Effective Diffusivity in Porous Media

Effective diffusivity in porous media, abbreviated as \( D_e \), is the adequate dispersion of gas or liguid through the voids of soil.

 

Effective diffusivity in porous media formula

\(\large{ D_e =  \frac{ D \; n \; \delta }{ \tau }  }\)

Where:

Units	English	Metric
\(\large{ D_e } \) = effective diffusivity	\(\large{ \frac{ft^2}{sec} }\)	\(\large{ \frac{m^2}{s} }\)
\(\large{ D } \) = diffusion coefficient in gas or liquid filling the pores	\(\large{\frac{ft^2}{sec}}\)	\(\large{\frac{m^2}{s}}\)
\(\large{ n }\) = porosity available for transportation	\(\large{dimensionless}\)
\(\large{ \delta }\)  (Greek symbol delta) = constrictivity	\(\large{dimensionless}\)
\(\large{ \tau } \)  (Greek symbol tau) = tortuosity	\(\large{dimensionless}\)