Collaborative Research: ISS: Revealing interfacial stability, thermal transport and transient effects in film evaporation in microgravity

合作研究：ISS：揭示微重力下薄膜蒸发的界面稳定性、热传输和瞬态效应

• 批准号: 2224417
• 负责人: James Hermanson
• 金额: $ 33.28万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-10-01 至 2026-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2224417&HistoricalAwards=false
• 关键词: Collaborative; Research; ISS; Revealing; interfacial

Evaporation at the surface of a liquid film is critical to many industrial processes including coatings, semiconductor crystal growth, surface texturing in magnetic storage devices, surface finish during paper production, polymer processing, and electrode manufacturing for fuel cells. These applications depend on volatility-induced evaporation (no applied heat). Many other evaporation applications involve heating a solid substrate such as cooling, drying, fuel vaporization, food processing, chemical manufacturing and pharmaceuticals. Evaporation is also used for self-assembly of particles and morphological control of porous structures. Many space-based thermal management systems also depend on evaporation. Despite this ubiquity, the current understanding of film-evaporation processes is incomplete. The unsteady motion at the film surface and the motion of the liquid within the films drastically affect evaporation rates and heat transfer, particularly during transient, or unsteady, evaporation. The overarching goal of this research is to probe the fundamental mechanisms of these complex phenomena by conducting detailed experiments and numerical analysis of evaporating films in both normal- and microgravity conditions. The improved understanding of evaporation processes resulting from this effort may have broad impact in numerous practical applications. This project will use the unique capabilities of the ISS for long-duration microgravity testing to develop a more complete understanding of the behavior of evaporating films by revealing physical mechanisms normally masked under terrestrial conditions. Specific scientific objectives include determining: (i) the transitions between long-wave and short-wave surface instabilities in evaporating films, (ii) the evolution of the convective structures from the onset of evaporation to steady-state, and (iii) the corresponding impacts on thermal transport. Evaporation rates will be controlled using a combination of external heat addition and impulsively changing the system pressure. Diagnostic techniques include ultrasonic film thickness measurements, optical imaging, and thermal and pressure measurements. The stability of evaporating films will be examined by linear stability analysis and Recurrence Quantification Analysis. The latter is a relatively new diagnostic technique that provides metrics such as the rates and trapping-times that measure the recurrence of interfacial film states and their duration. The extraction of these quantitative signatures of film events can serve as triggers for “early warning systems” to predict and control emergent film behavior. The new, detailed information resulting from this investigation will be transformative in that it will lead to fundamental understanding of the origins and nature of the complex mechanisms that impact the liquid film behavior and the rate of heat transfer in evaporating films.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.

液膜表面上的蒸发对于许多工业过程至关重要，包括涂层，半导体晶体生长，磁性存储设备中的表面纹理，纸张生产过程中的表面饰面，聚合物加工和燃料电池的电极制造。这些应用取决于挥发性引起的经济性（无施加热量）。许多其他蒸发应用涉及加热固体底物，例如冷却，干燥，燃料分散，食物加工，化学制造和药品。蒸发还用于自我组装颗粒和多孔结构的形态控制。许多基于空间的热管理系统也取决于蒸发。尽管存在这种无处不在，但目前对膜蒸发过程的理解却是不完整的。膜表面的不稳定运动以及膜中液体的运动剧烈影响经济速度和传热，尤其是在短暂或不稳定的蒸发期间。这项研究的总体目的是通过对正常和微重力条件下的蒸发膜进行详细的实验和数值分析来探测这些复杂现象的基本机制。对这项工作产生的蒸发过程的了解可能对众多实际应用产生广泛的影响。该项目将利用ISS的独特功能进行长期微重力测试，通过揭示通常在陆地条件下掩盖的物理机制，从而更完整地了解蒸发膜的行为。特定的科学对象包括确定：（i）蒸发膜中长波和短波表面不稳定性之间的过渡，（ii）对流结构从蒸发开始到稳态，以及（iii）对热运输的相应影响。蒸发率将通过外部加热和冲动改变系统压力的组合来控制蒸发率。诊断技术包括超声膜厚度测量，光学成像以及热和压力测量。蒸发膜的稳定性将通过线性稳定性分析和复发定量分析来检查。后者是一种相对新的诊断技术，可提供指标，例如衡量界面膜状态及其持续时间的速率和捕获时间。这些膜事件的定量特征的提取可以作为预测和控制紧急膜行为的“预警系统”的触发器。这项投资产生的新的，详细的信息将具有变革性的影响，因为它将对影响液体膜行为的复杂机制的起源和性质进行基本理解，这些机制的起源和性质和性质在蒸发电影中的液体膜行为以及热传递速度。这奖反映了NSF的法定任务，并且通过使用基金会的知识优点和广泛的范围来评估，我们被认为是通过评估来诚实的。