Research Initiation Award: The Intertube Falling-Film Mode,Its Transition, Hysteresis, and Effect on Heat Transfer

当下降液膜从一个水平管流到 另一个在它下面，它的模式（液滴，射流或片材）具有 对流体动力学和热传递的显著影响。 没有完整的模型或经验基础来预测 降膜模式、其过渡或效果。 的 建议的研究旨在了解哪些物理 参数控制模式及其转换，量化 模式和热传递之间的耦合，并提供 预测模式行为的完整基础。 在这个实验程序中，液体薄膜福尔斯落在两个 加热或冷却的样品管， 环境 测量薄膜位置、厚度和 速度，沿着测量周围的蒸汽 温度、压力、速度和热传递， 表征降膜及其影响。 实验 采用不同的工作介质、管径和 间距，并在静态和强制流动，具有不同的热量 通量、液体质量流率和热力学条件。 检查候选参数对 过渡和滞后。 模式与 传热学进行了研究，制定了评价的基础 模式及其影响。

When a falling liquid film flows from one horizontal tube to another below it, its mode (droplets, jets, or a sheet) has a significant impact on the hydrodynamics and heat transfer. There is no complete model or empirical basis for predicting the falling-film mode, its transitions, or effects. The proposed research is directed at understanding which physical parameters govern the mode and its transitions, quantifying the coupling between mode and heat transfer, and providing a complete basis for predicting mode behavior. In this experimental program, a liquid film falls between two heated or cooled specimen tubes in a thermally controlled environment. Measurements of film location, thickness, and velocity, along with measurements of the surrounding vapor temperature, pressure, velocity, and heat transfer, characterize the falling film and its influence. Experiments are conducted with different working media, tube diameters and spacings, and in quiescent and forced flows, with varying heat fluxes, liquid mass flow rates, and thermodynamic conditions. Candidate parameters are examined for their influence on transitions and hysteresis. Coupling between the mode and heat transfer are studied, to develop a basis for evaluating the mode and its effects.