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

Abstract

Gaseous explosions are one of the most hazardous incidents in process and mining industries. Experimental research in this area is shown to be high risk and expensive. Computational Fluid Dynamics (CFD) techniques are reasonable alternatives to experiments; specifically when testing large scale gaseous explosions such as methane explosion in underground mines. The dimensions of a confined space where explosions could occur vary significantly. Thus, the scaling effect on explosion parameters is worth to be investigated using CFD tools. In this research paper, the impact of scaling on the explosion overpressures is investigated by employing two scaling factors. These two factors are the Gas-fill Length scaling factor (FLSF) and the Hydraulic Diameter scaling factor (HDSF). The combinations of eight HDSFs (1,2, 4, 8, 16, 32, 64, and 100) and five HDSFs (0.5, 1, 2, 4, and 8) will cover a wide range of space dimensions where flammable gas could accumulate. Experiments were conducted to evaluate the selected premixed combustion and turbulence models. Large Eddy Simulation (LES) turbulence model was used because it shows accuracy compared to the widely used Reynolds' averaged models for the scenarios investigated in the experiments. Researchers also simulated methane explosions in both deflagration and detonation regimes using different numerical schemes. Three major conclusions can be drawn from the simulation results. (1) The overpressure increases with both FLSF and HDSF within the deflagration regime; (2) in an explosion duct with length to diameter ratio greater than 54, detonation is more likely to be triggered for stoichiometric methane/air mixture; (3) overpressure increases as an increment hydraulic diameter of a geometry within deflagration regime.

Meeting Name

2015 SME Annual Conference and Expo and CMA 117th National Western Mining Conference - Mining: Navigating the Global Waters (2015: Feb. 15-18, Denver, CO)

Department(s)

Mining Engineering

Keywords and Phrases

Combustion; Computational fluid dynamics; Detonation; Explosives; Intelligent control; Ionization of gases; Large eddy simulation; Methane; Turbulence models; Underground explosions; Combustion simulations; Experimental research; Gaseous explosions; Length to diameter ratio; LES; Methane-air combustion; Premixed combustion; Scale effects; Explosions; Combustion simulation

International Standard Book Number (ISBN)

978-1-5108-0124-0

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2015 Society for Mining, Metallurgy and Exploration, All rights reserved.

Publication Date

01 Feb 2015

Link to Full Text

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