涡轮发动机高温隔热涂层内的传热研究

高温环境中的金属部件, 通常采用表面涂层技术以降低金属材料的温度和热力梯度。氧化锆、陶瓷等涂层材料对热辐射是半透明的, 因此, 高温下涡轮发动机的热分析需要考虑涂层内辐射换热的影响。本文考虑了各种界面辐射特性: 不透明界面和半透明界面, 镜反射和漫反射。采用光线踪迹 /节点分析法计算了吸收、各向同性散射性介质内的辐射传递系数。结合控制容积法数值模拟了涡轮叶片和燃烧室衬垫涂层内的辐射与导热瞬态耦合换热。 

Heat Transfer in Translucent Thermal Barrier Coatings of Turbine Engine

Some of thermal barrier materials for coating in aeroengine,such as zirconia and ceramic,are partially transparent to thermal radiation.So it is necessary to estimate quantitatively the radiation effect in the thermal analysis of turbine engine under high temperature.In this paper,various surface radiative characteristics are considered including opaque (with soot) and semitransparent (without soot) coating surfaces,specular and diffuse reflections.The radiative transfer coefficients of the absorbing and isotropic scattering coatings are derived by the ray tracing/node analysis method.The transient coupled radiative and conductive heat transfer in the coatings are numerically simulated by the radiative transfer coefficients in combination with the full implicit control volume method.The radiative properties of the coatings are modelled by two or four spectral bands.The analysis includes the effects of the opaque surface emissivity,the coating thickness,and the surface radiative characteristics on the temperature distributions and heat flux densities.