Experimental and LES investigation of premixed methane/air flame propagating in a tube with a thin obstacle |
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Authors: | Peng Chen Shilong Guo Yanchao Li Yutao Zhang |
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Institution: | 1. State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology-Beijing, Beijing, 100083, PR China;2. School of Resources &3. Safety Engineering, China University of Mining and Technology-Beijing, Beijing, 100083, PR China;4. School of Resources & |
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Abstract: | In this paper, an experimental and numerical investigation of premixed methane/air flame dynamics in a closed combustion vessel with a thin obstacle is described. In the experiment, high-speed video photography and a pressure transducer are used to study the flame shape changes and pressure dynamics. In the numerical simulation, four sub-grid scale viscosity models and three sub-grid scale combustion models are evaluated for their individual prediction compared with the experimental data. High-speed photographs show that the flame propagation process can be divided into five stages: spherical flame, finger-shaped flame, jet flame, mushroom-shaped flame and bidirectional propagation flame. Compared with the other sub-grid scale viscosity models and sub-grid scale combustion models, the dynamic Smagorinsky–Lilly model and the power-law flame wrinkling model are better able to predict the flame behaviour, respectively. Thus, coupling the dynamic Smagorinsky–Lilly model and the power-law flame wrinkling model, the numerical results demonstrate that flame shape change is a purely hydrodynamic phenomenon, and the mushroom-shaped flame and bidirectional propagation flame are the result of flame–vortex interaction. In addition, the transition from “corrugated flamelets” to “thin reaction zones” is observed in the simulation. |
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Keywords: | methane/air flame LES sub-grid scale viscosity models sub-grid scale combustion models flame–vortex interaction |
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