高可靠性航空电子设备热分析中的有限体积法

Finite volume method in thermal analysis of avionics

阐述了热对系统可靠性的影响,对比了数值法求解温度场分布的优缺点.针对航空电子设备热分析中同时要求满足高的分析精度和快的计算速度的问题,提出用有限体积法求解温度场分布的计算方法.根据典型航空电子设备的结构特点,建立了温度场的数学模型,给出了边界条件.在此基础上,用有限体积法对待求解方程离散化,给出了离散化过程中网格划分及边界的处理方法.结合实例进行了温度场求解,计算结果与热测量结果进行了对比,得到了较高的分析精度,验证了方法的有效性.最后对计算误差进行了分析,并提出了进一步热设计的合理化建议.

The influence of heat to the system reliability was introduced. The merits and drawback of numerical methods in solving temperature distribution were compared. In order to solve the problem of avionics of high reliability which requires highly precise result and rapidly computational velocity in thermal analysis, a computed approach of the finite volume method （FVM） to solve the temperature distribution was devoloped. The mathematical model of temperature distribution was built based on typical avionics and its boundary condition was given. Then the control equation was discretized by means of the FVM. The mesh division, the process of discretization and the disposal of boundary were included. The temperature distribution was calculated with an example. The comparison between the result of calculation and the result of measurement demonstrates a high precision of thermal analysis. The validity of this method was verified. The reason of calculated error was indicated and a reasonable proposal about further thermal design based on the result was offered in the end.