Editing Mass transfer (section)

==Analogies between heat, mass, and momentum transfer==
{{main|Transport phenomena (engineering & physics)|l1=Transport phenomena}}
There are notable similarities in the commonly used approximate differential equations for momentum, heat, and mass transfer.<ref name="basictext"/> The molecular transfer equations of [[Newtonian fluid|Newton's law]] for fluid momentum at low [[Reynolds number]] ([[Stokes flow]]), [[Heat conduction|Fourier's law]] for heat, and [[Fick's laws of diffusion|Fick's law]] for mass are very similar, since they are all [[linear approximation]]s to transport of conserved quantities in a flow field. 
At higher Reynolds number, the analogy between mass and heat transfer and momentum transfer becomes less useful due to the [[nonlinearity]] of the [[Navier–Stokes equation]] (or more fundamentally, the [[Momentum#Relating to force – general equations of motion|general momentum conservation equation]]), but the analogy between heat and mass transfer remains good. A great deal of effort has been devoted to developing analogies among these three transport processes so as to allow prediction of one from any of the others.