viscosity

> Question - Is there a reliable formula for predicting the viscosity > of a mixture >of disparate (by mass) gases? If so, what is it? Specifically, I >would like a reliable means for calculating the viscosity of a mixture >of helium and xenon. The xenon appears in trace amounts (concentrations >by number density ranging from 1% to 8%). I am familiar with several >kinetic-theory-based formulas, but I am concerned about their validity >when applied to this disparate gas mixture.-------------------------------------------------------------------------- If you are familiar with a kinetic-theory formula set up formixtures, I'd go for it. The difference in masses (and morerelevantly polarizabilities) will turn up in the collision integralsthat you need to calculate or look up, and not in the kinetics theory,it seems to me. So if you trust your kinetics theory for the plainhelium, I can see no reason to distrust it for the mixture, if youdon't fudge the collision integrals. This problem has surely been dealt with, long ago. Try Curtiss,Hirschfelder, and Bird for further kinetics theory references, and seewhere the reference trail in Science Citation Index takes you. You could also easily do a molecular dynamics simulation, but forthe most accurate results you're going to need to worry about yourpotentials. Wouldn't it be easier just to measure the viscosity?? Grayce==================================================