INTENTIONAL MANIPULATION OF CLOSED-LOOP TIME-DELAY FOR MODEL VALIDATION USING FEEDBACK-INDUCED BIFURCATION

Hopf bifurcation of a simple isothermal stirred tank without reaction is possible through the introduction of time-delayed feedback. By manipulating the time delay and a single feedback gain as bifurcation parameters, sensitive experiments were performed to test the validity of a model that describes the dynamic behavior of the combined components in an experimental gas-phase reactor flow system. Experimental bifurcations to sustained oscillations show that the stability of the reactor system is strongly influenced by delay. The relationships of time delay to Hopf bifurcation gains and frequencies provide a very sensitive basis for model comparisons. These type of comparisons are used to demonstrate the accuracy of the proposed model for the experimental system. The effect of noise and data sampling rate are then investigated by numerical simulation with the model. The complete model is necessary for analyzing bifurcation experiments including the effects of catalytic reaction.