OP-II-3

PP-I-15THE MECHANISM OF SELF-OSCILLATIONS GENERATION IN CSTR.CONSECUTIVE REACTIONDeyun Е.V., Andrianova Z.S., Kustova L.V., Samoilenko N.G.,Korsunskiy B.L.Institute of Problems of Chemical Physics of the Russian Academy of Sciences.Academician Semenov avenue, 1, 142421 Moscow region, Chernogolovka, Russia.E-mail: kors36@mail.ruThe mechanism of self-oscillation generation and damping in CSTR with twoconsecutive exothermal first order reactions has been studied. It has been shown,that in the system with only one steady state oscillations arise “softly” on the lowerborder of self-oscillatory modes (small values of Semenov parameter) but on theupper border (great values of Semenov parameter) oscillations damp "rigidly", i.e. thestable limiting cycle merges with an unstable one.For adiabatic reactor the impossibility of existence of the closed trajectories inphase space has been proved.In contrast to autocatalytic and concurrent reactions, in the case of consecutivereactions the occurrence not only оf one and three, but also of five steady states isprobable. The area of five steady states arises inside of the area of three steadystates. When the relationship between activation energies of separate stages ischanged the part oh this area penetrates through the upper border turning into anadditional subarea of three steady states.The mechanism of self-oscillations generation for the cases of three and fivesteady states has been investigated. For the purpose in parametrical space Se - Da(Se – Semenov criterion, Da – Damköhler criterion) the areas of steady statesmultiplicity have been calculated. The analysis of steady states transformation andself-oscillations generation inside multiplicity areas has allowed proposing themechanism of a "rigid" birth of a stable limiting cycle (a mathematical image of selfoscillations).This mechanism is founded on the formation of saddles-knotstrajectories loop.246