高参数汽轮机喷嘴材料抗固体颗粒冲蚀机制研究

Study on the Solid Particles Erosion Mechanism of Nozzle Materials in a Supercritical Steam Turbine

在设计、搭建的高温高速加速冲蚀试验台上对高参数汽轮机常用的6种喷嘴材料进行了高温抗固体颗粒冲蚀试验研究，并对试验后的材料表面进行了微观分析。研究结果表明：6种喷嘴母材均表现出典型的塑性材料冲蚀特性，最大冲蚀率对应的角度在（24±4）°范围内，速度指数在2．7～3范围，均高于Finnie冲蚀模型中的对应数值。在氧化皮颗粒小角度冲蚀下，喷嘴的冲蚀破坏主要足由颗粒的微切削所致。而在大角度冲蚀下，喷嘴材料表面主要受到粒子的正应力作用而产生严重的凿削和塑性变形。通过对试验结果进行系统分析，文中在Finnie微切削冲蚀模型的基础上建立了适用于工程实际的高参数汽轮机喷嘴材料抗吲体颗粒冲蚀预测模型。该研究结果深化了高参数汽轮机喷嘴高温颗粒冲蚀机制，为综合防治叶栅冲蚀破坏和预测喷嘴高效做功寿命提供了参考。

Based on the high-temperature high-speed accelerated erosion test facility, systematic solid particle erosion tests under high temperature were performed to six kinds of nozzle materials of high-parameter steam turbine, and a microscopic analysis was conducted to the eroded surface of specimens. Results show that： six kinds of the nozzle substrate exhibit typical erosion characteristics of plastic material. The maximum erosion rate angle is in the range of （24± 4）° and the velocity exponent 2.7-3, which are all higher than that of Finnie＇s model. Under the small angle impingement of oxide particles, the erosion damage of nozzle was mainly caused by the micro-cutting of particles. While under the large angle impingement, serious chopping and plastic deformation will generate on the surface of the nozzle by the impact positive stress from particles. Through systematic analysis of the test results, an erosion rate model for predicting the solid particle erosion of high-parameters steam turbine nozzles was established based on the existing micro-cutting erosion model from Finnie. The results of the study will deepen the high temperature erosion mechanism of steam turbine nozzles, and provide a basis for comprehensive prevention of solid particle erosion and predicting the high efficiency service life of nozzles.