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Mathematical Problems in Engineering
Volume 2015, Article ID 582963, 5 pages
http://dx.doi.org/10.1155/2015/582963
Research Article

Modelling Gas Diffusion from Breaking Coal Samples with the Discrete Element Method

1Department of Mathematics and Information Technology, Hanshan Normal University, Chaozhou, Guangdong 521041, China
2School of Engineering and Technology, Central Queensland University, North Rockhampton, QLD 4702, Australia

Received 13 November 2014; Accepted 19 January 2015

Academic Editor: Sebastian Anita

Copyright © 2015 Dan-Ling Lin et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Particle scale diffusion is implemented in the discrete element code, Esys-Particle. We focus on the question of how to calibrate the particle scale diffusion coefficient. For the regular 2D packing, theoretical relation between micro- and macrodiffusion coefficients is derived. This relation is then verified in several numerical tests where the macroscopic diffusion coefficient is determined numerically based on the half-time of a desorption scheme. To further test the coupled model, we simulate the diffusion and desorption in the circular sample. The numerical results match the analytical solution very well. An example of gas diffusion and desorption during sample crushing and fragmenting is given at the last. The current approach is the first step towards a realistic and comprehensive modelling of coal and gas outbursts.