DRGEP-based mechanism reduction considering time dependency of reaction rate

Abstract

Importance of the method to determine interaction coefficient in the DRGEP method is explored by considering the pyrolysis reaction with time variation of temperature. To take into account time dependency, the interaction coefficients were determined using four different methods: the original method and three alternative methods. Two of the three alternative methods use the overall interaction coefficient computed from direct interaction coefficient determined by maximum value of ratio of production rate in each time, and the overall interaction coefficient computed from direct interaction coefficient determined by the averaged value of ratio of production rate in each time, respectively. The other method considers overall interaction coefficient computed from time-dependent direct interaction coefficient. The analytical condition for the mechanism reduction and the assessment of reduction accuracy are the pyrolysis of the gas composed of C2H2, C2H4, and N2 at 1000–1600 K and 0.1 MPa. The concentration of benzene during the simulation by the reduced mechanism was compared with original mechanism. In case of the DRGEP with method, the smallest reduced mechanism with accuracy has 60 species. In contrast, the reduced mechanisms constructed by the DRGEP with the latter two methods of the four accurately predict the concentration with only 45 species. In particular, the method that takes into account the time dependence of the reaction rate was able to describe the behavior in which the formation rate of the target chemical species, benzene, gradually approaches zero near equilibrium, even when the number of chemical species is 40.

Keywords

• DREGP
• Mechanism reduction
• Detailed kinetic mechanism