Rayleigh–Benard convection in a chemically active gas in the chemical equilibrium state

Resumo

The Rayleigh–Benard convection in a chemically active gas in the chemical equilibrium state is numerically studied in the Boussinesq approximation. A flat layer with isothermal horizontal boundaries free from shear stresses is considered. Thermodynamic parameters of the gas (hydrogen–oxygen mixture) are calculated by the previously proposed model of chemical equilibrium. It is shown that the allowance for recombination and dissociation processes leads to the emergence of an additional factor at the Rayleigh number. An expression for the growth rate of infinitesimal perturbations and a relation for the critical Rayleigh number as a function of temperature are derived. It is found that the neutral curves consist of the upper (instability due to heating from below) and lower (instability due to heating from above) branches. Results calculated for a nonlinear steady mode are reported.