煤矿火区封闭对火区内气体运移规律影响研究

发布时间：2018-06-02 17:03

本文选题：矿井火灾 + 火区封闭　；参考：《湖南科技大学》2014年硕士论文

【摘要】：煤矿火灾是严重危害煤炭安全生产的五大灾害之一，其具有突发、火势迅猛和救灾困难等特点。当矿井发生的火灾直接灭火困难使火灾持续了2小时以上时，为了控制火势的发展，便需要对发生火灾的区域两端进行封闭，然后向火区内注入惰性气体、灌浆、注水等进行灭火。但在进行封闭的过程中或封闭后，由于风流紊乱等原因火区内可能会发生瓦斯爆炸，使火灾救灾的效果未能达到。对火区的封闭有“先进后回”、“先回后进”和同时封闭三种顺序。不同封闭顺序下机械风压、火风压等影响火区内风流流动的因素也在发生着不同的变化。本文以煤矿火灾的燃烧特征、烟流流动等理论为基础，根据火灾燃烧过程中可能发生的物理化学反应和井巷特点，分析了火区中气体和烟流的来源和成分；并以氧气为例，通过公式推导描述了火区内气体浓度变化的特点。分别运用公式对正常通风条件下和火区封闭后火区内烟气层的运移和可燃气体层的浓度分布进行了描述；列出瓦斯涌出和运移的五种形式和火灾时期火区可能出现的四种风流紊乱形式，并分别对其特点进行了描述。分析了封闭顺序对火区气体运移的影响，研究了机械风压与火风压的耦合作用，并通过公式推导分析了火区风压的改变对火区内气体运移的影响。运用Gambit建立了发生火灾巷道的三维物理模型，并对火灾流场模型进行了恰当的设定，对控制火区气体流动的方程组进行了描述；并选定了火灾模拟的湍流模型等，拟定了对火区封闭数值模拟的边界条件和初始条件。然后运用Fluent软件对不同封闭顺序下巷道封闭火区内气体运移进行了三维数值模拟。根据模拟结果，分析了不同封闭顺序封闭过程中和完成后火区内气体的运移规律。并通过分析不同条件下火区内的温度、瓦斯浓度和氧气浓度,得到火区内发生瓦斯爆炸的危险性，从而讨论各种封闭顺序的安全性。根据分析结果，，对封闭顺序的选择、防火墙的构建及布置和火区的管理等措施提出了一些建议。最终为火区封闭顺序的选择提供了理论基础，提高火灾救灾的安全性。
[Abstract]:Coal mine fire is one of the five major disasters which seriously endangering the safety of coal production. It has the characteristics of sudden, rapid fire and disaster relief. When the fire is difficult to fire for more than 2 hours, the fire disaster should be closed to the two ends of the fire disaster and then inject into the fire area. Inert gas, grouting, water injection and so on are used to extinguish the fire. However, gas explosion may occur in the fire area due to the disturbance of wind and flow in the closed process. The effect of the fire disaster relief can not be reached.
The closure of the fire area has "advanced back back", "back and forth" and closed three order. The factors that affect the flow of wind flow in the fire area under the different closure order, such as mechanical wind pressure and Huo Feng pressure, are also different. This paper is based on the theory of the combustion characteristics of the coal mine and the flow of smoke flow and so on, according to the fire combustion process. The source and composition of the gas and the smoke flow in the fire area are analyzed, and the characteristics of the gas concentration change in the fire area are described by the formula derivation.
The movement of the smoke layer and the concentration distribution of the combustible gas layer in the closed fire zone under normal ventilation and fire area are described respectively. Five forms of gas emission and migration and four kinds of possible forms of wind turbulence may appear in fire zone in fire period are listed, and their characteristics are described respectively. The closure sequence is analyzed. In the influence of gas migration in the fire area, the coupling effect of mechanical wind pressure and Huo Feng pressure is studied, and the influence of the change of wind pressure on the gas migration in the fire area is analyzed by formula deduction.
The three-dimensional physical model of fire roadway was established by Gambit, and the fire flow field model was set properly. The equations for controlling the gas flow in the fire area were described. The turbulent model of the fire simulation was selected and the boundary conditions and initial conditions for the closed numerical simulation of the fire area were drawn up. Then the soft Fluent was used. Three dimensional numerical simulation of gas migration in closed fire area under different closed sequence was carried out. According to the simulation results, the gas movement in the closed sequence closed process and after the completion of the fire area was analyzed. By analyzing the temperature, gas concentration and oxygen concentration in the fire area under different conditions, the gas explosion occurred in the fire area. The safety of all kinds of closed order is discussed. According to the results of the analysis, some suggestions are put forward for the selection of closed sequence, the construction and arrangement of firewalls and the management of fire area. Finally, the theoretical basis is provided for the selection of the closed sequence of fire area, and the safety of the fire disaster relief is improved.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TD75

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