Title: A computational study of air film evolution during droplet impact on a flat solid surface

Authors: Umesh; N.K. Singh

Addresses: Department of Mechanical Engineering, National Institute of Technology, Kurukshetra, India ' Department of Mechanical Engineering, National Institute of Technology, Kurukshetra, India

Abstract: The present study employs the volume of fluid (VOF) method to meticulously resolve the phenomenon of air trapping, capturing its evolution all the way into a spherical air bubble. The impact of velocity and droplet size on the air films progression is investigated; findings reveal that the micro bubble remains detached from the surface for lower impact velocity while it settles down on the surface for higher impact velocities. This outcome holds potential for practical applications requiring air bubble elimination by optimising the impact velocity. Furthermore, the presence of an air film impedes surface-to-droplet heat transfer. The solid surface experiences an increase in wall heat flux where the droplet contacts it, compared to air-solid contact regions due to waters superior thermal conductivity. Notably, maximum wall heat flux occurs at higher impact velocities, amplifying convection heat transfer.

Keywords: drop impact; two phase simulation; VOF method; air entrapment; impact velocity; droplet size.

DOI: 10.1504/PCFD.2024.140901

Progress in Computational Fluid Dynamics, An International Journal, 2024 Vol.24 No.5, pp.266 - 276

Received: 21 Jul 2023
Accepted: 20 Mar 2024
Published online: 03 Sep 2024 *

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