# Dynamic viscosity of gas mixture (appropriate estimation)

What estimation of the dynamic viscosity $$\eta = f(T)$$ $$([\eta] = \pu{Pa·s})$$ of the gas mixture components would you recommend during adsorption at a low temperature, approx. $$\pu{293 K}$$ to $$\pu{333 K},$$ and a relatively low pressure?

Gas mixture contains $$\ce{N2}$$ (the major component), $$\ce{CO2}$$ and $$\ce{H2O}$$ in the form of water vapor.

I assume the gas mixture to be ideal.

About a year ago, I use to calculate the dynamic viscosity using Lennard–Jones coefficients for a slightly different conditions if I recall correctly. However, I cannot find my calculations, hence I wanted to check whether using these coefficients would be relevant for such case.

• What is "gas separation" ?
– Karl
Dec 26 '20 at 22:00
• @Karl I referred to adsorption - corrected. Dec 27 '20 at 11:23
• Ah, OK. Still: I could make a lot of assumptions about the process you have in your mind, and then the question would make sense. But I'd rather you told us.
– Karl
Dec 27 '20 at 14:08
• See Bird, Stewart, and Lightfoot, Transport Phenomena, Chapter 1 for mixing rules to get viscosity. Dec 27 '20 at 14:23
• @ChetMiller Thanks, I think I got it by combining either Sutherland Equation with Herning-Zipperer Eq. or probably more precise Chapman-Enskog theory with Herning-Zipperer Eq. If I can ask you one more question... I can apply the Chapman-Enskog theory to obtain values of gas components/mixture conductivity $\lambda_k$ and binary diffusion $D_{AB}$. What would you recommend to use for molecular diffusion $D_m$, between two gases, which I need to obtain axial dispersion coefficient $D_{ax}$, which lumps all the negative effects on separation, thanks. (I'd neglect $H_2O$ in the first attempt.) Dec 28 '20 at 8:53