FREE-CONVECTION BOUNDARY-LAYERS ON VERTICAL SURFACES DRIVEN BY AN EXOTHERMIC SURFACE-REACTION

The free-convection boundary-layer flow on a vertical surface which re sults when there is an exothermic catalytic chemical reaction on that surface is discussed. The system is seen to be governed by the two dim ensionless chemical parameters epsilon and alpha which are measures of the activation energy and heat of reaction respectively, as well as t he Prandtl and Schmidt numbers. A series solution is obtained valid ne ar the leading edge of the plate and this is continued downstream by n umerical solutions of the full equations. The numerical solutions indi cate the criticality of the system by local rapid increases in the rea ction rate when epsilon and alpha are small. Asymptotic solutions vali d at large distances downstream are obtained and these are shown to be essentially different in character between the cases when alpha = 0 a nd when alpha not-equal 0. A singularity is seen to develop at a finit e distance downstream when both epsilon = 0 and alpha = 0, and this is analysed.