Mass transfer between co-current fluid streams and boundary layer solutions

Approximate laminar boundary layer solutions for mass transfer across the plane interface between two co-current parallel fluid streams are derived in the form {A figure is presented} where p and q are not constants but are functions of U₂/U₁ and μ₂ρ{variant}₂/μ₁ρ{variant}₁. It is suggested that the boundary layer theory provides a more realistic physical picture than either the Lewis and Whitman stagnant film theory or the Higbie Penetration Theory.