Period doubling and chaos during the oscillatory ignition of the CO + O2 reaction

Abstract

Experimental observations of period doubling accompanying the oscillatory ignition mode of carbon monoxide oxidation in a well stirred flow reactor are reported. In the presence of 0.5% added H2 and with a mean residence time of 16 s, we find oscillatory ignition for conditions above the second explosion limit. Further into this ignition region, the oscillatory waveform develops through period-2, period-4 ignitions etc., finally under-going a full ‘subharmonic cascade’ into chemical chaos. We have also observed subsequent periodic windows (period-5 and period-3). Simple oscillations are re-established via an inverse sequence back to period-1 ignitions. Our data capture allows reconstruction of the corresponding attractors and limit cycles and the Fourier power spectra.