Pressurized Thermal Shock (PTS) in the Reactor Pressure Vessel (RPV) can occurs during injection of Emergency Core Cooling (ECC) water into the cold leg of Pressurized Water Reactor. Injected ECC water generates large temperature gradient which leads to large thermal stresses in the RPV wall. To study this behaviour in Rossendorf Coolant Mixing Model (ROCOM), case of buoyancy driven mixing with a constant flow rate and 10% density difference between the ECC injection and loop water was taken for analysis. ROCOM is a 1:5 scaled German KONVOI type reactor having four-loop with a RPV mock-up made of transparent acrylic material. Large Eddy Simulation (LES) and Reynolds Averaged Navier–Stokes equations (RANS) based models are used for this numerical analysis work in OpenFOAM CFD code. LES offered more accurate predictions of the local and spatial mixing phenomena compared to RANS based models. The predicted results are compared and validated with experimental data of ROCOM test facility. It shows that results are in good agreement.

反应堆压力容器（RPV）中的加压热冲击（PTS）可能会在将紧急堆芯冷却（ECC）水注入到加压水反应堆的冷段中时发生。注入的ECC水会产生较大的温度梯度，从而导致RPV壁中存在较大的热应力。为了在Rossendorf冷却液混合模型（ROCOM）中研究此行为，以浮力驱动的混合情况为例，以恒定流速和ECC注入与回路水之间的密度差为10％进行分析。ROCOM是比例为1：5的德国KONVOI型反应器，具有四回路，RPV模型由透明丙烯酸材料制成。基于大型涡模拟（LES）和雷诺平均Navier–Stokes方程（RANS）的模型在OpenFOAM CFD代码中用于此数值分析工作。与基于RANS的模型相比，LES提供了对本地和空间混合现象的更准确的预测。将预测结果与ROCOM测试设备的实验数据进行比较和验证。结果表明，结果吻合良好。