State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian, 116024, China.
NO. 6 Academy of CASIC, Huhhot, 010076, China.
Sci Rep. 2017 Apr 20;7(1):987. doi: 10.1038/s41598-017-01190-9.
Condensation is a common physical process which widely exists in natural phenomena and thermal energy systems. In a condensation process, cluster is considered as the important bridge between vapor body and condensates. However, limited by the minimum imaging dimension of traditional measurements, early experimental studies about initial stages of condensation process are not sufficient. This paper provides a powerful optical platform for the study of dynamic clusters process. Based on the Rayleigh law, optical experiments were firstly introduced to investigate the clusters spatial distribution close to and far from condensation surface. The results show that clusters are mainly generated in the vicinity of the condensation surface within the thickness of 200 μm. When they move away from the condensation surface, clusters progressively vanish and they have a life cycle of a fraction of a millisecond. Though scattering intensity is proportional to the 6th power of cluster radius r and cluster number density N theoretically, the scattering intensity does not increase sharply with the increase of subcooling degree from the experimental results, so we can infer that the cluster number density plays a dominate role in this process and the effect of cluster radius almost can be ignored.Zhong Lan and Di Wang contributed equally to this work.
凝结是一种普遍存在于自然现象和热能系统中的物理过程。在凝结过程中，团簇被认为是蒸汽体和凝结物之间的重要桥梁。然而，受传统测量方法最小成像尺寸的限制，早期关于凝结过程初始阶段的实验研究还不够充分。本文提供了一个研究动态团簇过程的强大光学平台。基于瑞利定律，首次引入光学实验来研究靠近和远离凝结表面的团簇空间分布。结果表明，团簇主要在凝结表面附近的 200μm 厚度范围内产生。当它们远离凝结表面时，团簇逐渐消失，它们的生命周期只有几毫秒。虽然从理论上，散射强度与团簇半径 r 和团簇数密度 N 的 6 次方成正比，但从实验结果来看，散射强度并没有随着过冷度的增加而急剧增加，因此我们可以推断出团簇数密度在这个过程中起主导作用，而团簇半径的影响几乎可以忽略不计。Zhong Lan 和 Di Wang 对这项工作贡献相同。
