Modelling spontaneous droplet transport in deformable divergent channels

Dongsheng Chen; Haiyi Zhong; Zhongzheng Wang; Si Suo; Deheng Wei; Yixiang Gan*

Authors

Dongsheng Chen School of Civil Engineering, The University of Sydney, NSW 2006, Australia
Haiyi Zhong School of Civil Engineering, The University of Sydney, NSW 2006, Australia
Zhongzheng Wang School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, QLD 4001, Australia
Si Suo Department of Civil and Environmental Engineering, Imperial Collage London, London, SW7 2AZ, United Kingdom
Deheng Wei School of Civil Engineering, The University of Sydney, NSW 2006, Australia；State Key Laboratory of Intelligent Deep Metal Mining and Equipment, School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, P. R. China
Yixiang Gan* School of Civil Engineering, The University of Sydney, NSW 2006, Australia (Email: yixiang.gan@sydney.edu.au)

Abstract

Spontaneous droplet movement has gained increased interest in many applications, including microfluidics and microfabrication. This study focuses on the numerical investigation of driving mechanisms of spontaneous droplet motion. The numerical model using the phasefield method was validated by available experimental data. In this study, a heterogeneous wettability condition is implemented to reproduce contact angle hysteresis for the accurate prediction of spontaneous droplet dynamics. Through analysing the capillary pressure within the droplet, the driving mechanism is identified as being governed by the pressure difference between the two interfaces which depends on channel configuration, wettability, and contact angle hysteresis. The impact of channel deformability was further studied, revealing that channel deformability leads to significant changes in velocity or even reversed droplet movement direction. This study provides a novel numerical framework for controllable spontaneous droplet movement in flexible channels.

Document Type: Original article

Cited as: Chen, D., Zhong, H., Wang, Z., Suo, S., Wei, D., Gan, Y. Modelling spontaneous droplet transport in deformable divergent channels. Capillarity, 2025, 15(1): 4-11. https://doi.org/10.46690/capi.2025.04.02

Keywords:

Spontaneous droplet transport, moving contact line, fluid-solid interaction, contact angle hysteresis.

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Modelling spontaneous droplet transport in deformable divergent channels

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