The Atomic Detail of Evaporating Menisci

项目编号：csts -0437583项目负责人：Freund， Jonathan b .合作院校：伊利诺伊大学厄巴纳-香槟分校项目名称：半月板蒸发的原子细节发生在固体-液体-蒸汽共存的交界处的蒸发，即所谓的三交界处，在多相传热和传质中起着关键作用。在成核和其他相变传热应用中，它占总蒸发质量和热通量的很大一部分。由于结通常是表面上薄液体膜的端点，它的行为改变了整个薄膜的动力学。蒸发和沸腾的建模主要是使用具有经验闭包的连续统模型来处理的。有前途的连续模型的三结已经发展，如耦合流体力学动力学。实验结果令人鼓舞。众所周知，在最薄的液体区域，如蒸发半月板，额外的分子效应将变得重要。该项目将首次进行固体-液体-蒸汽-三结附近蒸发半月板的原子模拟，以观察其原子细节。在三结中，将进行亚尺度聚焦原子模拟，以研究统一半月板模型中使用的局部流动和流体特性，即粘度、表面张力、导热性和蒸发动力学。原子模拟将在PI先前开发的连续润滑模型的背景下进行解释，然后对整个半月板模型进行改进，并针对蒸发半月板的全尺寸原子模拟进行验证。该合同由化学和运输系统分部的热传输和热处理项目资助。

ABSTRACTNational Science FoundationProposal Number: CTS-0437583Principal Investigator: Freund, Jonathan B.Affiliation: University of Illinois-Urbana-ChampaignProposal Title: The atomic detail of evaporating menisciEvaporation that takes place at the junction where a solid-liquid-vapor co-exist, the so-called tri-junction, plays a critical role in multi-phase heat and mass transfer. In nucleate and other phase-change heat transfer applications, it accounts for a significant fraction of the overall evaporative mass and heat flux. Since the junction is frequently the endpoint of a thin liquid film on a surface, its behavior alters the dynamics of the entire thin film. Modeling of evaporation and boiling is primarily handled using continuum models with empirical closures. Promising continuum models of the tri-junction have been developed that couple for example hydrodynamics to kinetics. Agreement with experiment has been encouraging. It is generally known that in the thinnest liquid regions such as evaporating menisci, additional molecular effects will become important. This project will undertake the first ever atomistic simulations of evaporating menisci near solid-liquid -vapor-tri-junctions in order to observe their atomic detail. In the tri-junction, sub-scale focused atomistic simulations will be performed to investigate the local flow and fluid properties used in the unified meniscus model, namely viscosity, surface tension, thermal conductivity, and evaporation kinetics. The atomistic simulations will be interpreted in the context of a continuum lubrication model previously developed by the PI, and improvements to the overall meniscus model will then be made and validated against the full-scale atomistic simulations of the evaporating meniscus. The award has been funded by the Thermal Transport and Thermal Processing Program of the Chemical and Transport Systems Division.