Instantaneous distribution of fluxes in the course of evaporation of sessile liquid droplets: Computer simulations

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Vol. 372; no. 1; pp. 127 - 134
• Main Authors: Semenov, S., Starov, V.M., Rubio, R.G., Velarde, M.G.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 03-12-2010; Elsevier
• Subjects: Chemistry; Droplets; Evaporation; Exact sciences and technology; Fluxes; General and physical chemistry; Heat transfer; Liquids; Mathematical analysis; Sessile droplets; Thermal conductivity; Vapour; Sessile droplets; Evaporation; Computer simulation; Support; Air; Droplet; Convection; Solid; Substrate; Liquid; Distribution; Thermal conductivity; Sessile; Calculation; Heat transfer
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2010.10.004

Universal rescaled dependence of the total vapour flux from the surface of a sessile droplet,
J, on contact angle
θ.
L
=
1
mm is the droplet base radius.
T
av
is the average temperature of the droplet surface.
J
π/2
is the total evaporation flux for
θ
=
π/2 in an isothermal system at temperature
T
av
.
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▶ The evaporation of sessile droplets has been investigated in a self consistent way. ▶ The influence of thermal conductivity of the solid support has been analyzed. ▶ The dependence of the total evaporation flux on the contact angle is universal.
Instantaneous distribution of mass and thermal fluxes inside and outside of an evaporating sessile droplet is considered using computer simulations. The latter distribution are calculated in a self consistent way by considering an interconnected problem of vapour transfer in the vapour phase outside the droplet, heat transfer in vapour, liquid and solid substrate, and Marangoni convection inside the liquid droplet. The influence of thermal conductivity of the solid support on the evaporation process is evaluated. It is shown that the lower the thermal conductivity of the solid substrate the higher is the deviation from the isothermal case. However, if the mean temperature of the droplet surface is used instead of the temperature of the surrounding air for the vapour concentration on the droplet surface then the calculated dependences coincide with those calculated for the isothermal case. The deduced dependences of instantaneous fluxes can be applied for self-consistent calculations of time evolution of the evaporation processes of sessile droplets.