3-D simulation of gases transport under condition of inert gas injection into goaf

• Published in: Heat and mass transfer Vol. 52; no. 12; pp. 2723 - 2734
• Main Authors: Liu, Mao-Xi, Shi, Guo-Qing, Guo, Zhixiong, Wang, Yan-Ming, Ma, Li-Yang
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2016; Springer Nature B.V
• Subjects: Asphyxia; Carbon dioxide; Coal mines; Computational fluid dynamics; Engineering; Engineering Thermodynamics; Gas injection; Gases; Heat and Mass Transfer; Industrial Chemistry/Chemical Engineering; Original; Oxidation; Porous media; Rare gases; Reservoirs; Simulation; Spontaneous combustion; Stress distribution; Thermodynamics; Coal Seam; Dangerous Zone; Oxidation Zone; Spontaneous Combustion; Mine Fire
• ISSN: 0947-7411; 1432-1181
• DOI: 10.1007/s00231-016-1775-8

To prevent coal spontaneous combustion in mines, it is paramount to understand O 2 gas distribution under condition of inert gas injection into goaf. In this study, the goaf was modeled as a 3-D porous medium based on stress distribution. The variation of O 2 distribution influenced by CO 2 or N 2 injection was simulated based on the multi-component gases transport and the Navier–Stokes equations using Fluent. The numerical results without inert gas injection were compared with field measurements to validate the simulation model. Simulations with inert gas injection show that CO 2 gas mainly accumulates at the goaf floor level; however, a notable portion of N 2 gas moves upward. The evolution of the spontaneous combustion risky zone with continuous inert gas injection can be classified into three phases: slow inerting phase, rapid accelerating inerting phase, and stable inerting phase. The asphyxia zone with CO 2 injection is about 1.25–2.4 times larger than that with N 2 injection. The efficacy of preventing and putting out mine fires is strongly related with the inert gas injecting position. Ideal injections are located in the oxidation zone or the transitional zone between oxidation zone and heat dissipation zone.