Using the fully developed concentration profile to determine particle penetration in a laminar flow tube

•New analytical expression for particle penetration through laminar flow tube.•Excellent agreement with Gormle–Kennedy series solution.•Valid for dimensionless diffusion coefficient greater than 0.04.

A previously found analytical expression for the fully developed concentration profile of aerosol particles flowing through a circular tube under laminar conditions has been used to derived a simple analytical expression to determine particle penetration. The resulting expression, P=0.846exp(−3.659β) where β is the dimensionless diffusion coefficient of the particle, has been compared satisfactorily with the well-known Gormley–Kennedy equation even for values of β   as low as 0.04 in spite that, in principle, the approximate expression for the fully developed concentration profile is only valid for β>0.2β>0.2.