Argon covering the free surface of the pool-type sodium-cooled fast reactor may be mixed into the coolant in form of entrainment bubbles due to the fluctuation of liquid surface, which introduces positive reactivity to the core, reduces the heat exchange capacity of the core and intermediate heat exchangers (IHXs), and possibly leads to the cavitation of the primary sodium pump (PSP), threatening the safe operation of the reactor. In this study, the computational fluid dynamics (CFD) simulation of liquid sodium fall entrained argon was carried out based on the Volume of Fluid (VOF) interface tracking method to describe the entrainment process in detail, and the influences of geometry size, initial liquid level height and inlet velocity on entrainment were analyzed successively. It was found that the re-submergence velocity, having a linear relation with the re-submergence angle, is the key factor of the liquid fall type gas entrainment. It can be used to judge whether the liquid fall type entrainment occurs conservatively. In addition, the parameters affecting the re-submergence velocity are specifically analyzed from the supplementary cases, according to the results of which, the empirical relation of the re-submergence velocity is obtained. Therefore, the situation of liquid fall type gas entrainment under various working conditions can be predicted numerically.

由于液面的波动，覆盖池型钠冷快堆自由表面的氩气可能以夹带气泡的形式混入冷却剂中，从而对堆芯产生正反应性，降低了堆芯的热交换能力和中间热交换器（IHX），并可能导致主钠泵（PSP）发生气蚀，从而威胁到反应堆的安全运行。本研究基于液体体积（VOF）界面跟踪方法对液态钠下落夹带氩气进行了计算流体动力学（CFD）模拟，详细描述了夹带过程，以及几何尺寸，初始液体的影响。依次分析了夹带的水平高度和入口速度。发现再淹没速度，与再浸入角呈线性关系，是液体掉落型气体夹带的关键因素。可以用来判断是否保守地发生了液体掉落型夹带。另外，从补充案例中具体分析了影响再入水速度的参数，根据结果，得出了再入水速度的经验关系。因此，可以数值地预测在各种工作条件下液体掉入型气体的夹带情况。根据其结果，获得了再浸入速度的经验关系。因此，可以数值地预测在各种工作条件下液体掉入型气体的夹带情况。根据其结果，获得了再浸入速度的经验关系。因此，可以数值地预测在各种工作条件下液体掉入型气体的夹带情况。