Module 3: Physics of Combustion
Lecture 12: Introduction
Fick's Law of Species Diffusion
Two parallel plates-separated by ‘Y'.
Upper plate is maintained wet.
Lower plate is kept dry (Dehydrating agent)
Water vapour evaporates at upper plate
Partial pressure of water vapour is maintained at saturated vapour pressure of water
Thus concentration gradient exists between the
two plates
Mass flux-proportional to concentration, C
A
inversely proportional to distance Y
Differential form of Fick's law
(Figure 12.3)
Binary diffusitivity of species A through B
