In this paper a theoretical investigation is reported on the effect of surface roughness on the phenomenon of Leidenfrost-levitation of droplets above a hot surface. The problem is solved first approximately using a macroscopic approach in which the roughness is replaced by a semi-empirical slip condition of the Beavers-Joseph type. Next, a microscopic model which determines the vapor flow in the close vicinity of the rough surface is solved numerically. Three basic periodic roughnesses are examined: triangular, rectangular and semi-cylindrical. The effect of the relative size of the droplet and the roughness elements on the vapor flow is investigated in the course of the study.

1.
Avedisian
C. T.
, and
Koplik
J.
,
1987
, “
Leidenfrost Boiling of Methanol Droplets on Hot Porous/Ceramic Surfaces
,”
Int. J. Heat and Mass Transfer
, Vol.
30
, pp.
379
393
.
2.
Baumeister
K. J.
, and
Simon
F. F.
,
1973
, “
Leidenfrost Temperature—its Correlation for Liquid Metals, Cryogens, Hydrocarbons and Water
,”
ASME Journal of Heat Transfer
, Vol.
95
, pp.
166
173
.
3.
Beavers
G. S.
, and
Joseph
D. D.
,
1967
, “
Boundary Conditions at a Naturally Permeable Wall
,”
Journal of Fluid Mechanics
, Vol.
30
, pp.
197
207
.
4.
Bell
K. J.
,
1967
, “
The Leidenfrost Phenomenon: A Survey
,”
Chemical Engineering Progress Symposium Series
, Vol.
63
, pp.
73
82
.
5.
Chandra
S.
, and
Avedisian
C. T.
,
1991
, “
On the Collision of a Droplet With a Solid Surface
,”
Proceedings of the Royal Society of London A
, Vol.
432
, pp.
13
41
.
6.
Chandra
S.
, and
Avedisian
C. T.
,
1992
, “
Observations of Droplet Impingement on a Ceramic Porous Surface
,”
International Journal of Heat and Mass Transfer
, Vol.
35
, pp.
2377
2388
.
7.
Fatehi
M.
, and
Kaviany
M.
,
1990
, “
Analysis of Levitation of Saturated Liquid Droplets on Permeable Surfaces
,”
International Journal of Heat and Mass Transfer
, Vol.
33
, pp.
983
944
.
8.
Gotfried
B. S.
,
Lee
C. J.
, and
Bell
K. J.
,
1966
, “
The Leidenfrost Phenomenon: Film Boiling of Liquid Droplets on a Flat Plate
,”
International Journal of Heat and Mass Transfer
, Vol.
9
, pp.
1167
1187
.
This content is only available via PDF.
You do not currently have access to this content.