Our objective in this section is to determine mixture properties from the pure species properties. In the case of viscosity, we use the semi-empirical formula due to Wilke [45] and modified by Bird, et al.[33] The Wilke formula for mixture viscosity is given by

(5–49)

where

(5–50)

for the mixture-averaged thermal conductivity we use a combination averaging formula [46]

(5–51)