A spherical dielectric droplet translating steadily in another dielectric liquid with a uniform electric field imposed in the translational direction of the droplet is studied theoretically. With the small Reynolds number and large Peclet number assumptions, analytic solutions are obtained for the stream function with a term involving the interfacial temperature distribution which is then computed numerically. The results indicate that the interfacial temperature distribution is indeed nonuniform and the thermocapillarity might exist thereby. The induced thermocapillary flows in the droplet are usually of multiple cells with which the heat transfer rate may increases or decreases depending on whether the original flow is enhanced or suppressed. For the example calculated in the present study, the heat transfer rate is decreased by the thermocapillary effect.

Issue Section:
Micro-Scale Heat Transfer
Keywords:
Heat Transfer
Topics:
Drops, Electric fields, Flow (Dynamics), Heat transfer, Transients (Dynamics), Temperature distribution, Dielectric liquids, Reynolds number
1.
Abramzon
B.
, and
Borde
I.
,
1980
, “
Conjugate Unsteady Heat Transfer from a Droplet in Creeping Flow
,”
AIChE J.
, Vol.
26
, No.
4
, pp.
536
–
544
.
2.
Chang
L. S.
, and
Berg
J. C.
,
1985
, “
The Effect of Interfacial Tension Gradients on the Flow Structure of Single Drops or Bubbles Translating in an Electric Field
,”
AIChE J.
, Vol.
31
, No.
4
, pp.
551
–
557
.
3.
Chang
L. S.
,
Charleson
T. E.
, and
Berg
J. C.
,
1982
, “
Heat and Mass Transfer to a Translating Drop in an Electric Field
,”
Int. J. Heat Mass Transfer
, Vol.
25
, pp.
1023
–
1030
.
4.
Chung
J. N.
, and
Oliver
D. L. R.
,
1990
, “
Transient Heat Transfer in a Fluid Sphere Translating in an Electric Field
,”
ASME JOURNAL OF HEAT TRANSFER
, Vol.
112
, pp.
84
–
91
.
5.
Happel, J., and Brenner, H., 1965, Low Reynolds Number Hydrodynamics, Prentice-Hall, Englewood Cliffs, NJ.
6.
Johns
L. E.
, and
Beckmann
R. B.
,
1966
, “
Mechanisms of Dispersed-Phase Mass Transfer in Viscous, Single-Drop Extraction Systems
,”
AIChE J.
, Vol.
12
, pp.
10
–
16
.
7.
Morrison
F. A.
,
1977
, “
Transient Heat and Mass Transfer to a Drop in an Electric Field
,”
ASME JOURNAL OF HEAT TRANSFER
, Vol.
99
, pp.
269
–
273
.
8.
Patankar, S. V., 1980, Numerical Heat Transfer and Fluid Flow, Hemisphere, Washington, DC.
9.
Tang, W. L., 1994, “Thermocapillary Effects on Transient Heat Transfer in a Droplet Translating in an Electric Field,” M. S. thesis, Department of Mechanical Engineering, National Taiwan University, R.O.C.
10.
Taylor
G. I.
,
1966
, “
Studies in Electrohydrodynamics, I. The Circulation Produced in a Drop by an Electric Field
,”
Proc. Roy. Soc., Lond.
, Vol.
291A
, pp.
159
–
166
.
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