基于多孔介质和等效热导率模型的快堆乏燃料组件传热特性数值分析

乏燃料组件在运输或转运过程中，组件会裸露在传热较差的气体介质内，需关注其散热性能。为模拟乏燃料组件的传热特性，采用多孔介质模型模拟组件的流动阻力，并利用等效热导率模型模拟组件内部的传热。由于自然对流条件下乏燃料组件内部流动符合层流假设，在多孔介质阻力模型中忽略了惯性力项的作用。将等效热导率模型的模拟结果与SNL-LMFBR实验结果进行对比，证明了该模拟方法的有效性。计算结果表明，在水平放置工况下乏燃料组件温度轴向呈对称分布，在竖直放置工况下轴向呈非对称分布，乏燃料组件的高温区域向组件上方偏移。

Numerical Analysis of Heat Transfer Characteristic of Fast Reactor Spent Fuel Assembly Based on Porous Media and Effective Thermal Conductivity Models

During the shipping or transportation processes of the spent fuel assemblies, assemblies will be exposed to the gas region which has bad heat transfer characteristics, so the optimal properties should be focused on. In order to simulate the heat transfer characteristics of spent fuel assembly, the porous media model was used to simulate the flow resistance of spent fuel assembly, and the effective thermal conductivity model was used to simulate the heat transfer. The flow of fluid inside the spent fuel assembly was subjected to the laminar flow hypothesis under natural circulation conditions, so the impact of inertial force in the source of resistance was ignored. The effective thermal conductivity model was validated by comparing the simulation results with experiment data from SNL-LMFBR experiment. The calculation results show that under the horizontal placement condition, the temperature distribution curves of the spent fuel assembly are symmetrical. The asymmetrical distribution is presented under the vertical placement condition, and the high temperature region is shifted to the higher region of the spent fuel assembly.