Mean Free Path

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1. Mean Free Path
2. Diffusion, Thermal conductivity, and Viscosity

2006-10-12
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Equilibrium distribution
dn is the number of molecules
near v
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Meaning of dn/N
among N molecules, how many are near v
probability that one molecule is near v
proportional to dvx ...
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Isotropic assumption
The solution is
The probability should be normalized
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each normalized
a
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For unit volume
Maxwell velocity distribution
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Maxwell speed distribution
Most probable speed
For one molecule, what speed is most possible?
Among N molecules, what is the speed most
molecules have in unit interval?
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Maxwellian can be written as
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The average speed
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Transport phenomena
Heat transfer
conduction convection
thermal radiation
diffusion
viscosity
thermal conductivity
Fouriers law
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Diffusion
Ficks law
Viscosity
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Microscopic theory of transport coefficients
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Similarly
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Hydrogen under STP
r 1.1210-10m
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Experimental results