九道岭矿综放采空区防灭火数值模拟研究

发布时间：2018-05-04 21:37

本文选题：“O”型圈 + 多孔介质　；参考：《辽宁工程技术大学》2013年硕士论文

【摘要】：本论文结合辽宁九道岭煤业有限公司(九道岭矿)-825综放面采空区自燃防治实际问题,运用CFD数值仿真技术开展研究。采空区模型根据九道岭矿工作面的实际尺寸,用Gambit构建了有倾斜角度的3D综放采空区模型；采空区岩石冒落是非均匀的,冒落碎胀系数及孔隙度分布按“O”型圈分布的模型建立；粘性阻力系数和惯性阻力系数的计算是根据非线性渗流方程推导出来的经验公式来确定。多孔介质模块用自定义函数UDF来实现,考虑重力因素。结合九道岭矿实际防灭火工作,对常温40℃注氮、中温20℃注氮、低温-20℃注氮、上行风、下行风、中部注泡沫墙注氮和不注氮情况、进风半侧注泡沫墙注氮和不注氮情况、低温-20℃注氮气下行风在进风半侧注泡沫墙模型10种情况进行了Fluent数值模拟,得到10种不同分布条件下风压等值面线图、气体浓度分布图,并通过常温和低温注氮对比、上行风和下行风对比、中部泡沫墙和进风半侧泡沫墙分别在不注氮和注氮情况的对比,得到防火最优方案。 (1)通过常温注氮和低温注氮的模拟,得出低温注氮时采空区底板附近氮浓度较高,氧浓度高于10%区域回缩约100m；(2)通过上行通风和下行通风的对比结果显示,采用下行通风可以在很大程度上控制工作面向采空区的漏风量,比上行通风漏风量减少约80m3/min,下行风的自燃氧化带氧浓度高于16%的区域比上行风窄60m,对防治煤自燃更有利。(3)常低温注氮和上行风(即不注氮气情况)的模拟结果对比,通过计算漏风量得出注氮可以减少漏风约20m3,而低温注氮比高温注氮控制漏风效果更明显。(4)中部注泡沫墙和进风半侧注泡沫墙分别在注氮和不注氮情况下的模拟结果对比充分说明泡沫墙具有挡板作用,能阻止一部分漏风,在此基础上注氮可进一步减少漏风量。采用进风半侧注泡沫墙耗氧层氧浓度高于10%的区域比中部注泡沫墙的要小约10倍。从而得出,九道岭矿采用低温注氮、下行风、进风半侧泡沫墙三种模型都有利于控制漏风量,减少的采空区供氧,缩短遗留煤耗氧层中自燃氧化带的宽度,进而通过建立同时满足低温注氮、下行风、进风半侧泡沫墙三个条件的模型并进行Fluent模拟,模拟结果验证了推断的正确性。
[Abstract]:In this paper, combined with the actual problems of spontaneous combustion prevention and control in the goaf of the -825 fully mechanized caving face of the nine Dao Ling Coal Co., Ltd. (nine Dao Ling coal mine), the study is carried out by the CFD numerical simulation technology. The goaf model is based on the actual size of the working face of the nine mountain range, and uses Gambit to build a 3D fully mechanized caving and mining area model with the inclined angle, and the rock caving in the goaf is inhomogeneous. The coefficient and porosity distribution of the caving bulge and the porosity are established according to the "O" type ring distribution model. The calculation of the viscous drag coefficient and the inertia resistance coefficient is determined by the empirical formula derived from the nonlinear seepage equation. The porous medium module is realized by the custom function UDF, considering the gravity factor.
Combined with the actual fire prevention and extinguishing work of nine mountain range mine, nitrogen injection at 40 C at normal temperature, nitrogen injection at medium temperature 20 C, nitrogen injection at low temperature -20 C, upward wind, downward wind, nitrogen injection and nitrogen injection in the middle injection foam wall, nitrogen injection and nitrogen injection in the half side injection foam wall, and 10 cases of Fluent injection foam wall model in the semi side of the air inlet at low temperature. In the numerical simulation, the air pressure contour map and gas concentration distribution diagram under 10 different distribution conditions are obtained, and the comparison between the upper and lower winds is compared through the contrast between the normal temperature and the low temperature nitrogen injection, the middle foam wall and the air inlet half foam wall are compared with the nitrogen and nitrogen injection conditions respectively, and the best fire prevention scheme is obtained.
(1) through the simulation of nitrogen injection at normal temperature and low temperature nitrogen injection, it is found that the nitrogen concentration near the bottom floor of the goaf is higher and the oxygen concentration is higher than the 10% region 100m. (2) through the comparison between the uplink ventilation and the downlink ventilation, the downward ventilation can be used to control the air leakage for the goaf to a great extent, compared with the upward ventilation. The air leakage is reduced by about 80m3/min, and the oxygen concentration in the spontaneous combustion oxidation zone of the downwind is narrower than that of the upper wind 60m and is more favorable for preventing the spontaneous combustion of coal. (3) the comparison of the simulation results of the constant low temperature nitrogen injection and upper wind (i.e., no nitrogen injection) shows that nitrogen injection can reduce the air leakage of about 20m3 by calculating the air leakage, and the low temperature nitrogen injection is controlled by the high temperature nitrogen injection. The effect of air leakage is more obvious. (4) the comparison of the simulation results in the middle injection foam wall and the half side injection foam wall under the condition of nitrogen injection and nitrogen injection shows that the foam wall has the effect of baffle and can prevent a part of air leakage. On this basis, the nitrogen injection can further reduce the air leakage. The oxygen concentration in the oxygen injection wall of the half side injection foam wall of the inlet is higher than 10%. The region is about 10 times smaller than that in the middle part of the foam wall. Thus, it is concluded that the three models of nine mountain mines using low temperature nitrogen injection, downward wind and half side foam wall are all beneficial to control the air leakage, reduce the oxygen supply in the goaf, shorten the width of the spontaneous combustion oxidation zone in the oxygen layer of the coal consumption, and enter the same time to meet the low temperature injection, downwind, and air intake. The three conditions of the half wall foam wall are simulated by Fluent, and the simulation results verify the correctness of the inference.

【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TD753

【参考文献】