Chemical Instabilities. IV. Nonisothermal Chemical Surface Reactions and Hydrodynamic Instability

A linear stability analysis of a horizontal layer of the reactive fluid mixture (A2A) which is undergoing the surface catalyzed nonisothermal reaction (A2⇋2A) is performed. It has been found that including the heat of reaction in our analysis leads not only to a modification of the convective instability observed for the isothermal reactive fluid, but also to a whole new class of instabilities for fluids with negative (gravitationally stable) steady-state density gradients. This new class of instabilities resulting from the heat of reaction is referred to as “thermochemical” instabilities. The mathematically similar thermosaline evaporation problem, describing the evaporation of water from the surface of a salt solution, is also examined and found to exhibit similar stability characteristics.