M-1 Molecular Diffusion in fluids

Concentration , velocity, flux

mass fravtion of A

taotal molar concentratin C

Molar fraction

MAss averager velocity for a multicomponent mixture mass densitues

molar average velocity for a multicomponent

mass/molar flux

Mixture average velocity

molar diffusion flux

Relation b/w mass flux ni and mass diffusion flus Ji

molar flux Ni --- molar diffusion flux Ji

Molar flux Ni

Ficks first law of diffusion

Diffusion coefficient for binary ideal gas sysytems.

Diffusivity of liquids-

euation of continuity and ficks 2nd law

Multicomponent diffusitvity and derivation

Molecular diffusion in gases

Steady state diffusion of A through nondiffusing B

Staedy state equimolar counterdiffusion-

molercular diffusion liquids

Diffusion in solids

convective mass transfer

Staeady state diffusion of A through nondiffusing B

steady state equimolar counterdiffusion

Steady state diffusion in solids

diffusion through crystalline solids

diffusion in porous solids

Knudsen number

Knudse diffusion in porous solids.

Graham law of effusion for knudsen diffusion of a multicomponent system at constant total pressure.

unsteady -state diffusion

Diffuion from a slab with sealed edges

Diffusion from a rectangle bar with sealed ends

Diffusion fro a rectangular parllelepiped

Diffusion from a spher

Diffusion from a cylinder with sealed ends

Diffusion from a cylinder

Mass transfer coefficents

Equimolar counterdiffusion

for gases

For liquids

Relation b/w mass transfr coefficients.

Theories of mass transfer

Flim theory

The film theory is based on the following assumptions;.

Mass transfer at fluid surfaces.

penetration theory

surface -renewal theories

combination flim -surface renewal theory

surface stretch theory

interphase Mass transfer

equilibria

diffusion b/w phases

local two-phase Mass transfer

Local overall mass transfer coefficients

local coefficeint general case-

for the two important special caes-

diffusion of one component

equimolar counter diffusion

generalizied relation b/w K-type of mass tranfer coeffficeients

Analogics among molecular transport phenomena

Dimensionless groups of heat and mass transfer

The limation for converting replacing the group are