ADIABATIC LAMINAR FLOW WITH RADIAL AND AXIAL DIFFUSION

Result

Comparing this result with the previous result where radial mass transport was neglected, it is evident that a larger diffusivity tends to flatten out the radial temperature profile close to the reactor wall. Recall from the last problem that all reactants close to the wall were consumed at an early stage and that no reactants could diffuse to that area because of the assumptions made. Here however, reactants are allowed to diffuse, making it possible for the exothermic reaction to continue to produce heat closer to the wall.

Therefore in the later part of the reactor, the area closer to the wall is not only heated up by conduction but also by the exothermic reaction.