The Application of Model-Based Tests for Analysing the Consequences of Methane Combustion in a Mine Heading Ventilated Through a Forcing Air Duct

Abstract

One of the most hazardous thermodynamic phenomena occurring in mine headings is fires. One of the substances commonly present in those headings is methane – an easily combustible, odourless gas of natural origin. ethane is released into the mining atmosphere as a result of coal mining activities. Appropriate concentration levels of this gas and the presence of oxygen produce a mixture which can lead to methane combustion and explosion when in contact with an ignition source, such a spark. Both of these phenomena are extremely dangerous, especially in mine headings. The article presents the results of a numerical analysis concerning methane ignition, leading to an exogenous fire in a mine heading. The purpose of the analysis was to demonstrate the mechanism of occurrence and development of methane fires, as well as to determine their consequences. This is because such fires cause emission of harmful and poisonous gases with extremely high temperatures into the mining atmosphere. The model-bases tests of a methane fire were conducted using the “Partially Premixed combustion” (CFD) model. The analysis conducted helped to determine the distributions of speed, pressure and temperature of the air stream flowing through the region under analysis, as well as to specify the distributions of concentration levels for the combustion products (CO and CO2). The article also describes the aerodynamics of the combustion process, as well as the phases of emergence, development and disappearance of fires. The model developed and the boundary conditions adopted for the tests reflect the real-world mine heading. The test method prepared for methane fires and the results obtained may represent a significant source of information for the mine’s ventilation service teams.