EXCITABLE CHEMICAL-REACTION SYSTEMS IN A CONTINUOUS STIRRED TANK REACTOR

A methodology based on the use of CSTR to obtain experimental information on the threshold of excitation and response of excitable chemical systems to single and periodic forcing is described. The classical Belousov-Zhabotinskii (BZ) reaction mixture and a reaction mixture containing bromic acid were used to determine the excitation threshold with respect to AgNO3 pulse stimulations. Both periodic and aperiodic behavior were observed in both reaction mixtures and are evaluated in the form of excitation diagrams showing the dependence of the firing number on the forcing period. Excitation diagrams for both systems possess the form of the devil's staircase. Sequences of excitation diagrams for increasing stimulation amplitudes were used to construct the dependence of the firing number on amplitude and frequency of stimulations. "Two-pulse" and "three-pulse" methods are proposed for the evaluation of the phase excitation curves (PEC's). An iteration of the appropriate PEC then enables simulations of the full excitation diagram and thus prediction of the behavior of the continuously forced excitable system. Effects of noise are studied and generally satisfactory agreement between simulated and experimental excitation diagrams is demonstrated. © 1990 American Chemical Society.