# Diffusion through a stagnant film

## Input(s)

$$\boldsymbol{D}_{\boldsymbol{A} \boldsymbol{B}}$$: Diffusivity $$\left(\mathrm{cm}^{2} / \mathrm{s}\right)$$

$$z_{1}$$: Initial Position (ft)

$$z_{2}$$: Output Position (ft)

$$\boldsymbol{x}_{\boldsymbol{A} 1}$$: Mole Fraction of A1 $$(\mathrm{g} / \mathrm{ft})$$

$$\boldsymbol{x}_{\boldsymbol{A} 2}$$: Mole Fraction of A2 $$(\mathrm{g} / \mathrm{ft})$$

$$x_{b}$$: Mole Fraction of B in the Logarithmic Mean of Thermal Concentrations (mol/ft $$\mathrm{t}^{3}$$ )

c: Total Molar Concentration $$\left(\mathrm{mol} / \mathrm{ft}^{3}\right)$$

## Output(s)

$$\mathrm{N}$$: Combined Molar Flux $$\left(\mathrm{mol} / \mathrm{ft}^{2} \mathrm{~s}\right)$$

## Formula(s)

$\mathrm{N}=\frac{\mathrm{c} * \mathrm{D}_{\mathrm{AB}} *\left(\mathrm{x}_{\mathrm{A} 1}-\mathrm{x}_{\mathrm{A} 2}\right)}{\left(\mathrm{z}_{2}-\mathrm{z}_{1}\right) *\left(\mathrm{x}_{\mathrm{b}}\right)}$

## Reference(s)

Bird, R.B., Stewart, W.E. and Lightfoot, E.N. (2002). Transport Phenomena (Second Ed.). John Wiley & Sons, Chapter: 18, Page: 548 .

## Related

### Diffusion through a stagnant gas film

An unhandled error has occurred. Reload 🗙