The Research Of Heat Release Rate And Backlayering In The Fire Under The Metal Mine

Fire is one of the most dangerous disasters in metal mines.The heat release rate of the fire is very valuable to be researched as an important parameter to represent fire scale and fire intensity in underground fire.The smoke which is toxic and in a harmful high temperature produced by underground fire not only damages the equipments underground and affects normal production,but also threatens personal safety of workers.The smoke generated from underground fire will not only enter the production space of the downwind direction,but also form the counter flow of smoke into the tunnel.It is very important for fire rescue to master the rule of smoke countercurrent.The main research work of this article,which focus on the heat release rate and the law of the backflow of the smoke in the fire of underground mine,combines the numerical simulation,the experimental verification and the theoretical analysis,is listed below:It validates the feasibility of the new function from FDS6 and later versions to study the fire heat release rate by thermal decomposition model,and it is applied to simulate the influence of ventilation factors and roadway conditions on the heat release rate of roadway fire.The following conclusions are what we got:The heat release rate increases linearly with the increase of wind speed when the wind speed is within the range of 1-8m/s,beyond this range,the increase of wind speed will make the heat release rate of fire stable at a very small value.Within a certain range,the heat release rate increases with the increase of wind volume,and over a certain range,the heat release rate decreases.The heat release rate is stable at larger values in the range of 1.1-1.4 of roadway width to height,and the heat release rate is stable of roadway width to height is stable at smaller value than that of this range.When the fires are at different heights,the heat release rate finally stabilized at the similar value.The influence of the fire power,wind speed and fire source position on the law of fire smoke counter flow in the slope is studied by using the simplified slope model of the mine tunnel.It is known that the change of fire power and wind speed will change the relationship between L/H and the dimensionless parameters Q*/V*3 in natural logarithm.If the counter flow of smoke meets the point of intersection between the middle section and the sloping ramp,the countercurrent will mainly enters the middle section when the horizontal velocity of the counter current is the same as the middle section,and conversely,the countercurrent will mainly goes up the slope along the slope.The same way is used to study the law of fire smoke counterflow in the middle section.It is known that the change of fire power and wind speed in the middle section will change the relationship between L/H and the dimensionless parameters Q*/V*3 in natural logarithm.When the ramp gradient increases,the counter flow length of fire smoke gradually decreases.If the location of the fire source is closer to the slope and the wind speed is larger in the inclined slope,the smoke of the middle section of the fire will not enter the upper slope of the ramp when it reaches the intersection of the middle section with the ramp.On the contrary,a part of counter flow smoke will spread to the top of the ramp when the ramp wind speed is smaller.