A simple model for examining mixing of pumped stationary states

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Abstract
The oxidation of cerous ion by bromate has been approximated by four irreversible bimolecular processes. When this mechanism is modeled numerically in a continuously stirred tank reactor (CSTR), wide ranges of conditions generate two different stationary states that are stable indefinitely for identical values of the pumping parameters. By simultaneous variation of the residence time and reactant input, it is possible to move from one to the other of these states without any discontinuity in stationary state composition. If equal volumes of the two states are mixed while pumping is continued, one or the other will become dominant. The value of the residence time generating states of equal ’’dynamic stability’’ is grossly different whether the mixing is performed instantaneously by removing a barrier between those states or gradually by increasing sizes of holes in that barrier. Because relative ’’dynamic stability’’ is extremely dependent upon path even for a process as a simple as ’’ mixing’’, it appears doubtful that useful state functions can be developed to predict the direction of evolution of open systems pumped far from equilibrium.