高压涡轮导叶冷却结构对热应变特性的影响

Effects of Cooling Structure on Thermal Strain Characteristic of High-Pressure Turbine Guide Vane

关键词:  涡轮导叶  冷却结构  气热耦合  热应变特性

Key words:  Turbine guide vane  Cooling structure  Conjugate heat transfer  Thermal strain characteristic

摘要:

为了研究燃气轮机起动过程中导叶冷却结构对热应变特性的影响，基于气热耦合的方法，对具有尾缘劈缝冷却结构和叶根排气冷却结构的高压涡轮导叶热应变特性进行数值研究。通过研究导叶的气动特性和传热特性，计算获得导叶表面的对流换热系数，并以换热系数作为热边界条件进行热-结构耦合求解，得到导叶在燃气轮机起动过程中的瞬态热应变场。研究结果表明:燃气轮机起动的前10s以及50s之后，冷却结构对导叶热应变影响较大；劈缝结构导叶的最大热应变比叶根排气结构最大热应变大47%；叶根排气结构热应变特性更优于尾缘劈缝结构。

Abstract:

To research the effects of cooling structure on thermal strain characteristic of vane during the gas turbine start-up period，a numerical simulation based on conjugate heat transfer method was presented to analyze the thermal strain characteristic of high-pressure turbine guide vanes with cooling structures of trailing edge ejection and hub ejection. The surface heat transfer coefficients of guide vane were calculated by analyzing aerodynamic characteristic and heat transfer characteristic of guide vane. The heat transfer coefficients were applied to coupled thermal-structure field as thermal boundary conditions in order to obtain transient thermal strain field during the gas turbine start-up period. The results show that the cooling structure has a significant influence on the thermal strain in the first 10s and after 50s of the gas turbine start-up period. The maximum thermal strain of trailing edge ejection is 47% larger than that of hub ejection. The thermal strain characteristic of hub ejection is superior to that of trailing edge ejection.