Steam direct contact condensation (DCC) into subcooled water may be encountered in different important industrial process applications, such as steam jet pumps, steam ejectors, pressurizers, and emergency cooling systems of nuclear reactor core. In this work, a numerical simulation study has been done for injection of steam into a tank full of subcooled water. In the simulations, the Eulerian multiphase flow in addition to a realizable k-epsilon turbulence model has been utilized. Moreover, a DCC model has been used for condensation capturing. Fluent software with a user-defined function (UDF) for the DCC model was employed for simulations. The results obtained from simulations were validated with experimental results, and a fair agreement was observed. This study considered the local Nusselt number (LNN) the most suitable parameter for investigating the heat transfer rate (HTR) at the computational cell level. Therefore, the contours of the LNN, its axial distribution, and radial distribution were studied with respect to the inlet pressure of injected steam, temperature of tank water, and location along the axis of the nozzle. The results reveal the fact that the value of the LNN reaches a maximum at the nozzle exit along the axis of the nozzle at 323 K tank water temperature. LNN decreases by increasing or decreasing the tank water temperature beyond 323 K. It is claimed that the heat transfer (HT) study at such a local scale has been conducted for the first time to the best of our knowledge, and it unfolds various crucial facts regarding steam-water interaction.

中文翻译：

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过冷水注蒸汽传热数值分析


在不同的重要工业过程应用中可能会遇到蒸汽直接接触冷凝（DCC）成过冷水的情况，例如蒸汽喷射泵、蒸汽喷射器、稳压器和核反应堆堆芯的紧急冷却系统。在这项工作中，对将蒸汽注入充满过冷水的水箱进行了数值模拟研究。在模拟中，除了可实现的 k-epsilon 湍流模型之外，还使用了欧拉多相流。此外，DCC 模型已用于冷凝捕获。采用具有用于 DCC 模型的用户定义函数 (UDF) 的 Fluent 软件进行仿真。模拟获得的结果与实验结果进行了验证，并且观察到了相当的一致性。本研究认为局部努塞尔数 (LNN) 是在计算单元级别研究传热率 (HTR) 的最合适参数。因此，根据注入蒸汽的入口压力、罐水温度以及沿喷嘴轴线的位置，研究了LNN的轮廓、轴向分布和径向分布。结果表明，在水箱水温为 323 K 时，沿喷嘴轴线的喷嘴出口处 LNN 值达到最大值。 LNN 通过增加或降低水箱水温超过 323 K 来降低。据称，据我们所知，首次在如此局部范围内进行传热 (HT) 研究，并揭示了各种关键事实关于蒸汽与水的相互作用。