Dynamic behavior of non-evaporative droplet impact on a solid surface: Comparative study of R113, water, ethanol and acetone

摘要

Droplet impact on a solid surface is a common phenomenon observed in industries. Fundamental investigations of droplet impact are helpful in enhancing spray cooling capability and advance spray-wall impingement model. In this work, the effects of droplet diameter, impact velocity, viscosity, and surface tension on droplet impact dynamics were systematically investigated with four liquids, that is, R113, deionized water, ethanol, and acetone. Results illustrated that the initial droplet diameter minimally affects morphology and dynamic spreading factor, whereas large viscosity and surface tension hindered droplet spreading, thereby yielding a small maximum spreading factor and velocity. Low droplet viscosity and surface tension contribute to enhancing spray cooling capability by producing improved atomization, large spreading velocity, and extended contact area. The existing maximum spreading factor correlations failed to predict experimental results accurately. On the basis of experimental data in this work, general maximum spreading factor and splashing threshold correlations are proposed. All the proposed correlations agreed well with the present experimental results and literature data. The maximum spreading factor correlation indicated that large droplet impact velocity, small viscosity, and surface tension will produce a large maximum spreading capability.