局部规则涂层对气冷叶片测温影响的数值研究

为研究微细热电偶测温安装涂层对其测量精度的影响机理,基于气固耦合传热(CHT)方法,建立了接近真实气膜冷却叶片的三维模型,选择SST(shear stress transport) γ -θ湍流模型,对未喷涂氧化铝涂层与在叶片吸力面前缘、压力面前缘、压力面尾缘处喷涂氧化铝涂层后的气冷叶片表面温度进行数值研究。无涂层工况的数值计算结果与实验结果误差控制在5%以下,验证了数值方法的有效性。研究结果表明:涂层对近壁面燃气的流动特性产生显著影响;三种有涂层工况的数值计算结果表明,压力面前缘处比吸力面前缘处温差波幅小,且比压力面尾缘处测温误差降低35.5%;在压力面及吸力面前缘处,最佳测温区域为涂层中部至下端之间的部位,而在压力面尾缘处,最佳测温区域尽量选择靠近涂层上端部位。 

Numerical study on influence of local regular coating on temperature measurement of film-cooled vane

In order to study the influence mechanism of temperature measurement coating on measuring accuracy of fine thermocouple, a three-dimensional model for film-cooled vane was established based on conjugated heat transfer(CHT) method. SST(shear stress transport) γ -θ turbulence model was carried out on the film-cooled vane sprayed with alumina coating on the front edge of suction, front edge of pressure and trailing edge of pressure surface. The error between the numerical results and the experimental results was controlled below 5%, verifying the effectiveness of the numerical method. The results showed that, the coating had a significant effect on the flow characteristics of gas near the wall. However, the numerical results of three coating conditions showed that the temperature difference amplitude at the front edge of pressure was smaller than that at the front edge of suction, and the temperature measurement error was 35.5% lower than that at the trailing edge of pressure. In addition, on the pressure surface and the front edge of suction, the best temperature measurement area was between the middle and the lower end of the coating, while on the trailing edge of the pressure surface, the best temperature measurement area was close to the upper end of the coating.