We thank Dr. Yu for his discussion on two papers 1,2 of ours on thermal dispersion in porous media that appeared in the Journal of Heat Transfer. Dr. Yu rewrites our correlations established performing a series of numerical experiments as follows:

For the transverse dispersion:
$kdisyykf=0.022PeD1.71−ε1/4forPeD<10$
(26a)

$kdisyykf=0.0521−ε1/2 PeDforPeD>10$
(26b)
For the longitudinal dispersion:
$kdisxxkf=0.022PeD21−εforPeD<10$
(16a)

$kdisxxkf=2.7PeDε1/2forPeD>10$
(16b)
Dr. Yu assumes that the thermal dispersion decreases with the increase in the porosity, for it vanishes when...
1.
Kuwahara
,
F.
,
Nakayama
,
A.
, and
Koyama
,
H.
,
1996
, “
A Numerical Study of Thermal Dispersion in Porous Media
,”
ASME J. Heat Transfer
,
118
, pp.
756
761
.
2.
Kuwahara
,
F.
, and
Nakayama
,
A.
,
1999
, “
Numerical Determination of Thermal Dispersion Coefficients Using a Periodic Structure
,”
ASME J. Heat Transfer
,
121
, pp.
160
163
.
3.
Koch
,
D. L.
, and
,
J. F.
,
1985
, “
Dispersion in Fixed Beds
,”
J. Fluid Mech.
,
154
, pp.
399
427
.
4.
Kaviany, M., 1995, Principles of Heat Transfer in Porous Media, 2nd edition Springer-Verlag, New York, p. 209.