| With increasing depth of mining, mine spontaneous combustion is increasinglyprominent, which seriously affects the safety of coal production. Because of a largerange of mined-out area, it is necessary for detecting the high temperature rangeposition to study the heat transfer law among crashed coal in the goaf. But themonitoring methods in field exist many deficiencies, such as complex, low accuracy.Development the simulation platform is one of the methods to study the heat transferlaw among crashed coal in the goaf. By calculating the similarity proportion,combined with the parameters of20103working face in the Wangjialing coal mine,the paper analysis and design the mined-out area height of the experimental platform,selected high temperature heat source and working face ventilation ways, and finallydescribes how to complete experimental platform system.Firstly, the theory of spontaneous combustion in goaf is elaborated,and thecontinuous equation, momentum equation and energy equation are derived to giveflow and temperature field mathematic model including entire region of goaf andworking face. And based on the mathematical model, similar relationship formulas arederived between prototype and experimental models. The similarity ratio of geometric,experimental material particle size, porosity, and internal heat source are determined.Secondly, the following parameters of working face are analyzed theoretically.(1)In order to design height of simulation platform, caving zone formed feature isdiscrebed in goaf. By analysed caving zone height measurement method andcalculation models of horizontal and near horizontal coal seam, combined with theparameters of working face, the general relationship between caving zone height andmining height is acquired.(2)The heat source formation mechanism and heat transferways between rock and coal are analysed in goaf. A single heat source and a pluralityof heat sources are arranged in experimental device.(3)The current commonventilation way of working face in mine and different ventilation ways have an effecton coal spontaneous combustion in goaf are analysed. The U-shaped and U+L shapedventilation ways are selected in the model, and based on the air quantity of actualworking face, three airflow value0.2m3/min,0.3m3/min,0.5m3/min are designed.Finally, we describe four parts structure and function of the experimentalplatform including test box, temperature control system, ventilation control systemand data monitoring system. |
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