Nucleation and Critical Heat Flux in Spray Cooling

摘要 提案编号：CTS 9813595 主要研究者：L.周仁宏 该奖项旨在研究喷雾冷却中涉及的基本过程。 在之前的研究中，PI开发了一种半透明的合成金刚石加热器，可以在水和FC-72中产生临界热通量。 有了这个加热器，气泡的历史可以记录在视频上。 本研究将探讨喷雾液滴碰撞对成核、二次成核及气泡过早去除之影响。 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率、气泡尺寸和气泡数量来完成。 研究将关联成核与喷雾特性的质量流量，液滴尺寸和数量密度。 表面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，并为未来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.