Falling film flow and heat transfer are extensively encountered in various industries of renewable and sustainable energy due to the outstanding heat transfer performance. The predictions in falling film hydrodynamics and heat transfer are crucial for the optimal design of falling film heat exchangers, and there have been considerable advancements made in this area over the past few decades. Considering the gaps in current literature predictions, this paper aims to present a comprehensive review on the correlations of flow pattern transition, film thickness, heat transfer, and liquid film rupture within falling film flowing over horizontal tubes and tube bundles. Through comparisons and summarizations, it can be found that the documented correlations appear to be significantly out of alignment with one another, which greatly restricts the applicability of these predictions. The correlations of falling film thickness that are obtained using regression approach based on dimensional analysis may take into account more factors than the ones modified from Nusselt theory. The predictions of flow pattern transition of falling liquid film with horizontal column are often described as the functions of the film Reynolds number, derived from the Kapitza number or the Galileo number. The functions of Nusselt number, film Reynolds number, Prandtl number, and Archimedes number are typically used to represent sensible and evaporative heat transfer correlations, whereas boiling heat transfer correlations also take into account the influence of heat flux, such as Boiling number. The full process of actual heat transfer is taken into account from both the standpoints of sensible convection and nucleate boiling using the combination functions of various heat transfer forms. Within the ranges of their own parameters, the well-established heat transfer models often offer good accuracy. While the predictions of phase change heat transfer often behave worse, the predictions of sensible heat transfer are more general and accurate. Generally speaking, the minimum film flow rate or the maximum heat flux were the functions that correlated with the inceptions of liquid film rupture.

中文翻译：

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水平管上的降膜流体动力学与传热的相关性：综述

降膜流和传热由于其出色的传热性能，广泛应用于可再生和可持续能源的各个行业。降膜流体动力学和传热的预测对于降膜换热器的优化设计至关重要，并且在过去几十年中该领域取得了相当大的进步。考虑到现有文献预测的差距，本文旨在对流经水平管和管束的降膜内流型转变、膜厚度、传热和液膜破裂的相关性进行全面综述。通过比较和总结，可以发现记录的相关性似乎彼此之间明显不一致，这极大地限制了这些预测的适用性。采用基于量纲分析的回归方法获得的降膜厚度相关性比努塞尔理论修正的降膜厚度相关性可以考虑更多的因素。水平柱下降液膜流型转变的预测通常被描述为源自卡皮查数或伽利略数的膜雷诺数的函数。努塞尔数、薄膜雷诺数、普朗特数和阿基米德数的函数通常用于表示显热和蒸发传热关系，而沸腾传热关系还考虑了热通量的影响，例如沸腾数。利用各种传热形式的组合函数，从显热对流和核态沸腾的角度考虑了实际传热的整个过程。在其自身参数范围内，成熟的传热模型通常具有良好的精度。虽然相变传热的预测通常表现较差，但显热传递的预测更加普遍和准确。一般来说，最小膜流率或最大热通量是与液膜破裂起始相关的函数。