ABSTRACT During the extraction of magnesium by the electrothermal process, the condensation of magnesium vapours in the condenser is critical to achieve operational efficiency. In the present work, a mathematical heat transfer model has been developed to predict the growth rate of a single liquid metal drop during dropwise condensation (DWC) of magnesium vapours in the electrothermal process. Homogeneous DWC model has been developed considering negligible thermal resistance at the liquid–vapour interface for a single cycle of liquid magnesium layer formed at vapour–liquid interface. The heterogeneous DWC has been modelled taking into account all possible thermal resistances. The role of constriction resistance on transient droplet growth behaviour has been studied and the parametric sensitivity analysis has been conducted. Parameters i.e. degree of undercooling (ΔT), contact angle (θ), thickness of condenser wall (δ )and constriction effect cause (β) has been studied for droplet growth behaviour. Heat transfer and specially the constriction resistance was found to be quite significant for heterogeneous DWC of magnesium metal vapours. Alongwith other parameters, the thermally inactive region (β) on the condenser surface inversely affects the growth. The model-based predicted Mg droplet growth profiles during condensation have been validated with published data on similar DWC studies.

中文翻译：

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镁电热生产中镁蒸气滴冷凝行为的传热模拟

摘要 在通过电热工艺提取镁的过程中，冷凝器中镁蒸气的冷凝对于实现运行效率至关重要。在目前的工作中，已经开发了一种数学传热模型来预测在电热过程中镁蒸气的逐滴冷凝 (DWC) 过程中单个液态金属液滴的生长速率。考虑到在汽-液界面形成的液态镁层的单个循环在液-汽界面的热阻可以忽略不计，开发了均质 DWC 模型。考虑到所有可能的热阻，对异构 DWC 进行了建模。研究了压缩阻力对瞬态液滴生长行为的作用，并进行了参数敏感性分析。参数即 已经研究了过冷度 (ΔT)、接触角 (θ)、冷凝器壁厚 (δ) 和收缩效应原因 (β) 的液滴生长行为。发现传热特别是收缩阻力对于镁金属蒸气的异质 DWC 非常重要。与其他参数一起，冷凝器表面上的热非活性区域 (β) 对生长产生负面影响。冷凝过程中基于模型的预测 Mg 液滴生长曲线已通过类似 DWC 研究的已发表数据得到验证。与其他参数一起，冷凝器表面上的热非活性区域 (β) 对生长产生负面影响。冷凝过程中基于模型的预测 Mg 液滴生长曲线已通过类似 DWC 研究的已发表数据得到验证。与其他参数一起，冷凝器表面上的热非活性区域 (β) 对生长产生负面影响。冷凝过程中基于模型的预测 Mg 液滴生长曲线已通过类似 DWC 研究的已发表数据得到验证。