Transient Effects in Evaporating Sessile Drops: With and Without Heating

[+] Author and Article Information
Liu Bin

Tianjin Key Lab of Refrigeration Technology,
Tianjin University of Commerce,
Tianjin 300134, China

Rachid Bennacer

Paris Saclay,
61 Avenue du Président Wilson,
Cachan 94235, France;
Tianjin Key Lab of Refrigeration Technology,
Tianjin University of Commerce,
Tianjin 300134, China
e-mail: rachid.bennacer@ens-cachan.fr

Khellil Sefiane

School of Engineering,
University of Edinburgh,
Kings Buildings Mayfield Road,
Edinburgh EH9 3JL, UK;
Tianjin Key Lab of Refrigeration Technology,
11 Tianjin University of Commerce,
12 Tianjin 300134, China

Annie Steinchen

Bd Escadrille Normandie Niemen,
Marseille 13397, France

1Corresponding author.

Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF HEAT TRANSFER. Manuscript received October 19, 2014; final manuscript received March 27, 2015; published online June 1, 2016. Assoc. Editor: Ziad Saghir.

J. Heat Transfer 138(9), 091009 (Jun 01, 2016) (6 pages) Paper No: HT-14-1690; doi: 10.1115/1.4032954 History: Received October 19, 2014; Revised March 27, 2015

The evaporation phenomenon of sessile drops has been recently subject to an extensive interest by industry and researchers. This is stimulated by new developments in exploiting this basic process for more industrial technologies and biological applications. The underlying mechanisms to this apparently simple, yet elusive phenomenon as well as its complete description are still far from being achieved. Many theoretical models describe the phenomenon by neglecting some important physical aspects of the problem. Transient thermal effects can indeed be very crucial, nonetheless very often neglected. In a recent work, a new approach was adopted to model the physical process taking into account the thermal resistance of the substrate. This was, however, limited to the investigation of cases where steady-state assumption is adopted. In such pseudo steady-state, a controlling nondimensional SB number was identified. The evaporation of sessile drops deposited on a substrate is found to exhibit various regimes. These latter are related to the wetting and spreading behavior of the drop, depending on whether the drop is pinned with a decreasing contact angle, with a receding contact line and constant angle or a mixed behavior. Most modeling attempts have considered vapor diffusion in the gas phase as the limiting mechanism for evaporation. However, the heat and mass transfer in the solid, liquid, and gas phases describe the problem and predict droplets evaporation. It is worth noting that most theoretical and numerical models proposed so far assume the quasi steady-state hypothesis and neglect transient effects. It is essential to acknowledge that not only the three phases (gas, solid, and liquid) take part in mass and energy transport but also the interfaces between these phases are equally important. The liquid–vapor interface, for instance is the surface through which phase change takes place. This interface is subjected to evaporative cooling effects, depending on the physical dimensions, properties as well as experimental conditions. In the present paper, we propose to extend this approach to account for transient effects. The results of this investigation demonstrate that in some cases transient effects can extend beyond the lifetime of the drop, making the entire process transitory. These effects are quantified and the implications for modeling wetting drops are discussed.

Copyright © 2016 by ASME
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Fig. 1

Illustrating drawing of the energy balance and thermal resistances

Grahic Jump Location
Fig. 5

Temperature change versus time for different liquids (e = 1 mm)

Grahic Jump Location
Fig. 4

The transitory time as a function of substrate thickness for a 1 mm methanol droplet

Grahic Jump Location
Fig. 3

Normalized simulation results and analytical trends

Grahic Jump Location
Fig. 2

Temperature change versus time for methanol drop at various substrate thicknesses and the gas thermal effect

Grahic Jump Location
Fig. 6

Temperature change versus time for different liquids resistance decrease




Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In