Free convection boundary layers driven by exothermic surface reactions: critical ambient temperatures

Abstract

A model for the free convection boundary-layer flow near a forward stagnation point driven by heating from a surface on which there is a catalytic reaction is discussed. The governing equations are mude dimensionless so as to highlight the ambient temperature with themain emphasis being to determine critical ambient temperatures. The basic model is then reduced to a standard free convection problem by a transformation of variables from which bifurcation diagrams (plots of a dimensionless surface temperature against a dimensionless ambient temperature) can be constructed. These show a hysteresis bifurcation, the position of which can be readily deduced. A feature of the present formulation is the occurrence of disjoint bifurcation diagrams whereby the upper solution branch becomes separated from the lower solution branches. This aspect is also discussed in detail.