Effects of two periodic perturbations on the oscillatory combustion of acetaldehyde

Periodic perturbations are applied to the input rates of acetaldehyde and oxygen simultaneously in the combustion of acetaldehyde in a CSTR. With the two perturbations at the same frequency, we measure bistability in entrainment and hysteresis as a function of the phase shift between the two perturbations. The application of a perturbation in the flowrate of one reactant to the system already entrained to a perturbation of the flowrate of the second reactant can cause the system: to become quasiperiodic in both perturbations; to become entrained to both perturbations; to remain entrained, but not phase locked, to the first perturbation; or to become quasiperiodic in the first perturbation but entrained to the second perturbation. We measure the effects of frequency modulated and amplitude modulated acetaldehyde flowrate perturbations; the results compare well with predictions made by a five-variable thermokinetic model.