Effects of periodic perturbations on the oscillatory combustion of acetaldehyde

Abstract

Periodic perturbations are applied to the input rates of acetaldehyde and oxygen, one at a time, in the combustion of acetaldehyde in a CSTR. We measure periodic responses in five entrainment bands as we vary the frequency and amplitude of the external periodic perturbation. Outside of entrainment bands we find quasiperiodic responses. Next-phase maps of the experimental results are constructed in real time and used in the observation and interpretation of entrainment and quasiperiodic behavior. Within the fundamental entrainment band, we measure critical slowing down and enhancement of the response amplitude. As the bath temperature is increased, so that the oscillatory system approaches a Hopf bifurcation, we observe an increase in the amplitude enhancement. The predictions of a five-variable thermokinetic model agree with the experimental results.