【作者】 尚宾；

【导师】 高建良；

【作者基本信息】 河南理工大学 ， 矿业工程， 2011， 硕士

【摘要】 钻孔瓦斯涌出初速度是预测煤与瓦斯突出的关键指标之一,其大小与煤层瓦斯赋存、钻孔测量室的位置和体积、导气管的阻力特性有关。建立了瓦斯在煤层运移、向测量室涌出、测量室瓦斯压力变化、瓦斯沿导气管流出的数学模型式。利用有限差分法解算了测量室动态压力边界条件下钻孔周围煤层瓦斯流动、得到测量室瓦斯压力变化及钻孔瓦斯流量、随时间的变化规律。分析了煤层瓦斯压力、透气性系数和导管阻力对钻孔瓦斯流量及钻孔瓦斯涌出初速度的影响。结果表明：煤层瓦斯压力、透气性系数和导管阻力不同时,测定的钻孔瓦斯流量最大值出现的时间、大小不同。煤层瓦斯压力和透气性系数对钻孔瓦斯流量及钻孔瓦斯涌出初速度的影响最大。在导气管阻力特性方面,导管管径对测定值的影响最大。导气管摩擦风阻越小,钻孔瓦斯流量越大、测得的瓦斯涌出初速度越大。更多还原

【Abstract】 Initial velocity of gas emission from borehole is one of the most important indexes for the coal and gas outburst prediction. It is related to the gas storage, the position and volume of the measuring chamber, and the airway resistance. The mathematical model of gas flow in the coal seam, gas flow into the measuring chamber, gas pressure change in the measuring chamber, and gas flow out of the chamber through the airway is established. Using the finite difference method, gas flow around borehole with measuring chamber is measured under dynamic boundary conditions. The variation rule of gas pressure in the measuring chamber and the gas flow quantity in borehole with time is obtained. The influence of gas storage and airway resistance on initial velocity of gas emission from borehole is analyzed. Results show that:When airway resistance, original gas pressure and permeability coefficient is not the same, the maximum value and appear time of gas flow quantity is different. Original gas pressure and permeability coefficient has great impacts on the value of gas flow in borehole. Airway diameter has great impacts in airway resistance on the value of gas flow in borehole. When the airway resistance is smaller, the gas flow quantity is bigger, and the initial velocity of gas emission from borehole is bigger too.更多还原