相变换热适时动态过程数值模拟

Numerical Simulation of a Transient Dynamic Process for Phase-transition Heat Exchange

以冷凝器为例 ,建立了分区和分流型的适时动态分布参数模型 ,模型建立过程中考虑流体的适时物性参数、湿区含液量、流动压力损失以及管壁蓄热等细节 ,使模型的准确性和通用性显著提高。在模拟过程中 ,计算机根据制冷剂状态自动由所建立的物性数据库中查取对应物性参数。模型采用显式方程组 ,求解速度快。由该模型可进行冷凝换热过程非稳态性能研究 ,获得换热过程冷、热流体温度、压力和冷凝状态等随时间变化的过程。通过实验验证表明 。

With a steam condenser serving as a physical model a dynamic model of transient distributed parameters was set up with divided zones and divided flow patterns. During the setting-up of the model some specific details have been taken into account, such as fluid transient physical-property parameters, liquid content in wet zones, flow pressure losses and tube-wall heat accumulation, etc, thereby markedly enhancing the accuracy and usage scope of the model. In the process of simulation a computer can on the basis of a refrigerant condition automatically check and select corresponding physical-property parameters from an established physical-property database. The model adopts an explicit-type equation group, which expedites resolution speed. With the help of the model it is possible to conduct the non-steady performance study of a condensation heat-exchange process, acquiring a time-dependent variation process, such as the cold and hot fluid temperature, pressure and condensation state, etc during a heat-exchange process. By way of an experimental verification it has been shown that the model under discussion features relatively high precision.