Balancing Accuracy and Computational Cost: Evaluating Methane Combustion Mechanisms

This study compares different methane chemical combustion mechanisms with varying levels of complexity. The mechanisms studied include the widely used and accepted global mechanism WD2 with 2 reactions, and skeletal and detailed mechanisms SG35, Z42, DRM22, and GRI-3.0 with 35, 42, 104, and 325 reactions, respectively. The computational cost of the mechanisms was compared, with the results showing that the global mechanism WD2 was slower and converged more slowly compared to the skeletal mechanisms of similar size. The skeletal and detailed mechanisms showed increased cost with a power relationship to the number of reactions. The mechanisms were compared to experimental data to determine accuracy, with the Z42 mechanism found to be the best compromise between computational cost and accuracy, while the global mechanism WD2 had reduced accuracy and increased computational cost. The SG35 mechanism performed well in terms of speed, but with reduced accuracy. The study concludes that for more detailed information, postprocessing with GRI-3.0 is required.