摘要
以某型燃气轮机透平第1级静叶(无气膜)为研究对象,基于OpenFOAM平台采用叶栅三维黏性流的数值计算方法,研究了不同进口来流湍流度下静叶片表面的压力分布和对流传热系数的分布特征及二者对叶片冷却结构设计的影响。结果表明:来流湍流度对叶片表面的压力分布影响较小,对表面传热影响显著。叶片外表面传热系数随来流湍流度的增大而升高,但增强的幅度逐渐减小。在前缘区的传热增强程度最大达到30%,压力面的影响达15%,吸力面及尾缘区域传热增强程度受湍流度影响约5%。沿叶高方向,叶片传热呈现较高的二维性,叶片根部区域有明显端部效应。根据叶片一维传热过程模拟,若前缘外传热恶化程度达30%,则金属表面局部平均温度上升最大幅度约24 K,这极大影响了叶片寿命。在设计叶片冷却结构时,需要合理地考虑来流湍流度的影响,采用高性能冷却结构并留有适当安全裕度,防止叶片局部过热或产生较大热应力。研究成果可为透平叶片冷却结构设计及现有机组性能优化提供参考。
Based on the OpenFOAM platform,the three-dimensional viscous flow numerical calculation method of cascade is used to study the first stage stator blades without film cooling of a gas turbine.The distribution characteristics of pressure and heat transfer coefficient on the blade surface under different inlet turbulence intensities are studied,and their effect on the cooling structure design of the blade are also analyzed.The results show that the turbulence intensity has little effect on the pressure distribution on the blade surface while it has significant effect on the heat transfer.The heat transfer coefficient increases with the increase of turbulence intensity,but the enhancement amplitude gradually decreases.In the leading edge area,the heat transfer enhancement is up to 30%,the impact on the pressure surface is 15%,and the influence of turbulence on suction surface and trailing edge area is about 5%.In the direction of blade height,the heat transfer of the blade is two-dimensional,and the end effect is obvious in the blade root area.According to the one-dimensional simulation,if the heat transfer outside the leading edge deteriorates by 30%,the local average temperature on the metal surface would increase by about 24 K,which would greatly affect the life of blade.So it is necessary to consider the influence of the inlet turbulence intensity reasonably in the design of the cooling structure.It’s wise to choose the high performance cooling structure,and the blade can be prevented from overheating or overlarge thermal stress with proper safety margin.The research results can provide reference for the design of cooling structure of turbine blades and the optimization of performance in present units.
作者
张祎
陈挺
谈芦益
ZHANG Yi;CHEN Ting;TAN Luyi(Shanghai Electric Power Generation Group,Shanghai 201199,China)
出处
《热力透平》
2022年第1期41-45,68,共6页
Thermal Turbine
