SUBGRID-SCALE MODELS FOR PREDICTING PREMIXED METHANE-AIR FLAME PROPAGATING IN A CHAMBER WITH A RECTANGULAR OBSTACLE
G. Luo1, L. J. Zhang2, J. Q. Fang3
1Zhejiang College of Security Technology, Department of Emergency and Technology, Zhejiang, PR China
2College of Safety Science and Engineering, Nanjing University of Technology, Nanjing, PR China
3School of Business, Wenzhou University, Wenzhou, PR China
Keywords: methane-air flame, large eddy simulation (LES), subgrid-scale viscosity models, subgrid-scale combustion models, flame-vortex interaction
Abstract
Experimental and numerical studies of premixed methane-air flame dynamics in an obstructed chamber are carried out. In the experiment, high-speed video photography and pressure transducer measurements are used to study the combustion dynamics. In the numerical simulation, three subgrid-scale viscosity models and three subgrid-scale combustion models are selected to evaluate their individual predictions compared to the experimental data. The high-speed photographs show that the flame propagation process can be divided into four typical stages. When the flame front passes through the obstacle, two distinct vortex structures are formed. The volute flame is the result of the flame-vortex interaction. In addition, the combustion regime experiences a transition from “wrinkled flamelets” to “corrugated flamelets” and finally arrives at a “thin reaction zone regime.”
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