Abstract
Six different surfaces ranging from superhydrophilic to superhydrophobic were fabricated. Droplet impact experiments were conducted on these surfaces with water droplets 2.25 mm in diameter at a Weber number close to zero to study the effects of surface wettability on the impact process and post-impact oscillation. Droplet impact on all surfaces, except for superhydrophobic surfaces, is dominated by a spreading stage and no evident retraction is observed. Using the inertia-capillarity time tc = ρR03/σ as characteristic time, the spreading stage on all surfaces at We < 0.5 was calculated to be 2.25 ± 0.11tc; further, it could be divided into inertial and viscous spreading stages at 1 ± 0.11tc based on droplet height evolution. A semi-empirical correlation for calculating the evolution of spreading factors on different surfaces was fitted by a piecewise exponential function using experimental data, and a deviation of ±20% was observed between the fitted and experimental data.
Original language | English |
---|---|
Pages (from-to) | 495-503 |
Number of pages | 9 |
Journal | Chemical Engineering Science |
Volume | 207 |
DOIs | |
Publication status | Published - 2 Nov 2019 |
Externally published | Yes |
Keywords
- Advancing contact angle
- Droplet spreading
- Low Weber number
- Surface wettability