Nucleation and Critical Heat Flux in Spray Cooling

摘要建议书编号：CTS 9813595首席研究员：周黎明，陈荣华该奖项旨在研究喷雾冷却的基本过程。在之前的一项研究中，PIS开发了一种半透明的合成钻石加热器，可以在水和FC-72中产生临界热流。有了这个加热器，泡泡的历史可以被记录在视频上。这项工作将阐明成核、二次成核和通过撞击喷雾液滴过早去除气泡对换热和临界热流密度的影响。这将通过使用视频成像系统测量加热器表面上的气泡生长速度、气泡大小和气泡数量来实现。这项研究将把成核与质量流量、液滴大小和数密度的喷雾特性相关联。对表面成核和二次成核的相对重要性的估计将提高对喷雾过程的理解，并为今后的工作提供基准数据。

ABSTRACT Proposal Number: CTS 9813595 Principal Investigator: L. Chow, R-H Chen This award is to investigate the fundamental processes involved in spray cooling. In a previous study, the PIs developed a semi-transparent synthetic-diamond heater which could produce critical heat fluxes in water and FC-72. With this heater, bubble histories could be recorded on video. The proposed work will clarify the effects of nucleation, secondary nucleation, and premature bubble removal by impinging spray droplets on the heat transfer and the critical heat flux. This will be done by measuring bubble growth rate, bubble size, and bubble population across the heater surface using the video imaging system. The study will correlate nucleation with the spray characteristics of mass flow rate, droplet size and number density. Estimations of the relative significance of surface and secondary nucleation will improve the understanding of the spray process and provide benchmark data for future work.