstly found to have the ability in erosion protection with cheap, convenient advantages although the duration of erosion protection is somehow less than MCrAlY coating. Results of the experiments offer significant data for optimizing blade material and economizing the blade maintenance in gassolid two phase turbines. 