U型通风采空区气体微流动场模拟研究

发布时间：2018-04-06 04:04

本文选题：采空区　切入点：气体微流动　出处：《湖南科技大学》2017年硕士论文

【摘要】：本文以多孔介质流体动力学、高等渗流力学以及计算流体动力学为基础,针对采区通风动态特性与U形通风采空区气体微流动耦合的基础问题展开研究。本文采用相似模拟和数值模拟相结合的方法对采空区微流动场进行了研究。利用相似模拟材料进行了多孔介质流动实验,获取了陶粒填充在不同口径方管中的气体流动特性,为采空区流场实验提供了理论基础。利用采空区相似模拟实验台进行了采空区流场实验,结果表明:(1)示踪气体的流动规律是由工作面流向进风侧采空区,再由进风侧采空区流向回风侧采空区深部,最终在回风侧采空区深部聚集;(2)进风侧风流的射流惯性会使示踪气体在该侧采空区深部聚集,回风侧风流会对示踪气体存在一个卷吸作用,使回风侧采空区的示踪气体浓度较低。基于采空区流场实验台的原型建立了尺寸相同的物理模型,并利用fluent软件进行了数值模拟计算,得到了采空区示踪气体浓度分布图、采空区气体速度分布图、采空区静压分布图,结果表明:数值模拟中示踪气体浓度分布与采空区流场实验中示踪气体浓度分布规律基本保持一致,有效验证了相似模拟实验的准确性。为了研究工作面两端压差对采空区气体微流动的影响,基于相似模拟实验的数学模型,以实际采空区为研究对象,建立采空区物理模型,利用fluent软件进行了不同工作面压差下采空区气体微流动场的数值模拟计算,得到了采空区静压分布图、漏风流线图、漏风速度分布图、瓦斯浓度分布图、氧气浓度分布图,分析了工作面压差对采空区微流动场、采空区自燃“三带”、采空区瓦斯危险区域以及采空区氧气浓度场的影响。
[Abstract]:Based on the fluid dynamics of porous media, advanced seepage mechanics and computational fluid dynamics, the basic problems of coupling between the dynamic characteristics of ventilation in mining area and the micro-flow of gas in U-shaped ventilation goaf are studied in this paper.In this paper, similarity simulation and numerical simulation are used to study the microflow field in goaf.The gas flow characteristics of ceramsite filled in different diameter square tubes were obtained by using similar simulated materials in porous media, which provided a theoretical basis for the flow field experiment in goaf.The flow field experiment of goaf is carried out by using the similar test bench of goaf. The results show that the flow rule of tracer gas is from the face to the goaf on the inlet side and from the goaf on the inlet side to the deep part of the goaf on the return side.Finally, the jet inertia of the air flow on the inlet side of the goaf will cause the tracer gas to accumulate in the deep part of the goaf, and the wind flow on the return wind side will have a entrainment effect on the tracer gas.The tracer gas concentration in goaf on the return wind side is lower.Based on the prototype of the goaf flow field experiment bench, a physical model of the same size is established, and the numerical simulation calculation is carried out by using fluent software. The distribution of tracer gas concentration and the gas velocity distribution in the goaf are obtained.The results show that the distribution of tracer gas concentration in the numerical simulation is basically consistent with the distribution of tracer gas concentration in the goaf flow field experiment, which effectively verifies the accuracy of the similar simulation experiment.In order to study the effect of pressure difference between two ends of working face on gas microflow in goaf, based on the mathematical model of similar simulation experiment, the physical model of goaf is established by taking the actual goaf as the research object.The numerical simulation of gas microflow field in goaf under different working face pressure difference is carried out by using fluent software. The static pressure distribution map, leakage air flow diagram, air leakage velocity distribution, gas concentration distribution and oxygen concentration distribution in goaf are obtained.The influence of the pressure difference on the micro-flow field in goaf, the "three zones" of spontaneous combustion in goaf, the gas dangerous area in goaf and the oxygen concentration field in goaf are analyzed.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD72

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