Behavior of condensed droplets growth and jumping on superhydrophobic surface

¹ Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China
² School of Aeronautic Science and Engineering, Beihang University, Beijing, 100191, China

^* Corresponding author: wuxiaomin@mail.tsinghua.edu.cn

Abstract

Droplets on the superhydrophobic surface can fall off the surface spontaneously, which greatly promote dropwise condensation. This study considers a continuous droplet condensation process including droplet growth and droplet jumping. A droplet growth model considered NCG is developed and droplet jumping is simulated using VOF (Volume Of Fluid) model. Al–based superhydrophobic surfaces are prepared using chemical deposition and etching method. The Al-based superhydrophobic surface has a contact angle of 157°±1° and a rolling angle of 2°±1°. An observation experiment is designed to observe droplet jumping on superhydrophobic surface using a high– speed camera system. The result of droplet growth model shows a good match with experimental data in mid-term of droplet growth. Fordroplet jumping, simulation and experiment results show that droplet jumping of different diameter hasa universality in a non–dimensional form. The jumping process can be divided into 3 stages and droplet vibration is observed.