Dropwise Condensation on Hydrophobic Cylinders

TL;DR

This study investigates how the diameter of hydrophobic cylinders influences droplet growth during condensation, deriving a scaling law and confirming it with experiments, revealing a significant impact of cylinder size over temperature effects.

Contribution

The paper introduces a simple scaling law linking droplet growth to cylinder diameter and validates it through experiments, highlighting the dominant role of cylinder size in condensation.

Findings

Droplet growth decreases with increasing cylinder diameter.

The derived scaling law matches experimental trends.

Cylinder diameter impacts condensation more than surface temperature.

Abstract

In this work, we studied the effect of the diameter of horizontal hydrophobic cylinders on droplet growth. We postulate that the concentration gradient created by natural convection around a horizontal circular cylinder is related to the droplet growth on the cylinder by condensation. We derive a simple scaling law of droplet growth and compare it with experimental results. The predicted negative exponent of drop diameter (d) as a function of cylinder diameter (D) at different time points is similar to the general trend of experimental data. Further, this effect of cylinder diameter on droplet growth is observed to be stronger than the supersaturation conditions created by different surface temperatures.