【作者】 齐峰；

【导师】 毕明树；

【作者基本信息】 大连理工大学 ， 安全技术及工程， 2008， 硕士

【摘要】 近些年来我国煤炭行业矿井瓦斯煤尘爆炸事故频繁发生。而几乎所有的爆炸情况下都存在设备、机械等大量的障碍物,正是这些障碍物的存在,增大了爆炸的威力,造成了更大的损失。要防止煤尘与可燃气体混合物的爆炸,首先要确定煤尘和燃气混合物的爆炸威力和特性,而目前对于含杂混合物煤尘爆炸,尤其是障碍物对瓦斯-煤尘混合物爆炸影响的研究还比较少。本文针对有障碍物存在条件下甲烷—煤粉混合物的爆炸特性进行了实验研究。本次研究的主要工作和结论如下:(1)根据标准设计了一套可抽式障碍物粉尘-燃气爆炸实验装置系统,实现了对煤尘、甲烷、障碍物参数的控制和对爆炸压力波、最大爆炸压力、最大压力上升速率以及爆炸时间等粉尘爆炸特性参数的实验测试。(2)障碍物对煤尘-甲烷爆炸具有显著的加速效果,与没有障碍物相比,有障碍物存在时,爆炸时间从70ms减少到约20ms:压力波在管道中传播的加速机理,主要应归因于障碍物诱导的湍流对燃烧过程的正反馈。(3)研究了障碍物结构、障碍物位置、障碍物数目、障碍物阻塞比对最大爆炸压力,最大压力上升速率以及爆炸时间在管道中的变化情况的影响。从研究的六种不同形状的障碍物来看,正方形障碍物具有最大的爆炸增速作用,圆形障碍物的增速效果最差,三角形的增幅效果处于它们之间:当障碍物之间间距接近管径长时,管内具有最大的压力上升速率;当障碍物个数为15个时,管内出现最大爆炸压力和最大压力上升速率;当阻塞率k为0.5时,爆炸压力和压力上升速率最大。(4)研究了甲烷—煤粉混合物组成特性对爆炸的影响。随煤粉粒径的减少,最大爆炸压力和最大压力上升速率都增加;随着煤粉浓度的增加,最大爆炸压力和最大压力上升速率先增加后减少,并在500g/m~3时它们都达到最大值;随着甲烷浓度的增加,最大爆炸压力和最大压力上升速率都先增加后减少,在甲烷体积分数约为6—7%时,管内出现最大爆炸压力和最大压力上升速率的最大值。本文的创新点:(1)对管道内存在障碍物时甲烷-煤粉混合物的爆炸特性进行研究,获得了障碍物形状、尺寸、数量等对爆炸特性的影响规律。即从研究的六种不同形状的障碍物来看,正方形障碍物具有最大的爆炸增速作用,圆形障碍物的增速效果最差,三角形的增幅效果处于它们之间;当障碍物之间间距接近管径长时,管内具有最大的压力上升速率;当障碍物个数为15个时,管内出现最大爆炸压力和最大压力上升速率;当阻塞率k为0.5时,爆炸压力和压力上升速率最大。(2)煤尘-甲烷混合物爆炸实验结果表明,煤尘粒径越小,爆炸威力越大;煤尘浓度为500g/m~3、甲烷浓度为6-7%时,爆炸威力最大。更多还原

【Abstract】 More and more explosions of gas and coal-dust occurred frenquently in recent years. There are lots of obstructions such as apparatus and machines etc. almost in all explosions locales. The obstructions make explosion more powerful and loss greater. In order to prevent the explosions of coal-dust and combustible gas, the explosion power and characteristics of the mixtures must be confirmed firstly. But the studies on the mixtures explosion especially the explosive effect of obstruction on methane-coal dust mixtures are few. The explosion characteristics of methane-coal-dust aiming at having obstructions and having no obstructions were studied experimentally in this paper. The main work and conclusions are as follows:(1) The experimental system of obstruction twitched coal-dust-gas explosion equipment was set up according to the standard. The equipment could control coal-dust, methane and obstruction parameters, explosion pressure, the maximum pressure rising rate and explosion time etc.(2)The obstructions accelerated remarkabaly the explosion of coal-dust-methane. Comparing with no obstruction, the explosion time decreased from 70ms to 20ms; accelerating mechanism of pressure wave in pipeline is that the positive feedback between overfall obstruction inducing and inflammation.(3) The effects of structure, position, amount, block-rate of obstruction on the maximum explosion pressure, the maximum pressure rising rate and explosion time in the pipeline were studied. In six different shapes obstructions, the square has the most ability to accelerate and the rotundity has the least ability and the triangle has the middle ability to accelerate. When the distance of obstructions is approaching to the diameter of the pipeline, the pressure rising rate reached the maximum. When the amount of obstructions is 15, the pressure and the pressure rising rate both reached the maximum, respectively. When the block-rate of obstruction reach 0.5, the pressure and the pressure rising rate also both reached the maximum, respectively.(4) The effects of composion of methane and coal-dust on explosion were studied. With coal-dust particular size decreasing, the maximum explosion pressure and maximum pressure rising rate increased, and; with coal dust concentration increasing, the maximum explosion pressure and maximumrate pressure rising rate increased first then decreased, and when the concentration was 500g/m~3, the both reached the maximum; with the methane concentration increasing, the maximum explosion pressure and maximum pressure rising rate increased first then decreased, and when the methane concentration was 6-7%, the maximum explosion pressure and maximum pressure rising rate reached the maximum.The main ideas are presented in this paper are as follows:(1) The paper has studied the explosion characteristics of methane-coal dust mixtures with obstructions in the pipeline, and the explosion characteristics affected by shapes, size and amount etc. of obstruction has been gotten. In six different shapes obstructions, the square has the most ability to accelerate and the rotundity has the least ability and the triangle has the middle ability to accelerate. When the distance of obstructions is approaching to the diameter of the pipeline, the pressure rising rate reached the maximum. When the amount of obstructions is 15, the pressure and the pressure rising rate both reached the maximum, respectively. When the block-rate of obstruction reach 0.5, the pressure and the pressure rising rate also both reached the maximum, respectively.(2) The results indicated the smaller coal-dust particular was, the bigger the explosion power, and when the concentrations of coal-dust and methane were 500g/m~3 and 6-7%, respectively, the explosion power was the most.更多还原