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Transport phenomena in a catalytic monolith: Effect of the superficial reaction
Author(s) -
Di Benedetto A.,
Marra F. S.,
Donsi F.,
Russo G.
Publication year - 2006
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.10680
Subject(s) - exothermic reaction , nusselt number , heat transfer , thermodynamics , ignition system , chemistry , adiabatic process , damköhler numbers , perturbation (astronomy) , reaction rate , heat flux , mechanics , catalysis , physics , combustion , reynolds number , turbulence , biochemistry , quantum mechanics
The effect of a fast exothermic surface reaction on the fluid flow and on heat transfer between bulk gas phase, and the catalytic wall in a monolithic reactor has been studied by means of a 2‐D mathematical model. The radial profiles of temperature, concentration, and velocity in the ignition region show that the perturbation induced by the reaction is qualitatively comparable to the entrance effects. From the standpoint of heat transfer efficiency the channel may be divided into two zones, the first dominated by the entrance effects and the second dominated by the reaction effects. In the first zone the interphase heat transfer resembles the constant wall heat flux (Nu H ), while after ignition resembles the constant wall temperature (Nu T ) only once the perturbation generated by the reaction ignition has extinguished. It is, hence, showed that the Nu number may be calculated as the interpolation between Nu H , and a modified Nusselt number Nu ad , which is defined as a function of the difference between the adiabatic temperature and gas bulk temperature rather than wall‐gas temperature difference. It is anchored to the ignition location, depends on the operating and kinetic parameters and asymptotically tends to Nu T . © 2005 American Institute of Chemical Engineers AIChE J, 2006