Results are reported for an experimental and numerical study of forced and mixed convective heat transfer in a liquid-saturated horizontal porous duct. The cross section of the duct has a sudden expansion with a heated region on the lower surface downstream and adjacent to the expansion. Within the framework of Darcy’s formulation, the calculated and measured Nusselt numbers for 0.1 < Pe < 100 and 50 < Ra < 500 are in excellent agreement. Further, the calculated Nusselt numbers are very close to those for the bottom-heated flat duct. This finding has important implications for convective heat and mass transfer in geophysical systems and porous matrix heat exchangers. The calculations were also carried out for glass bead-packed beds saturated with water using non-Darcy’s formula. The streamlines in the forced convection indicate that, even with non-Darcy effects included, recirculation is not observed downstream of an expansion and the heat transfer rate is decreased but only marginally.

1.
Abu-Hijleh
B.
,
1997
, “
Convection Heat Transfer from a Laminar Flow over a 2-D Backward Facing Step with Asymmetric and Orthotropic Floor Segments
,”
Numerical Heat Transfer, Part A: Applications
, Vol.
31
, pp.
325
335
.
2.
Cheng
P.
,
1977
a, “
Combined Free and Forced Convection Flow about Inclined Surfaces in Porous Media
,”
Int. J. Heat Mass Transfer
, Vol.
20
, pp.
807
814
.
3.
Cheng
P.
,
1977
b, “
Similarity Solutions for Mixed Convection from Horizontal Impermeable Surfaces in Saturated Porous Media
,”
Int. J. Heat Mass Transfer
, Vol.
20
, pp.
893
898
.
4.
Cheng, P., Hsu, C. T., and Chowdhury, A., “Forced Convection in the Entrance Region of a Packed Channel With Asymmetric Heating,” ASME Journal of Heat Transfer, pp. 946–954.
5.
Cheng
P.
, and
Vortmeyer
D.
,
1988
, “
Transverse Thermal Dispersion and Wall Channeling in a Packed Bed with Forced Convective Flow
,”
Chemical Eng. Sci.
, Vol.
43
, pp.
2523
2532
.
6.
Choi
C. Y.
, and
Kulacki
F. A.
,
1992
, “
Mixed Convection Through Vertical Porous Annuli Locally Heated From the Inner Cylinder
,”
ASME JOURNAL OF HEAT TRANSFER
, Vol.
114
, pp.
143
151
.
7.
Clarksean, R., Kwendakwema, N., and Boehm, R., 1988, “A Study of Mixed Convection in Porous Medium Between Vertical Concentric Cylinders,” Proceedings of the 1988 National Heat Transfer Conference, Vol. 2, ASME, New York, pp. 339–344.
8.
Elder
J. W.
,
1967
, “
Steady Free Convection in a Porous Medium Heated from Below
,”
J. Fluid Mech.
, Vol.
27
, pp.
29
48
.
9.
Gooray, A. M., Watkins, C. B., and Aung, W., 1981, “Numerical Calculations of Turbulent Heat Transfer Downstream of a Rearward-Facing Step,” Proceedings of the 2nd International Conference on Numerical Method in Laminar and Turbulent Flow, Venice, Italy, John Wiley and Sons, New York, pp. 639–651.
10.
Gosman, A. D., Pun, W. M., Runchal, A. K., Spalding, D. B., and Wolfshtein, M., 1969, Heat and Mass Transfer in Recirculating Flows, Academic Press, New York.
11.
Homsy
G. M.
, and
Sherwood
A. E.
,
1976
, “
Convective Instabilities in Porous Media with Through Flow
,”
AlChE J.
, Vol.
22
, pp.
168
174
.
12.
Kladias
N.
, and
Prasad
V.
,
1991
, “
Experimental Verification of Darcy-Brinkman-Forchheimer Flow Model for Natural Convection in Porous Media
,”
J. Thermophysics and Heat Transfer
, Vol.
5
, pp.
560
576
.
13.
Lai
F.-C.
, and
Kulacki
F. A.
,
1988
, “
Aiding and Opposing Mixed Convection in a Vertical Layer with a Finite Wall Heat Source
,”
Int. J. Heat Mass Transfer
, Vol.
31
, pp.
1049
1061
.
14.
Lai
F. C.
, and
Kulacki
F. A.
,
1991
, “
Experimental Study of Free and Mixed Convection in Horizontal Porous Layers Heated From Below
,”
Int. J. Heat Mass Transfer
, Vol.
34
, pp.
525
541
.
15.
Nield
D. A.
,
1991
, “
The Limitation of the Brinkman-Forchheimer Equation in Modeling Flow in a Saturated Porous Medium and at an Interface
,”
Int. J. Heat Fluid Flow
, Vol.
12
, pp.
269
272
.
16.
Patankar, S. V., 1980, Numerical Heat Transfer and Fluid Flow, Hemisphere/ McGraw-Hill, New York.
17.
Prasad
V.
,
Lai
F. C.
, and
Kulacki
F. A.
,
1988
, “
Mixed Convection in Horizontal Porous Layers Heated From Below
,”
ASME JOURNAL OF HEAT TRANSFER
, Vol.
110
, pp.
395
402
.
18.
Prats
M.
,
1966
, “
The Effect of Horizontal Fluid Flow on Thermally Induced Convection Currents in Porous Mediums
,”
J. Geophysical Research
, Vol.
71
, pp.
4835
4837
.
19.
Reda
D. C.
,
1988
, “
Mixed Convection in a Liquid-Saturated Porous Medium
,”
ASME JOURNAL OF HEAT TRANSFER
, Vol.
110
, pp.
147
154
.
20.
Roache, P. J., 1976, Computational Fluid Dynamics, Hermosa Publishers, Albuquerque, NM.
21.
Sinha
S. N.
,
Gupta
A. K.
, and
Oberai
M. M.
,
1981
, “
Laminar Separating Flow over Backsteps and Cavities—Part II: Cavities
,”
AIAA J.
, Vol.
20
, pp.
370
375
.
22.
Sutton
F. M.
,
1970
, “
The Onset of Convection in a Porous Channel with Net Through Flow
,”
Physics of Fluids
, Vol.
13
, pp.
1931
1934
.
23.
Vafai
K.
,
1984
, “
Convective Flow and Heat Transfer in Variable-Porosity Media
,”
J. Fluid Mech.
, Vol.
147
, pp.
233
259
.
24.
Vafai
K.
, and
Huang
P. C.
,
1994
, “
Analysis of Heat Transfer Regulation and Modification Employing Intermittently Emplaced Porous Cavities
,”
ASME JOURNAL OF HEAT TRANSFER
, Vol.
116
, pp.
604
613
.
25.
Wooding
R. A.
,
1963
, “
Convection in a Saturated Porous Medium at Large Rayleigh or Peclet number
,”
J. Fluid Mech.
, Vol.
15
, pp.
527
544
.
26.
Yamamoto
H.
,
Seki
N.
, and
Fukusako
S.
,
1979
, “
Forced Convection Heat Transfer on Heated Bottom Surface of Cavity
,”
ASME JOURNAL OF HEAT TRANSFER
, Vol.
101
, pp.
475
479
.
27.
Yokoyama, Y., 1993, Convective Heat Transfer in Porous Medium Downstream of a Sudden Expansion, Doctoral dissertation, Colorado State University, Fort Collins, CO.
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