环形散热器的动态性能

 利用热阻热容概念近似描述环形散热器微元段上的动态特性,加上热平衡条件,从而推导出整个环形散热器动态数学模型。只要在微元段上选取适当的节点数,该模型就可以满足任意精度之要求。借助于计算机并使用有限差分法,对环形散热器的动态性能进行了数值计算,理论计算结果与空中飞行试验数据吻合较好。还给出了环形散热器芯体在某一状态下的温度分布,作为动态响应计算的特例,最后计算了此状态下环形散热器稳态性能,其结果与对应的试飞数据比较令人非常满意。

DYNAMIC PERFORMANCE OF THE ANNULAR HEAT EXCHANGER

This paper applies the concept of thermal resistors and capacitors to describe approximately the dynamic behavior of the section with the thickmess of the annular heat exchanger in axial direction, i.e. the section is converted to lumped thermal capacities connected by thermal resistors. The number and size of lumps are determined by the accuracy requirements of the problem and temperature gradients . Then, based on the principle of heat balance, the mathematical model is established. The dynamic performance is obtained by the finite-differences approach . It is possible to consider such problems as change of state, variable thermodynamic properties and arbitrary variable boundary condition. As an example, the paper analyze the dynamic performance of the annular heat exchanger of the environmental control system in the aircraft. It has shown that there is a good agreement between the numerical results with the flight test data. The paper also presents the steady performance and the core temperature distribution in the given condition.