Research On Smoke Flow And Distribution Of Conveyor Belt Fire In Coal Mine

Coal resources take an important position in China’s energy consumption structure as the coal-rich,oil-less and gas-starved energy pattern,and it will not be changed in the long term.Such huge amount of coal production has made belt conveyors widely used in coal mine.Once a fire accident occurs when belt conveyors are used as the hub of coal transportation systems,not only is the fire developing faster than other types of fire,but also the large amount of poisonous and harmful fumes produced by the burning of conveyor belt seriously threat the safety of miners.Based on the urgent needs of coal mine in the study of fire safety systems,basic application studies on fire problems are of great significance in the prevention of roadway fire,the reduction of fire damage,the protection of personnel safety,and the safe production of coal resources.Based on the analysis and summary of previous research results,a combination of full-scale model experiment and FLUENT numerical simulation were used to analyze the distribution law of smoke temperature and CO concentration during the conveyor belt fire in transportation laneway.The main conclusions of this thesis are as follows:(1)Based on the full-scale conveyor belt fire experiment platform,the temperature in the upper space of the roadway is higher than the temperature in the lower space,and the temperature increase process in the remote area from the fire source lags behind the temperature increase process in the area close to the fire source.Then the temperature of the smoke in roadway axial plane is lower than the temperature of the smoke at the two waists of the roadway.(2)According to the experimental results,the vertical and longitudinal diffusion law of CO concentration in the roadway during the conveyor belt fire was obtained,and the CO diffusion law was summarized into three stages: slow growth,rapid growth and attenuation.(3)The error analysis of the full-scale experimental results and numerical simulation results verified the feasibility and rationality of the FLUENT software for smoke movement simulation of conveyor belt fire in roadway.Based on this,the established numerical model was applied to conveyor belt fire in roadway for predictive research.(4)The numerical simulation study was conducted on the spread of smoke from conveyor belt fire under conditions of ventilation rates of 0.4m/s,0.8m/s,1.2m/s,1.6m/s,and 2.0m/s.The results show that when the ventilation rate is lower than 1.2m/s,obvious countercurrent phenomenon of smoke will occur in roadway,and with the increase of ventilation rate,the occurrence of the countercurrent phenomenon can be suppressed.(5)With the increase of the ventilation rate,the temperature in the roadway will gradually decrease,and the gradient of the temperature decrease near the fire source will be greater than the gradient of temperature decrease in the remote region of the fire source.(6)The concentration of CO near the fire source area is higher than the CO concentration away from the fire source area,and the gradient of the decrease of CO concentration near the fire source area with increasing ventilation rate is larger than the gradient of CO concentration decrease away from the fire source area.