In this formula, Diffusion Coefficient (DAB) uses Convective Mass Transfer Coefficient & Film Thickness. We can use 3 other way(s) to calculate the same, which is/are as follows -
Diffusion Coefficient (DAB) = (Average Contact Time*(Average Convective Mass Transfer Coefficient^2)*pi)/4
Diffusion Coefficient (DAB) = (Convective Mass Transfer Coefficient^2)/
Surface Renewal Rate
Diffusion Coefficient (DAB) = (Instantaneous Contact Time*(Instantaneous Convective Mass Transfer Coefficient^2)*pi)