基于煤与瓦斯共采的无风掘进瓦斯与氧气阻隔机理研究

发布时间：2018-08-06 09:31

【摘要】：煤矿生产中瓦斯灾害严重.目前的防治理论与技术尚未完全根除瓦斯事故,瓦斯超限及爆炸现象时有发生。本文基于周世宁院士提出的高瓦斯煤层密闭空间煤与瓦斯共采的理论,构建了集中巷通风、掘进巷不通风的新型无风掘进系统模型,分析了无风掘进的巷道布置、煤料运输、人员安全及舒适性保障、瓦斯抽采、瓦斯与氧气阻隔等子系统,研究了无风掘进的优缺点及可行性。实现无风掘进,关键在于将瓦斯与氧气有效阻隔,为此分别对瓦斯和氧气的阻隔机理进行研究。瓦斯控制主要在于明确瓦斯空间浓度分布与涌出量、抽采量、泄漏量、氮气幕阻隔速度之间的关系。考虑工作面推进过程中煤壁及煤块瓦斯放散总时间不同这一因素,通过微元积分再求和的方式,推导出了一个作业循环中瓦斯涌出总量的表达式;建立了泄漏瓦斯输运动力学模型,得出了在涌出量、抽采量、浮力及黏性阻力等多因素影响下的瓦斯连续输运规律、动量及能量控制方程;通过菲克定律及高斯烟团模型经傅立叶变换推导出了瓦斯浓度的时空分布规律:根据射流卷吸作用,得出了氮气幕阻隔速度与瓦斯浓度的关系式。针对瓦斯输运规律,提出了风门硬阻挡-抽采动态调压-氮气幕软阻隔三者联动控制瓦斯的方法。通过相似模拟、数值分析及中澳实训现场仿真实验,研究了上述四种变量对瓦斯运移规律的影响,验证了风门开启与关闭状态下,瓦斯阻隔装置与控制方法的有效性。氧气阻隔分为风门开启与关闭两种状态进行研究。风门开启状态下氧气控制方法与瓦斯相似,预先启动氮气幕,等量驱替风门开启所扰动范围内的氧气,保证风门开启过程中涡流场内的气体为氮气:同时启动正压区内的氮气幕,利用正压法阻隔氧气进入掘进巷。风门关闭时,根据伯努利方程,推导出了阻隔氧气时各区间的气体压力关系,利用压差作用,保证只存在由氮气正压区向集中巷的单向流动,以此实现对氧气的阻隔。建立了相似模拟和数值分析模型,验证了绕道巷氧阻隔机制的有效性。上述研究表明,在无风掘进模型中,采用风门、抽采、氮气幕动态调节的方法,可以实现瓦斯和氧气的有效阻隔,为无风掘进工艺的实施提供了理论与实验依据。
[Abstract]:Gas disaster is serious in coal mine production. At present, the prevention theory and technology have not completely eliminated the gas accident, the gas overrun and the explosion phenomenon occur from time to time. Based on the theory of coal and gas mining in closed space of high gas coal seam put forward by academician Zhou Shining, this paper constructs a new type of no-wind tunneling system model for ventilation of concentrated roadway and unventilated roadway, and analyzes the layout of roadway and transportation of coal and materials without wind tunneling. The safety and comfort of personnel, gas extraction, gas and oxygen barrier subsystem, the advantages, disadvantages and feasibility of no-wind tunneling are studied. The key to achieve windless tunneling is to effectively block gas from oxygen. Therefore, the barrier mechanism of gas and oxygen is studied separately. The main purpose of gas control is to determine the relationship between gas concentration distribution and gas emission, drainage, leakage and nitrogen screen barrier velocity. Considering that the total time of coal wall and coal block gas emission is different in the process of working face advance, the expression of total gas emission in a working cycle is deduced by the way of summation of differential integral. The dynamic model of gas leakage transportation is established, and the control equations of momentum and energy are obtained under the influence of many factors, such as quantity of emission, quantity of extraction, buoyancy and viscous resistance, etc. By means of Fick's law and Gao Si smoke mass model, the temporal and spatial distribution of gas concentration is deduced by Fourier transform. According to the action of jet entrainment, the relationship between the barrier velocity of nitrogen curtain and gas concentration is obtained. According to the law of gas transportation, a method of gas control is put forward in this paper, which is combined with hard blocking, dynamic pressure regulation of draught and soft barrier of nitrogen curtain. The effects of the above four variables on the gas migration law are studied through similar simulation, numerical analysis and field simulation experiments in China and Australia. The effectiveness of the gas barrier device and control method is verified under the condition of opening and closing of the tuyere. The oxygen barrier is divided into two states: the opening and closing of the tuyere. The oxygen control method is similar to that of gas in the open state of the tuyere. The nitrogen curtain is started in advance and the oxygen in the disturbed range of the opening of the air valve is driven by the same amount. At the same time, the nitrogen curtain in the barotropic zone is started, and the barotropic method is used to block the oxygen into the drivage roadway. On the basis of Bernoulli's equation, the gas pressure relationship of every interval in blocking oxygen is deduced. The pressure difference is used to ensure that there is only one way flow from the positive pressure zone of nitrogen to the concentrated roadway, so as to achieve the barrier of oxygen. Similarity simulation and numerical analysis model were established to verify the effectiveness of oxygen barrier mechanism in bypass lane. The above research shows that the effective barrier between gas and oxygen can be realized by adopting the methods of tuyere, extraction and dynamic adjustment of nitrogen curtain in the no-wind tunneling model, which provides the theoretical and experimental basis for the implementation of the no-wind tunneling technology.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD712

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