基于流场仿真的某型涡轮叶片的表面微结构分析  

Analysis on Turbine Blade Surface Microstructure based on CFD

作　　者：刘士杰 李伟 王慧[1] 梁国柱[3] LIU Shijie;LI Wei;WANG Hui;LIANG Guozhu(Laboratory of Science and Technology on Cryogenic Liquid Propulsion of CASC,Beijing Aerospace Propulsion Institute,Beijing,100076;Beijing Aerospace Propulsion Institute,Beijing,100076;School of Astronautics,Beihang University,Beijing,102206)

机构地区：[1]北京航天动力研究所低温液体推进技术实验室,北京100076 [2]北京航天动力研究所,北京100076 [3]北京航空航天大学宇航学院,北京102206

出　　处：《导弹与航天运载技术（中英文）》2024年第2期32-41,共10页Missiles and Space Vehicles

基　　金：国家高新技术发展计划。

摘　　要：利用流场仿真和扫描电子显微镜观测的方法,对某型涡轮叶片工作前后的表面微形貌进行了分析,研究了高温高压环境对叶片表面形貌变化的影响。首先为了提高计算效率,根据叶片形式,建立了涡轮叶片流场的周期性对称CFD模型,并利用有限体积法对流场的温度和压力进行计算分析;然后利用扫描电镜对工作叶片的表面形貌进行观测,分析叶片表面微缺陷形式;最后根据仿真与试验观测结果,分析了叶片缺陷产生的原因和影响叶片表面微结构变化的因素。结果表明:叶片前缘温度达到最高的860K,在几何结构和波系的共同作用下,叶片前后缘、叶尖、叶根附近流场流动特性复杂,流道内温度和压力分布不均匀;叶片后缘根部出现长约180μm的穿晶/沿晶混合模式的微裂纹,后缘叶尖处有长约30μm的夹杂物裂纹出现,这是叶片热应力、叶片表面金相转变、氧化、氢脆等共同作用的结果;应根据涡轮泵的实际任务情况对涡轮泵地面热试车程序进行合理的安排,尤其在关机阶段要考虑是否对涡轮叶片的冷却采取大气环境隔离措施。研究可为液体火箭发动机涡轮叶片寿命评估提供参考。The flow field simulation and scanning electron microscope observation methods are used to analyze the surface micro-morphology of a certain type of turbine blade before and after operation,and the effect of high temperature and high pressure environment on the surface morphology of the blade is investigated.First,in order to improve the calculation efficiency,according to the blade form,a periodic symmetric CFD model of the turbine blade flow field is established,and the temperature and pressure of the flow field are calculated and analyzed by the finite volume method.Then,the surface of the working blade is measured by scanning electron microscope.The morphology is observed to analyze the form of micro-defects on the blade surface.Finally,based on the results of simulation and experimental observations,the reasons for the blade defects and the factors affecting the changes of the blade surface microstructure are analyzed.The results show that the temperature of the leading edge of the blade reaches the highest 860 K.Under the combined effect of geometric structure and wave system,the flow characteristics of the flow field near the leading and trailing edge,blade tip,and hub are complicated,and the temperature and pressure distribution in the flow channel is inhomogeneous.The hub near the trailing edge of the blade appears with a cross-grain/inter-grain mixed mode of microcracks about 180μm in length,and an inclusion crack with a length of about 30μm appears at the tip of the trailing edge.This is due to the thermal stress of the blade,the metallographic transformation of the blade surface,and the oxidation,hydrogen embrittlement and other effects.According to the actual task of the turbopump,the turbopump ground hot test program should be reasonably arranged,especially in the shutdown stage,consider whether to take atmospheric environmental isolation measures for the cooling of the turbine blades.The current work can provide a reference for the life evaluation of liquid rocket engine turbine blades.

关 键 词：涡轮叶片 扫描电镜 表面形貌 工作寿命 流场仿真 

分 类 号：V43421[航空宇航科学与技术—航空宇航推进理论与工程]