摘要
本文通过建立多相流动和传热传质耦合的二维CFD模型,对湿空气中水蒸气与水直接接触时的冷凝速率进行了数值模拟研究,分析了入口空气参数以及水面温度等因素对湿空气冷凝速率的影响。结果表明:较高的空气流速能够获得更大的冷凝速率,但空气流速较低时冷凝效率更高;壁面温度存在与空气温度和相对湿度相关的临界点,当小于临界点后,冷凝速率基本不再增加,临界壁面温度主要和主流空气的温度及相对湿度有关,与空气流速几乎无关。这些结论为尽可能获得更高的冷凝速率提供合理的参数选择。
Based on a two-dimensional multiphase flow CFD model coupled with heat and mass transfer, the condensation rate of water vapor in the moist air which contact directly with cold water was investigated in this paper. The influences of air parameters and water temperature on the condensation rate were also analyzed. The simulation results revealed that, the higher air velocity results in, the higher condensation rate, but the condensation efficiency is higher at lower air velocity. It was also found that, the wall temperature exists a critical point which is mainly related to air temperature and relative humidity, and the condensation rate will almost no longer increase when wall temperature is lower than the critical point. These conclusions are instructive to select reasonable parameters for the improvement of condensation rate.
引文
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