Analysis of the effect of surface slope changes on the growth, motion, and coalescence of droplets in dropwise condensation

Authors

1 Iran University of Science and Technology, Tehran, Iran.

2 Mech. Eng., Iran University of Science and Technology, Tehran, Iran

3 Associate Professor Head of LNG Research Laboratory School of Mechanical Engineering, Iran University of Science and Technology, 16846, Tehran, Iran.

Abstract

Droplet coalescence or adhesion occurs when water droplets attach to a bond and form a single drop. In this paper, using numerical simulations, the dynamic behavior of merging two drops of equal and unequal size on a inclined surface is studied. The effect of surface slope and droplet diameter on the behavioral dynamics of the liquid bridge and the three-phase droplet contact line is integrated. During the solution, we constantly see the dominance of gravity and surface tension forces over the fluid flow. The results show that in the integration of small droplets, more intense oscillations occur in the area of the liquid bridge and the displacement of the three-phase line, compared to the larger droplets. In small droplets, with increasing slope level, the fluctuations in the displacement of the beginning and end points of the three-phase line become severe, which weakens the high-frequency oscillations in the liquid bridge area. For merging large droplets, the forward and rear end displacements of the droplet increase uniformly. The results of merging unequal droplets show that the speed of liquid bridge formation in this case is higher than the merger of symmetric droplets, which leads to more oscillations with low oscillation amplitude and high oscillation frequency.

Keywords

References

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Journal of Solid and Fluid Mechanics
Volume 12, Issue 6
January and February 2023
Pages 163-180

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