The Small Modular Dual Fluid Reactor (SMDFR) is a novel molten salt reactor based on the dual fluid reactor concept, which employs molten salt as fuel and liquid lead/lead-bismuth eutectic (LBE) as coolant. A unique design of this reactor is the distribution zone, which locates under the core and joins the core region with the inlet pipes of molten salt and coolant. Since the distribution zone has a major influence on the heat removal capacity in the core region, the thermal hydraulics characteristics of the distribution zone have to be investigated. This paper focuses on the thermal hydraulics analysis of the distribution zone, which is conducted by the numerical simulation using COMSOL Multiphysics with the CFD (Computational Fluid Dynamics) module and the Heat Transfer module. The energy loss and heat exchange in the distribution zone are also quantitatively analyzed. The velocity and temperature distributions of both molten salt and coolant at the outlet of the distribution zone, as inlet of the core region, are produced. It can be observed that the outlet velocity profiles are proportional in magnitude to the inlet velocity ones with a similar shape. In addition, the results show that the heat transfer in the center region is enhanced due to the velocity distribution, which could compensate the power peak and flatten the temperature distribution for a higher power density.

中文翻译：

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小型双流体反应堆分布区的热力学分析

小型模块化双流体反应堆（SMDFR）是基于双流体反应堆概念的新型熔融盐反应堆，该反应堆使用熔融盐作为燃料，并使用液态铅/铅-铋共晶（LBE）作为冷却剂。该反应器的独特设计是分布区，该分布区位于堆芯下方，并将堆芯区域与熔融盐和冷却剂的进口管连接起来。由于分布区对核心区域的排热能力有重要影响，因此必须研究分布区的热水力特性。本文着重于分布区域的热力水力分析，这是通过使用COMSOL Multiphysics与CFD（计算流体动力学）模块和传热模块进行的数值模拟进行的。还对分布区内的能量损失和热交换进行了定量分析。分布区域出口​​处（作为核心区域的入口）会生成熔融盐和冷却剂的速度和温度分布。可以看出，出口速度曲线的大小与形状相似的入口速度的大小成正比。此外，结果表明，由于速度分布，中心区域的传热得到了增强，这可以补偿功率峰值，并使温度分布趋于平坦，从而获得更高的功率密度。可以看出，出口速度曲线的大小与形状相似的入口速度的大小成正比。此外，结果表明，由于速度分布，中心区域的传热得到了增强，这可以补偿功率峰值，并使温度分布趋于平坦，从而获得更高的功率密度。可以看出，出口速度曲线的大小与形状相似的入口速度的大小成正比。此外，结果表明，由于速度分布，中心区域的传热得到了增强，这可以补偿功率峰值，并使温度分布趋于平坦，从而获得更高的功率密度。