Computational Fluid Dynamics Simulation of Oxygen Seepage in Coal Mine Goaf with Gas Drainage

Abstract

Mine fires mainly arise from spontaneous combustion of coal seams and are a global issue that has attracted increasing public attention. Particularly in china, the closure of coal workfaces because of spontaneous combustion has contributed to substantial economic loss. To reduce the occurrence of mine fires, the spontaneous coal combustion underground needs to be studied. In this paper, a computational fluid dynamics (CFD) model was developed for coal spontaneous combustion under goaf gas drainage conditions. The CFD model was used to simulate the distribution of oxygen in the goaf at the workface in a fully mechanized cave mine. The goaf was treated as an anisotropic medium, and the effects of methane drainage and oxygen consumption on spontaneous combustion were considered. The simulation results matched observational data from a field study, which indicates CFD simulation is suitable for research on the distribution of oxygen in coalmines. The results also indicated that near the workface spontaneous combustion was more likely to take place in the upper part of the goaf than near the bottom, while further from workface the risk of spontaneous combustion was greater in the lower part of the goaf. These results can be used to develop firefighting approaches for coalmines.

Distribution Characteristic and Migration Mechanism of Toxic Gases in Goafs during Close-Distance Coal Seam Mining: a Case Study of Shaping Coal Mine

“… 17 CFD numerical models are commonly used by scholars to study the self-heating evolution trend of residual coal in the goafs of longwall working faces under complex conditions. 18 , 19 Through CFD numerical models, researchers have calculated the distribution of the oxygen concentration and wind speed in goafs and then studied the air leakage law, gas distribution, and migration law in the goafs under complex conditions; 20 − 23 however, few scholars have studied the gas distribution and migration laws in goafs through field tests by measuring a large number of data obtained in the field. 24 Most research mainly relies on numerical modeling, and there is a lack of field tests, causing a large discrepancy between the two methods.…”

Characteristics of Airflow Migration in Goafs under the Roof-Cutting and Pressure-Releasing Mode and the Traditional Longwall Mining Mode

“…Gao et al 23 used the method of numerical simulations to obtain the gas concentration distribution law in the goaf of the mine, solved the problem of gas transfinite in the upper corner of the mining face, and optimized the nitrogen injection parameters. Shi et al 24 established a CFD model of coal spontaneous combustion under the conditions of gas drainage in the goaf, and numerically simulated the oxygen distribution in the goaf of a fully mechanized mining face. According to the simulation results, the spontaneous combustion zone area of the goaf is obtained, which provides a basis for formulating mine fire prevention measures.…”

A Discussion on the Effective Ventilation Distance in Dead-End Tunnels

“…Furthermore, Yuan and Smith [12] studied the low-temperature oxidation of coal using unsteady-state simulations. Likewise, Shi et al [13] developed a CFDs model for coal spontaneous combustion under goaf gas drainage conditions.…”