Impingement of droplets with various liquid viscosities on a low-speed rotational surface

IF 2.8 2区工程技术 Q2 ENGINEERING, MECHANICAL

Experimental Thermal and Fluid Science Pub Date : 2025-01-30 DOI:10.1016/j.expthermflusci.2025.111426

Wei Jia , Yueyao Zheng , Xiaoyu Cai

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引用次数: 0

Abstract

The dynamic behavior of droplets with different liquid viscosities impacting a low-speed rotational surface was experimentally investigated. The effects of rotation and viscosity on the droplet morphology and spreading behavior were analyzed. The experimental results show that five typical morphologies-cap, splitting, deposition, secondary droplets, and lobes-exist in the droplet spreading on a rotational surface. The Rossby number and Ohnesorge number have important effects on the droplet morphologies. At a high Rossby number (Ro > 4), the droplet exhibits a cap shape at the end of the retraction stage because the inertial force plays a dominant role. At a low Rossby number (Ro < 2), the droplet exhibits splitting or deposition on the rotational surface. Secondary droplets may appear under certain conditions for the droplets with medium or high viscosity owing to the interaction among the tangential force, viscous force, and surface tension. At a medium Rossby number, the droplet is mainly deposited or cap-shaped in the end. The phenomenon of lobes is independent of the Rossby number, but is related to the Ohnesorge number. The lobes appear only at a medium or low Ohnesorge number during droplet spreading and retraction. In addition, the spreading behavior of a droplet impacting a rotational surface can be divided into retraction mode, oscillatory equilibrium mode, and continuous spreading mode. Empirical models were proposed for the maximum circumferential wetting length and the maximum wetting time. For the retraction mode, the empirical models produce mean relative errors of 5.08 % and 7.76 % for the maximum circumferential wetting length and the maximum wetting time, respectively. For the oscillatory equilibrium mode, the empirical models produce mean relative errors of 4.79 % and 9.98 % for the maximum circumferential wetting length and the maximum wetting time, respectively. The agreement between the predicted and experimental results is improved significantly when both rotation and viscosity effects are considered.

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来源期刊

Experimental Thermal and Fluid Science 工程技术-工程：机械

CiteScore

6.70

自引率

3.10%

发文量

159

审稿时长

34 days

期刊介绍： Experimental Thermal and Fluid Science provides a forum for research emphasizing experimental work that enhances fundamental understanding of heat transfer, thermodynamics, and fluid mechanics. In addition to the principal areas of research, the journal covers research results in related fields, including combined heat and mass transfer, flows with phase transition, micro- and nano-scale systems, multiphase flow, combustion, radiative transfer, porous media, cryogenics, turbulence, and novel experimental techniques.