Dynamic Shape Factors for Binary Diffusion of Organic Compounds in Air

This work determines the dynamic shape factor for organic compounds diffusing in dry air at normal conditions T=298 [K] and P=1 atm. Aerosol theory is used to adapt the functional form of the slip correction factor as a function of the molecular Reynolds number. A simple power law expression is then developed for different classes of linear organic molecules using Valence Shell Electron Pair Repulsion theory and coefficients are found by fitting existing experimental and numerical data. These results are compared to widely used semi-empirical techniques to show their accuracy in determining binary diffusion coefficients with a mean deviation of 4% for organic compounds diffusing in dry air at normal conditions.