UNS: Collaborative Research: Numerical and Experimental Study of the Instability Mechanisms and Bubble Growth due to Explosive Boiling

1512093/1511152 Esmaeeli，Asghar/Hermanson，James C.该提案旨在提供非常必要的洞察力，了解非常快速、爆炸性的汽泡增长，与沸水中的汽泡非常相似，但速度更快。这可以通过适当地提供能量并将能量集中在液体上来实现。这一知识的一个潜在应用是，由于气泡的存在并在微尺度上快速增长，它可以帮助设计通常用于小型设备的微尺度致动器。本科生和研究生都将参与这项研究，而K-12学生和他们的老师也将接触到这项研究。PI提出了一种实验和模拟相结合的方法，以(1)确定静止流动中发生爆炸性沸腾的参数范围，并在此条件下，(2)对单个蒸汽核的动态增长有基本的了解，(3)探索多核增长的动力学。目前该领域的研究几乎完全是实验性的，由于实验的复杂性，许多关键方面无法定量探讨。数值模拟将有助于解释实验结果，这些结果将通过高速成像获得，产生亟需的定量见解，并有助于解决涉及快速蒸发的更广泛的工程问题。如果捕捉到气泡生长的动态，它可以通过适当地将能量集中在它发生在微观尺度上的初始生长上而被用作执行器。如果成功的话，这些结果可以提高对微观尺度上以气泡为致动器的能量聚焦现象的理解。同样，它将有助于改进闪蒸雾化器的设计，以及涉及挥发性液体的运输和储存或大规模发电的工艺。

1512093 / 1511152Esmaeeli, Asghar / Hermanson, James C. The proposal aims to provide much needed insight of the very rapid, explosive vapor bubble growth much like those in boiling water but even faster. This can occur by properly providing and focusing energy on liquids. One potential application of this knowledge is that, since the bubble comes into existence and grows fast while at micro-scales, it can help design micro-scale actuators commonly used in small devices. Both undergraduate and graduate will be involved in, while K-12 students and their teachers will also be exposed to, the research.The PIs propose a combined experimental and modeling approach to (1) determine the range of parameters over which explosive boiling in quiescent flows will occur and, under this condition, (2) to gain fundamental understanding of the dynamic growth of a single vapor nucleus, and (3) to explore the dynamics of multi-nuclei growth. Current research in the field is almost exclusively experimental in nature, and many crucial aspects cannot be probed quantitatively due to the complexity of experimentation. The numerical modeling will facilitate interpreting experimental results, which will be acquired using high-speed imaging, yielding much-needed quantitative insights and helping to solve problems over a broader range of engineering problems involving rapid evaporation. If the bubble growth dynamics is captured, it can be used as an actuator by properly focusing energy onto its initial growth that occurs at micro-scales. The results can improve understanding of energy focusing phenomena at the micro-scale involving bubbles as actuators if successful. Similarly, it will help to improve the design of flash-boiling atomizers and the processes involving transport and storage of volatile liquids or large scale energy generation.