Modelling complex oscillations for the H2+ O2 reaction in an open system

Abstract

The complex waveforms observed in the oscillatory ignition of a stoichiometric H2–O2 mixture in a well stirred, continuous-flow reactor are modelled using a 35-reaction Baldwin–Walker mechanism. The behaviour of this reaction is further studied through a series of reduced mechanisms of 17, 13 and 10 steps, respectively. In each case, complex waveforms require the self-heating of this exothermic reaction to be included, whereas simple oscillations arise even with isothermal models. The methods of bifurcation theory are applied to the smallest of these models and suggest a close connection between parameter ranges for which the simple oscillations in the isothermal scheme change rapidly in period and amplitude with the conditions for complex oscillations in the full, non-isothermal model.