Miscibility-immiscibility conundrum in air-liquid-vapor flow modeling: Bridging the gap by using the phase-field method

空气、液态水和水蒸气的混合物在自然界和工程过程中无处不在。这些混合物发生在能源产生、船舶运输、吸入药物治疗和大气中云的形成中。目前，还没有一个通用的理论来描述这些混合物的流体动力学行为，这限制了科学技术的广泛进步。这项研究将建立一个基于第一性原理的计算模型，为理解空气、液态水和水蒸气混合物的物理学提供一个理论框架。研究人员将使用高度控制的实验来提供物理见解并验证计算方法。这项研究将在工程，数学和物理的界面上提供跨学科的进步。这项研究的广泛影响将由外联和教育活动补充。这些举措包括重塑流体力学向本科生介绍的方式，以及为STEM领域中代表性不足的群体招募和保留活动。由于混相、惯性力、粘性力和表面张力的相互作用所产生的迷人的物理特性，多相流动力学受到了科学界的极大关注。虽然在理解单组分两相流（例如，单一化学物质的蒸发和冷凝）和单相两组分流（例如，由空气和水组成的气泡流）方面取得了重大进展，但同时涉及两相两组分的流动动力学还没有得到很好的理解。该项目将开发一种新的基于第一性原理的计算模型，该模型可以捕获与空气、液态水和水蒸气流动相关的所有物理因素。该模型将通过最先进的实验来验证界面动力学、速度和压力场的三维监测。该模型将基于相场理论，该理论允许在混相（空气和水蒸气）和非混相（空气和液态水）混合物之间自然过渡，提供了一个理想的理论框架。在这个项目中进行的综合计算和实验研究有望使我们研究空气、液态水和水蒸气流动的能力实现飞跃，并将为众多工程和科学应用的变革进步提供支持工具。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Mixtures of air, liquid water, and water vapor are ubiquitous in nature and in engineering processes. These mixtures occur in energy generation, transport of marine vehicles, inhalation drug therapies, and in cloud formation in the atmosphere. Currently, there is no general theory to describe the fluid dynamics behavior of these mixtures, which limits a wide range of scientific and technological advances. This research will develop a first-principles-based computational model that will provide a theoretical framework for understanding the physics of air, liquid water, and water vapor mixtures. The investigators will use highly controlled experiments to provide physical insights and validate the computational method. This research will deliver interdisciplinary advancements at the interface of engineering, mathematics, and physics. The research broader impacts will be complemented by outreach and educational activities. These include an initiative to reshape the way fluid mechanics is introduced to undergraduate students and recruiting and retention activities for groups that are underrepresented in STEM fields.Multiphase flow dynamics has received significant attention from the scientific community due to the captivating physics produced by the interplay of miscibility, inertial forces, viscous forces, and surface tension. While there has been significant progress in understanding single-component, two-phase flows (e.g., vaporization and condensation of a single chemical species), and single-phase, two-component flows (for example, bubbly flows composed of air and water), the dynamics of flows involving simultaneously two phases and two components are not well understood. This project will develop a new first-principles-based computational model that captures all physical factors relevant to air, liquid water, and water vapor flows. The model will be validated through state-of-the-art experiments monitoring the interface dynamics, velocity and pressure fields in three dimensions. The model will be based on the phase-field theory that allows a natural transition between miscible (air and water vapor) and immiscible (air and liquid water) mixtures, providing an ideal enabling theoretical framework. The integrated computational and experimental research to be developed in this project promises to constitute a leap forward in our ability to investigate flows involving air, liquid water, and water vapor and will provide the enabling tools for transformative advances across numerous engineering and science applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.