Simulation of asymmetric evaporation of inclined droplets considering natural convection

• Published in: Chemical engineering science Vol. 278; p. 118890
• Main Authors: Chen, Facheng, Cai, Jiejin, Chamakos, Nikolaos T., Papathanasiou, Athanasios G., Gong, Ziqi, Li, Qiong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.08.2023
• Subjects: Contact angle hysteresis; Contact line; Inclination angle; Marangoni flow; Contact angle hysteresis; Inclination angle; Marangoni flow; Contact line
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2023.118890

•A droplet evaporation model based on liquid–solid interaction is proposed.•Droplet morphology, asymmetric contact angle are accurately captured.•Effect of natural convection at different inclination angles is studied.•Relative magnitudes of droplet evaporation rates and pinning time are explored. A liquid–solid interaction-based mesh model is used to analyze droplet evaporation on tilted surfaces. The model accounts for droplet morphology, contact angle hysteresis, evaporative cooling, vapor diffusion, and natural convection. Comparison with experiments validates the model's accuracy. Tilt angle affects Marangoni flow within the droplet, leading to abrupt changes in heat and evaporation fluxes. During evaporation, the asymmetric physical field becomes symmetrical as the contact line moves, with temperature minimum and Marangoni flow stagnation point returning to the center of the droplet. The natural convection direction is guided by the angle of inclination, causing higher evaporation flux on the windward side. Evaporation rate is influenced by the angle of inclination; obtuse angle (i.e. with α=135°) reduce evaporation rates by 8.4% compared to acute angle (i.e. with α=45°). Adjusting inclination can control natural convection direction and droplet evaporation pattern, thus influencing the evaporation rate.