Priority Organization for Innovation and Excellence, Kumamoto University, 2-39-1, Kurokami, Chuo-ku, Kumamoto-shi, Kumamoto, 860-8555, Japan.
Department of Nuclear Engineering, Kyoto University, C3-d2S06, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan.
Sci Rep. 2017 May 24;7(1):2362. doi: 10.1038/s41598-017-02450-4.
In industrial applications involving spray-cooling, combustion, and so on, prediction of the maximum spreading diameter of a droplet impinging on a solid surface permits a quantitative estimation of heat removal and energy consumption. However, although there are many experimental studies regarding droplet impingement behaviour, theoretical models have an applicability limit for predicting the maximum spreading diameter. In the present study, we have developed an analytical model for droplet impingement based on energy conservation that considers adhesion energy in both horizontal and vertical directions at the contact line. The theory is validated by our experiment and existing experimental data possessing a wide range of Weber numbers. We demonstrate that our model can predict β (i.e., the maximum spreading diameter normalised in terms of initial droplet diameter) for various Newtonian liquids ranging from micro- to millimetre-sized droplets on different solid surfaces and can determine the transition between capillary and viscous regimes. Furthermore, theoretical relations for scaling laws observed by many researchers are derived.
在涉及喷雾冷却、燃烧等工业应用中，预测液滴撞击固体表面时的最大铺展直径，可以定量估计热去除和能量消耗。然而，尽管有许多关于液滴撞击行为的实验研究，但理论模型在预测最大铺展直径方面存在适用性限制。在本研究中，我们基于能量守恒原理，开发了一种考虑接触线水平和垂直方向粘附能的液滴撞击分析模型。该理论通过我们的实验和具有广泛韦伯数范围的现有实验数据得到验证。我们证明，我们的模型可以预测各种牛顿液体在不同固体表面上从微到毫米大小液滴的β（即初始液滴直径归一化的最大铺展直径），并可以确定从毛细到粘性的转变。此外，还推导出了许多研究人员观察到的标度律的理论关系。
