Steadystate diffusion through variable crosssectional area

1
Steady-state diffusion through variable
cross-sectional area
is constant varies depending on transfer area
Case 1 Sphere with outward diffusion of A in
stagnant B
2
Case 1 continued Integrating one gets
For low values of PA1 and PA2 i.e. when PBM ? P
3
Case 2 Tube of linearly increasing diameter
4
Measurement of diffusivity of gases
Method 1 Diffusion from narrow tube (based on
change in path length)
For unit cross-sectional area
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Method 2 Two bulb method (based on equimolar
counter diffusion)
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Prediction of gaseous diffusivity