https://doi.org/10.1140/epjs/s11734-023-00765-0
Regular Article
Growth dynamics of breath figures on phase change materials: a numerical study
1
Department of Mechanical Engineering, Birla Institute of Technology and Science Pilani, K. K. Birla Goa Campus, NH 17B Bypass Road, Zuarinagar, 403726, Sancoale, Goa, India
2
Department of Physics, Fergusson College (Autonomous), Fergusson College Road, 411004, Pune, Maharashtra, India
a
nileshp@goa.bits-pilani.ac.in
Received:
16
October
2022
Accepted:
9
January
2023
Published online:
19
January
2023
We present a numerical investigation of the effect of droplet motion on the growth dynamics of breath figures during condensation on phase change material. Breath figures are a micro-scale pattern of droplets that form when droplets condense on a cold surface. The numerical model considers the growth of droplets due to condensation, droplet coalescence, random droplet movement, and surface wettability. We study the dynamics of breath figures in terms of the time of evolution of the mean radius of droplets 
, surface coverage 
, and the droplet size distribution 
. We demonstrate that the droplets’ movement significantly changes the distribution of droplets condensing on a phase change material by increasing coalescence. We observed four growth regimes on phase change materials due to the movement of droplets. First, in the initial regime, 
, intermediate regime 
, coalescence-dominated regime 
, and late regime 
. The growth exponents are 
, 
, and 
. While the growth exponent 
depends on the contact angle of the surface 
. Furthermore, we show the scaling of the droplet size distributions at different times.
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