高温矿井制冷降温影响风流稳定性的机理研究

Heat hazard in the high temperature coal mine is one of the major threaten to the safety and efficiency of exploitation. In order to alleviate the heat damage, it is very common to use refrigeration system in the mines. When a refrigeration system is running to cool down the underground environment, the flow stability is affected by the dynamics effects caused by the mass and forced heat transfer between cooling source and air in the mine and it brings a new threat to exploit safely. In order to understand this question, the main context includes: to study the couple mechanism laws between the refrigeration and ventilation system in the mine, and to discover the influence caused by refrigerating system to air temperature and wind pressure, and stability of ventilation system, and to get the rules how air current vary in the working section when cooling system is running, and to reveal local fluctuating accumulation of methane in the upper corner of working face induced by cooling air and so on. The methods include theoretical analysis, numerical simulation, site test and experimental. The project wants to discover change and transportation of thermal and mass when mine cooling technology has been taken, and find impact mechanism of thermal exchange and coal combustion left in condition of fluctuating wind. The research result from this project will provide some solutions to air stability in case of refrigeration, and develop ventilation theory, and be good for preventing mine heat harm. There are much more benefits and broad prospects in this study.

高温矿井的热害是矿井安全高效开采的重大灾害之一，解决热害问题，往往采用制冷降温方法。矿井制冷降温时，冷源与矿井空气要进行强制性的热质交换，产生动力学效应，影响矿井风流的稳定性，威胁矿井安全生产。本项目针对此问题，采用理论分析、数值模拟、现场测试及实验研究的方法，以高温矿井为研究对象，主要研究：制冷降温系统与通风系统的耦合作用机理；制冷降温系统对矿井风温、风压及其稳定性的影响规律；制冷降温时所引起的风流在工作面处的叠加、传递及衰减规律；制冷降温引起的风流脉动对上隅角瓦斯积聚影响的局部脉动效应,等等。揭示制冷降温时高温矿井内空气的热、质变化机理及传递规律；探寻脉动风流作用下采空区空气与煤体之间的换热及对采空区遗媒自燃的影响机理及规律。本课题的研究成果将为解决高温矿井制冷降温时矿井风流稳定性问题提供依据，拓宽了矿井通风理论，对矿井热害防治很有现实意义，有较高的研究价值和广泛的应用前景。

建立了风流不稳定对制冷降温系统换热性能的影响规律计算模型，并提出了计算的边界条件；对南方煤矿井下降温系统进行了全面考察和测试，掌握了矿井降温系统运行时矿井风流参数变化的基础数据；研究了巷道壁面的传热、传湿特性，结果显示：大部分高温矿井的热源主要来自地温；分析了传热传质对巷道通风阻力的影响机理，证明其存在的条件，并提出了传质阻力概念，研究了不同传热传质强度下通风阻力的变化规律，得出：当巷道风流速度低于1m/s时传热传质对巷道阻力的影响在15%以上，当风速增大到2m/s以后传热传质对巷道的阻力约增大5%左右，传质与传热同时存在时传质会削弱热阻力，其综合效果不是简单的代数相加，传热与传质对阻力的影响是同一数量级；分析不同种类的热源产生的热力风压和风流流动热阻力对风流稳定性的影响，得到了非水平巷道热力风压影响风流方向的判别式，水平巷道热阻嵌入串、并、角联风路的风流流动规律，以及热阻嵌入风量修正的公式。通过实例分析，以通风网络解算方法得出热阻对分风风量的影响达11.8%，若在深部开采且复杂的通风网络煤矿中，热阻不仅会影响网络分风风量，严重时甚至可以引起反风,从而引起采空区遗煤自燃。提出了采用隔热分流排热降温方法，分析了隔热分流排热降温技术的关键因素，得出：采用隔热分流排热降温方法可大大提高高温掘进工作面热害防治的综合效果；利用制冷对高温高湿矿井进行降温时，在巷道中容易产生雾霾，建立了气溶胶颗粒凝并、冷凝和成核动力学模型以及破碎、蒸发和沉积动力学模型，并对雾霾形成、发展及消散过程颗粒粒径分布随时间、环境参数的演变进行研究，得出了雾霾气溶胶颗粒物运动特性及发展变化规律；完成了高温矿井降温冷负荷计算软件的编写，该软件成功的把热、湿阻力纳入了风网解算软件。