Mass accommodation coefficients from penetration measurements in laminar tube flow

The theory for penetration of 'sticky' gaseous molecules through cylindrical tubes in laminar flow is presented and implications of the theory for measurements of mass accommodation coefficients are discussed. For the case where the inner tube walls are coated with a liquid, a criterion is developed which can be used to determine whether re-evaporation is likely to contribute significantly to measured penetration values. This criterion can be useful in designing experiments. It is concluded that laminar flow penetration measurements can be useful for measuring very small mass accommodation coefficients (<10^-4). The theory can also be used to design diffusion denuders when accommodation coefficients are known.