Scale Effect of Premixed Methane-Air Combustion in Confined Space Using LES Model

Minerals

Liang Wang¹  Sisi Que³  Jerry C. Tien⁴  Nassib S. Aouad² 

[1] State Key Lab of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 404000, ChinaMining and Nuclear Engineering Department, Missouri University of Science and Technology, Missouri, MO 65409, USA;School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing 404000, China;Faculty of Engineering, Monash University, Melbourne, Victoria 3800, Australia;

关键词: scale effect;    gaseous explosion;    Large Eddy Simulation (LES);    combustion simulation;   

DOI  :  10.3390/min6010002

来源: mdpi

【 摘 要 】

Gas explosion is the most hazardous incident occurring in underground airways. Computational Fluid Dynamics (CFD) techniques are sophisticated in simulating explosions in confined spaces; specifically, when testing large-scale gaseous explosions, such as methane explosions in underground mines. The dimensions of a confined space where explosions could occur vary significantly. Thus, the scale effect on explosion parameters is worth investigating. In this paper, the impact of scaling on explosion overpressures is investigated by employing two scaling factors: The Gas-fill Length Scaling Factor (FLSF) and the Hydraulic Diameter Scaling Factor (HDSF). The combinations of eight FLSFs and five HDSFs will cover a wide range of space dimensions where flammable gas could accumulate. Experiments were also conducted to evaluate the selected numerical models. The Large Eddy Simulation turbulence model was selected because it shows accuracy compared to the widely used Reynolds’ averaged models for the scenarios investigated in the experiments. Three major conclusions can be drawn: (1) The overpressure increases with both FLSF and HDSF within the deflagration regime; (2) In an explosion duct with a length to diameter ratio greater than 54, detonation is more likely to be triggered for a stoichiometric methane/air mixture; (3) Overpressure increases as an increment hydraulic diameter of a geometry within deflagration regime. A relative error of 7% is found when predicting blast peak overpressure for the base case compared to the experiment; a good agreement for the wave arrival time is also achieved.

【 授权许可】

CC BY   
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