Knudsen flow

Input(s)

m: Molecular Mass (g)

$\mathrm{K}$: Boltzmann Constant $\left(\mathrm{m}^{2} \mathrm{~kg} \mathrm{~s}^{-2} \mathrm{~K}^{-1}\right)$

$\mathrm{T}$: Temperature (Kelvin)

R: Radius (m)

po: Pressure at Initial point $(\mathrm{Pa})$

pL: Pressure at point $\mathrm{L}(\mathrm{Pa})$

L: Length (m)

Output(s)

w: Mass Rate Flow $(\mathrm{kg} / \mathrm{s})$

Formula(s)

$$ w=\operatorname{sqrt}\left(2 * \frac{m}{K * T}\right) *\left(\frac{4}{3} * R^{3}\right) * \frac{p o-p L}{L} $$

Reference(s)

Wikipedia.org.