飞机发动机冷气道与隔热层的耦合传热分析

数值研究了某飞机发动机外侧冷气道与隔热层的耦合传热过程。采用低雷诺数k-ε模型与SIMPLEC算法计算通道内可压缩变物性气流的湍流对流换热,采用蒙特卡罗法求解通道壁面间的辐射换热。通道内气流湍流对流换热、壁面间辐射换热与隔热层内导热耦合求解。通过模拟计算,分析了通道与隔热层的耦合传热机制,考察了相关参数的影响。结果表明,在所考虑的通道结构与空气流条件下,冷气道外环壁面的温度高于气流温度,气流对内外环壁面均起冷却作用;在隔热层参数不变条件下,壁面间的辐射换热与气流的对流冷却是该传热过程的控制机制,增大冷气流量、降低壁面发射率均可显著降低隔热层的外壁面温度。

Analysis of Coupled Heat Transfer in Air Cooling Channel of Aeroengine and Thermal Isolation Layer

The coupled heat transfer in the air cooling channel and thermal isolation layer of an aeroengine is investigated numerically. The low Re number k-ε turbulence model and the SIMPLEC algorithm are employed to simulate the turbulent convection of compressible airflow with variable properties. The wall radiation heat transfer is solved by the Monte Carlo method. The turbulent convection and wall radiation in channel and the thermal conduction in isolation layer are solved simultaneously. By analyzing the numerical results, the mechanism governing the coupled heat transfer and the effects of relevant parameters are discussed. The investigation shows that, under the considered channel and airflow conditions, the outerwall temperature is higher than that of airflow, so both walls are cooled by the airflow. For constant thermal parameters of the isolation layer, the wall radiation and the airflow cooling govern the heat transfer process. Increasing the airflow rate or decreasing the wall emissvities can obviously reduce the outside temperature of isolation layer.