Extinguishing Underground Coal Seam Fires: Experimental and Numerical Investigations of Coal Fire Propagation

A natural hazard of underground coal seam fire has been known as a worldwide problem. It is accordingly urged worldwide to fight against the catastrophic Situation associated with coal seam fire. In North China, underground coal seam fires burned away around 20 million of coal annually and threatened environment and people in the vicinity. Therefore, in this paper extinguishing and fire prevention methodologies of underground coal fire have been devoted to Investigating coal tire at attempting on the extinguishing of coal seam Fire in North China. The work presented in this paper covered experimental and numerical means of the coal seam fire phenomenon. The experimental work investigated the velocity of coal fire propagation and the role of barrier materials in extinguishing fires. The fire extinguishing abilities of different barriers were conducted in a quasi adiabatic oven. It was found that a prevention of fire propagation by using barriers is promising only if both the heat and the oxygen transport are prevented. For this reason the barrier shall exhibit a low heat conductivity and permeability.. Furthermore, different aspects of fire extinguishing techniques were discussed in detail by means of numerical simulation. It is intended in this work that the application of numerical simulation validated by experimental work shall contribute a significant role to predict the velocity of coal fire propagation and highlight the rule of convection and diffusion effects on the coal fire propagation, The model in this paper demonstrates the application of a multiphysics coupling between fluid flow due to the existence of hydrodynamic phenomena in coal seam as a porous medium, and heat and mass transfer. Thus, the numerical models included five multiphysics models, namely Darcy law, diffusion. conductive heat transfer, coupled convection and conduction, and coupled convection and diffusion models. The model considered the self ignition process as a source of heat generation in the coal seam leading to coal seam fire. Subsequently, the generated heat in the burning coal seam is transported by natural convection and conduction. A comparison of experimental and numerical simulations was performed for the fire propagation characteristic. As shown for one typical case, the simulation results were predicted with good agreement of coal seam fire propagation.