The role of surface wettability on the growth of vapour bubbles

P Sullivan and D Dockar and R Enright and MK Borg and R Pillai, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 217, 124657 (2023).

DOI: 10.1016/j.ijheatmasstransfer.2023.124657

The formation of heterogeneous vapour bubbles is widely studied due to its importance to two-phase thermal management systems, ultrasonic cleaning, and turbomachinery performance. However, the role that the surface plays in determining the growth of a bubble is still poorly understood. Currently, theoretical understanding of heterogeneous vapour bubble growth is limited to hemispherical bubbles or completely spherical bubbles next to a surface. We have previously developed an inertio-thermal model to accurately predict how heat transfer from the surrounding fluid affects homogeneous vapour bubble growth from the nanoscale to the macroscale (Sullivan et al. J. Fluid Mech. 948(A55):1-15, 2022). By accounting for the presence of the surface and its wettability on both the geometry of the bubble and on the available thermal energy in the surrounding fluid, we extend our model to capture heterogeneous vapour bubble growth. Using molecular simulations, we show not only how the strength of fluid-solid interaction affects the growth rate, but also how the formation of an adsorbed fluid layer under the bubble on lyophilic surfaces plays a vital role in determining the bubble shape and subsequent dynamics. These insights have potential to improve the performance of systems involving a change of phase from liquid to vapour by better understanding the role of surface wettability on this process.

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