Inspired by the thermoregulation of mammals via perspiration, cooling strategies utilizing continuously fed evaporating droplets have long been investigated in the field, yet a comprehensive modeling capturing the detailed physics of the internal liquid flow is absent. In this study, an innovative computational model is reported, which solves the governing equations with temperature-dependent thermophysical properties in an iterative manner to handle mass and heat transfer coupling at the surface of a constant shape evaporating droplet. Using the model, evaporation from a spherical sessile droplet is simulated with and without thermocapillarity. An uncommon, nonmonotonic temperature variation on the droplet surface is captured in the absence of thermocapillarity. Although similar findings were reported in previous experiments, the temperature dip was attributed to a possible Marangoni flow. This study reveals that buoyancy-driven flow is solely responsible for the nonmonotonic temperature distribution at the surface of an evaporating steadily fed spherical water droplet.

References

1.
Smalyukh
,
I. I.
,
Zribi
,
O. V.
,
Butler
,
J. C.
,
Lavrentovich
,
O. D.
, and
Wong
,
G. C.
,
2006
, “
Structure and Dynamics of Liquid Crystalline Pattern Formation in Drying Droplets of DNA
,”
Phys. Rev. Lett.
,
96
(
17
), p.
177801
.
2.
Lim
,
T.
,
Jeong
,
J.
,
Chung
,
J.
, and
Chung
,
J. T.
,
2009
, “
Evaporation of Inkjet Printed Pico-Liter Droplet on Heated Substrates With Different Thermal Conductivity
,”
J. Mech. Sci. Technol.
,
23
(
7
), pp.
1788
1794
.
3.
Sefiane
,
K.
,
2010
, “
On the Formation of Regular Patterns From Drying Droplets and Their Potential Use for Bio-Medical Applications
,”
J. Bionic Eng.
,
7
(
S4
), pp.
S82
S93
.
4.
Ebrahimi
,
A.
,
Dak
,
P.
,
Salm
,
E.
,
Dash
,
S.
,
Garimella
,
S. V.
,
Bashir
,
R.
, and
Alam
,
M. A.
,
2013
, “
Nanotextured Superhydrophobic Electrodes Enable Detection of Attomolar-Scale DNA Concentration Within a Droplet by Non-Faradaic Impedance Spectroscopy
,”
Lab Chip
,
13
(
21
), pp.
4248
4256
.
5.
Kokalj
,
T.
,
Cho
,
H.
,
Jenko
,
M.
, and
Lee
,
L.
,
2010
, “
Biologically Inspired Porous Cooling Membrane Using Arrayed-Droplets Evaporation
,”
Appl. Phys. Lett.
,
96
(
16
), p.
163703
.
6.
Chakraborty
,
S.
,
Rosen
,
M. A.
, and
MacDonald
,
B. D.
,
2017
, “
Analysis and Feasibility of an Evaporative Cooling System With Diffusion-Based Sessile Droplet Evaporation for Cooling Microprocessors
,”
Appl. Therm. Eng.
,
125
, pp.
104
110
.
7.
Duh
,
J. C.
, and
Yang
,
W.-J.
,
1989
, “
Numerical Analysis of Natural Convection in Liquid Droplets by Phase Change
,”
Numer. Heat Transfer
,
16
(
2
), pp.
129
154
.
8.
Lozinski
,
D.
, and
Matalon
,
M.
,
1993
, “
Thermocapillary Motion in a Spinning Vaporizing Droplet
,”
Phys. Fluids A Fluid
,
5
(
7
), pp.
1596
1601
.
9.
Shih
,
A. T.
, and
Megaridis
,
C. M.
,
1996
, “
Thermocapillary Flow Effects on Convective Droplet Evaporation
,”
Int. J. Heat Mass Tran.
,
39
(
2
), pp.
247
257
.
10.
Ruiz
,
O. E.
, and
Black
,
W. Z.
,
2002
, “
Evaporation of Water Droplets Placed on a Heated Horizontal Surface
,”
ASME J. Heat Transf.
,
124
(5), pp. 854–863.
11.
Bouchenna
,
C.
,
Saada
,
M. A.
,
Chikh
,
S.
, and
Tadrist
,
L.
,
2017
, “
Generalized Formulation for Evaporation Rate and Flow Pattern Prediction Inside an Evaporating Pinned Sessile Drop
,”
Int. J. Heat Mass Tran.
,
109
, pp.
482
500
.
12.
Girard
,
F.
,
Antoni
,
M.
,
Faure
,
S.
, and
Steinchen
,
A.
,
2006
, “
Evaporation and Marangoni Driven Convection in Small Heated Water Droplets
,”
Langmuir
,
22
(
26
), pp.
11085
11091
.
13.
Hu
,
H.
, and
Larson
,
R. G.
,
2005
, “
Analysis of the Effects of Marangoni Stresses on the Microflow in an Evaporating Sessile Droplet
,”
Langmuir
,
21
(
9
), pp.
3972
3980
.
14.
Ristenpart
,
W.
,
Kim
,
P.
,
Domingues
,
C.
,
Wan
,
J.
, and
Stone
,
H.
,
2007
, “
Influence of Substrate Conductivity on Circulation Reversal in Evaporating Drops
,”
Phys. Rev. Lett.
,
99
(
23
), p.
234502
.
15.
Xu
,
X.
,
Luo
,
J.
, and
Guo
,
D.
,
2009
, “
Criterion for Reversal of Thermal Marangoni Flow in Drying Drops
,”
Langmuir
,
26
(
3
), pp.
1918
1922
.
16.
Zhang
,
K.
,
Ma
,
L.
,
Xu
,
X.
,
Luo
,
J.
, and
Guo
,
D.
,
2014
, “
Temperature Distribution Along the Surface of Evaporating Droplets
,”
Phys. Rev. E
,
89
(
3
), p.
032404
.
17.
Barash
,
L. Y.
,
2015
, “
Dependence of Fluid Flows in an Evaporating Sessile Droplet on the Characteristics of the Substrate
,”
Int. J. Heat Mass Tran.
,
84
, pp.
419
426
.
18.
Hu
,
H.
, and
Larson
,
R. G.
,
2002
, “
Evaporation of a Sessile Droplet on a Substrate
,”
J. Phys. Chem. B
,
106
(
6
), pp.
1334
1344
.
19.
Deegan
,
R. D.
,
Bakajin
,
O.
,
Dupont
,
T. F.
,
Huber
,
G.
,
Nagel
,
S. R.
, and
Witten
,
T. A.
,
1997
, “
Capillary Flow as the Cause of Ring Stains From Dried Liquid Drops
,”
Nat.
,
389
(
6653
), pp.
827
829
.
20.
Deegan
,
R. D.
,
Bakajin
,
O.
,
Dupont
,
T. F.
,
Huber
,
G.
,
Nagel
,
S. R.
, and
Witten
,
T. A.
,
2000
, “
Contact Line Deposits in an Evaporating Drop
,”
Phys. Rev. E
,
62
(
1 Pt B
), p.
756
.
21.
Girard
,
F.
,
Antoni
,
M.
, and
Sefiane
,
K.
,
2008
, “
On the Effect of Marangoni Flow on Evaporation Rates of Heated Water Drops
,”
Langmuir
,
24
(
17
), pp.
9207
9210
.
22.
Kaneda
,
M.
,
Hyakuta
,
K.
,
Takao
,
Y.
,
Ishizuka
,
H.
, and
Fukai
,
J.
,
2008
, “
Internal Flow in Polymer Solution Droplets Deposited on a Lyophobic Surface During a Receding Process
,”
Langmuir
,
24
(
16
), pp.
9102
9109
.
23.
Karapetsas
,
G.
,
Matar
,
O. K.
,
Valluri
,
P.
, and
Sefiane
,
K.
,
2012
, “
Convective Rolls and Hydrothermal Waves in Evaporating Sessile Drops
,”
Langmuir
,
28
(
31
), pp.
11433
11439
.
24.
Strotos
,
G.
,
Gavaises
,
M.
,
Theodorakakos
,
A.
, and
Bergeles
,
G.
,
2008
, “
Numerical Investigation on the Evaporation of Droplets Depositing on Heated Surfaces at Low Weber Numbers
,”
Int. J. Heat Mass Tran.
,
51
(
7–8
), pp.
1516
1529
.
25.
Ait Saada
,
M.
,
Chikh
,
S.
, and
Tadrist
,
L.
,
2010
, “
Numerical Investigation of Heat and Mass Transfer of an Evaporating Sessile Drop on a Horizontal Surface
,”
Phys. Fluids
,
22
(
11
), p.
112115
.
26.
Carle
,
F.
,
Sobac
,
B.
, and
Brutin
,
D.
,
2013
, “
Experimental Evidence of the Atmospheric Convective Transport Contribution to Sessile Droplet Evaporation
,”
Appl. Phys. Lett.
,
102
(
6
), p.
061603
.
27.
Yoshitake
,
Y.
,
Yasumatsu
,
S.
,
Kaneda
,
M.
,
Nakaso
,
K.
, and
Fukai
,
J.
,
2009
, “
Structure of Circulation Flows in Polymer Solution Droplets Receding on Flat Surfaces
,”
Langmuir
,
26
(
6
), pp.
3923
3928
.
28.
Churchill
,
S. W.
,
2002
, “
Free Convection Around Immersed Bodies
,”
Heat Exchanger Design Handbook
,
G. F.
Hewitt
, ed.,
Begell House
,
New York
.
29.
Akkuş
,
Y.
,
Çetin
,
B.
, and
Dursunkaya
,
Z.
,
2017
, “
Modeling of Evaporation From a Sessile Constant Shape Droplet
,”
ASME
Paper No. ICNMM2017-5537
.
30.
Mahmud
,
M. A.
, and
MacDonald
,
B. D.
,
2017
, “
Experimental Investigation of Interfacial Energy Transport in an Evaporating Sessile Droplet for Evaporative Cooling Applications
,”
Phys. Rev. E
,
95
(1), p. 012609.
31.
Robinson
,
P. J.
, and
Davies
,
J. A.
,
1972
, “
Laboratory Determinations of Water Surface Emissivity
,”
J. Appl. Metrol.
,
11
(
8
), pp.
1391
1393
.
32.
Mollaret
,
R.
,
Sefiane
,
K.
,
Christy
,
J.
, and
Veyret
,
D.
,
2004
, “
Experimental and Numerical Investigation of the Evaporation Into Air of a Drop on a Heated Surface
,”
Chem. Eng. Res. Des.
,
82
(
4
), pp.
471
480
.
33.
Incropera
,
F. P.
, and
DeWitt
,
D. P.
,
1990
,
Fundamentals of Heat and Mass Transfer
,
Wiley
,
New York
.
34.
Vargaftik
,
N.
,
Volkov
,
B.
, and
Voljak
,
L.
,
1983
, “
International Tables of the Surface Tension of Water
,”
J. Phys. Chem. Ref. Data
,
12
(
3
), pp.
817
820
.
35.
Carey
,
V. P.
,
1992
,
Liquid-Vapor Phase Change Phenomena
,
Hemisphere Publishing House
,
New York
.
36.
Ward
,
C.
, and
Duan
,
F.
,
2004
, “
Turbulent Transition of Thermocapillary Flow Induced by Water Evaporation
,”
Phys. Rev. E
,
69
(
5 Pt. 2
), p.
056308
.
37.
Xu
,
X.
, and
Luo
,
J.
,
2007
, “
Marangoni Flow in an Evaporating Water Droplet
,”
Appl. Phys. Lett.
,
91
(
12
), p.
124102
.
38.
Savino
,
R.
,
Paterna
,
D.
, and
Lappa
,
M.
,
2003
, “
Marangoni Flotation of Liquid Droplets
,”
J. Fluid Mech.
,
479
, pp.
307
326
.
39.
Duan
,
F.
, and
Ward
,
C.
,
2005
, “
Surface Excess Properties From Energy Transport Measurements During Water Evaporation
,”
Phys. Rev. E
,
72
(
5
), p.
056302
.
40.
Duan
,
F.
,
Badam
,
V.
,
Durst
,
F.
, and
Ward
,
C.
,
2005
, “
Thermocapillary Transport of Energy During Water Evaporation
,”
Phys. Rev. E
,
72
(
5
), p.
056303
.
41.
Ghasemi
,
H.
, and
Ward
,
C.
,
2010
, “
Energy Transport by Thermocapillary Convection During Sessile-Water-Droplet Evaporation
,”
Phys. Rev. Lett.
,
105
(
13
), p.
136102
.
You do not currently have access to this content.