Date of Award

1989

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Mechanical Engineering

First Advisor

Thomas W. Lester

Abstract

A numerical model was developed to simulate flat flames burning chlorinated methanes in a methane/air environment. The model uses a reaction mechanism containing 341 reactions and 58 species. A time-stepping solution with linearized source terms and a strict convergence criteria had to be developed to allow for convergence of the conservation equations. Simulations of ten flames were made, five simulations of dichloromethane/methane/air flames, and five simulations of carbon tetrachloride/methane/air flames. For each fuel type, simulations were performed at a constant molar Cl/H ratio of 0.3 for a stoichiometric flame, a fuel-rich flame, and a fuel-lean flame. The other simulations were made for a constant stoichiometry with varying Cl/H ratio. For dichloromethane, the fuel equivalence ratio, $\Phi$, was held at 0.8 while the Cl/H ratio was varied from 0.06 to 0.5, for carbon tetrachloride $\Phi$ was held at 0.95, while the Cl/H ratio was changed from 0.7 to 0.5. Comparisons to experiment were made for eight of the ten simulations. Available experimental data included the major species, and ten stable intermediates. The simulations are in good agreement with experiment for the major species profiles. The computational profiles for the stable intermediates are in good agreement with experiment for forty-eight percent of the seventy-nine computational species profiles compared to experiment. Seven percent of the comparisons are poor. These computational profiles have peak values that are more than a factor of ten larger or smaller than experiment. The simulation results were used to postulate reaction pathways for the combustion of dichloromethane, carbon tetrachloride, and methane. Burner effects were found to be important in the carbon tetrachloride flames.

Pages

226

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