基于RELAP5的C型管束外沸腾换热特性模拟分析

Boiling Heat Transfer Simulation Analysis over Type-C Bundle Based on RELAP5

以浸没在大水箱内的C型换热管束为研究对象,采用RELAP5对其换热过程进行模拟计算。C型管束外围设置了虚拟套管和径向流动接管,用于模拟水箱中的自然对流换热过程。为了考察RELAP5模拟C型管束外的沸腾换热性能,分别在给定冷凝压力和给定内壁面热流密度边界条件下进行模拟计算。通过与实验结果的对比可知,模型中加入虚拟套管是必要的,可提高数值计算计算精度,同时RELAP5可有效计算出C型管束各部分换热差异,但换热系数计算值偏小,热流密度12~120 kW/m^(2)范围内最大相差30%。

The type-C bundle in a water tank is simulated by RELAP5.An annular and cross-flow are added in the model to calculate nature convection.To study the heat transfer characteristics,two kinds of boundary are given,which are the condensing pressure and inner heat flux.Compared with the experimental results,it s useful to build an annular outside the bundle,which can improve the calculation accuracy.The heat transfer difference of each part of type-C bundle can be given by the RELAP5 calculation result.However,the computational heat transfer rates are smaller than the experimental results.The maximum difference is 30%in the range of 12~120 kW/m^(2).