TY - JOUR
TI - Measurement of the coefficient of transverse dispersion in flow through packed beds for a wide range of values of the schmidt number
T2 - TRANSPORT IN POROUS MEDIA
VL - 44
IS - 1
SN - 0169-3913
SP - 165-180
PY - 2001
DO - 10.1023/A:1010769402206
AU - Quesado Delgado, J.
AU - Carvalho, J.
AB - Experimental values of the coefficient of transverse dispersion (DT) were measured with
the system 2-naphthol/water, over a range of temperatures between 293 K and 373 K, which corresponds
to a range of values of viscosity (µ) between 2.83 × 10¿4 Ns/m2 and 1.01 × 10¿3 Ns/m2
and of molecular diffusion coefficient (Dm) between 1.03×10¿9 m2/s and 5.49×10¿9 m2/s. Since
the density (¿) of water is close to 103 kg/m3, the corresponding variation of the Schmidt number
(Sc= µ/¿Dm) was in the range 1000 ¿ 50. More than 200 experimental values of the transverse
dispersion coefficient were obtained using beds of silica sand with average particle sizes (d) of
0.297 and 0.496 mm, operated over a range of interstitial liquid velocities (u) between 0.1 mm/s
and 14 mm/s and this gave a variation of the Reynolds number (Re= ¿du¿/µ) between 0.01 and 3.5.
Plots of the dimensionless coefficient of transverse dispersion (DT/Dm) vs. the Peclet number
(Pem = ud/Dm) based on molecular diffusion bring into evidence the influence of Sc on transverse
dispersion. As the temperature is increased, the value of Sc decreases and the values of DT/Dm
gradually approach the line corresponding to `gas behaviour¿ (i.e. Sc ¿ 1), which is known to be
well approximated by the equation DT/Dm = 1/¿ + ud/12Dm, where ¿ is the tortuosity with
regard to diffusion
ER -