Development of compact kinetic mechanism for high temperature oxidation of methyl methacrylate
Speaker: Mr. Shanmugasundaram D.
Abstract
Synthetic and natural polymeric esters find applications in transport and construction sectors, where fire safety is an important concern. One polymer that is widely used is poly (methyl methacrylate) (PMMA), which almost completely undergoes thermal de- composition into methyl methacrylate (its monomer) (MMA) at 250-300◦ C. In order to analyze the high temperature gas phase oxidation of PMMA, and thereby predict its fire behaviour with less computational effort, a compact kinetic mechanism for the oxidation of its primary decomposition product, MMA, is most essential. This is ac- complished in the present work by obtaining a reduced mechanism for MMA oxidation from a detailed mechanism. Evaluating this mechanism against MMA premixed flame datasets and laminar burning velocities point to the need to revise the kinetic mecha- nism, which is achieved by adopting rate constants of key reactions among analogous molecules from recent literature. The updated compact kinetic mechanism is able to predict the major species in the flat flame as well as the burning velocity of MMA satisfactorily. This short MMA mechanism consists of 88 species and 1084 reactions.
The 2-D numerical simulation with the developed mechanism is not possible due to the limitation posed by numerical solver in handling number of species. Thus, a compact mechanism of 50 species and 320 reactions is obtained from the short MMA mech- anism using DRGEPSA reduction technique. The 50 species mechanism predictions of major and intermediate species in premixed flat flames as well as burning velocities agrees well with the 88 species mechanism. Importance of target tolerance in predict- ing the amount of intermediates are emphasized using flux and sensitivity analysis. This ”50 species mechanism” can be utilized to carry out further CFD computations.