This paper discusses about the effect of feeder height and heat flux on the heat transfer characteristics of horizontal tube falling film evaporation in the thermal regimes. In order to investigate this, a two- dimensional CFD model was developed to perform simulation and results were compared and validated with published data available in the literature. Heat transfer co-efficients in the thermal regimes were determined from the CFD simulation and the results were recorded, analyzed and validated with the mathematical models available in the literature. The novelty of the current study is to predict the commencement of the fully developed thermal region over the tube from the simulation model under varying feeder height and heat flux. An effort was also made to measure the liquid film thickness around the tube from the CFD model in the thermal regimes. It is observed that angle of thermally developing region contracts and fully developed thermal region extends with the increase of the feeder height and heat flux. It is observed from the study that increase of heat flux by 10 kW/m² resulted in increase of heat transfer co-efficient value by 10–12% average in thermally developing region and 12–15% average in fully developed region. Thinnest liquid film thickness observed between 85 and 127°angle. Shifting of thinnest region of liquid film upward from the mid tube with the increase of the feeder height and heat flux is noted.

本文讨论了在热态下进料器高度和热通量对水平管降膜蒸发的传热特性的影响。为了对此进行研究，开发了一个二维CFD模型进行仿真，并使用文献中的公开数据对结果进行了比较和验证。通过CFD模拟确定了热态下的传热系数，并使用文献中提供的数学模型对结果进行了记录，分析和验证。当前研究的新颖之处在于，在变化的进料器高度和热通量的情况下，通过模拟模型来预测管子上完全展开的热区的开始。还努力根据热工况下的CFD模型测量管周围的液膜厚度。可以观察到，随着进料器高度和热通量的增加，热显影区域的角度缩小，并且完全显影的热区域延伸。从研究中观察到，热通量增加了10 kW / m²导致热传导区域的传热系数值平均增加10–12％，完全发达区域的传热系数值平均增加12–15％。在85至127°角之间观察到的最薄液膜厚度。随着送料器高度和热通量的增加，注意到液膜的最薄区域从中管向上移动。