摘要
为准确掌握煤矿井下采空区瓦斯分布及流动规律,自主研制了常压块煤瓦斯解吸测定装置,开展了不同尺寸块煤瓦斯长时间解吸试验,分析了块煤尺寸对瓦斯解吸量、解吸速率的影响,建立了不同涌出源的采空区瓦斯涌出强度模型,并利用COMSOL Multiphysics数值模拟软件模拟分析了U形回风条件下不同涌出强度对采空区瓦斯流动的影响。结果表明,1)不同尺寸块煤(3 cm、5 cm、8 cm、13 cm)的累计瓦斯解吸量随时间延长均呈现增大趋势,在前期变化较为明显,随着时间的推移,瓦斯解吸量逐渐趋于稳定,且累计瓦斯解吸量随块煤尺寸增大呈现增长趋势;不同尺寸块煤解吸速率与时间存在负指数函数关系,且块煤尺寸越小,其初始瓦斯解吸速率与解吸速率衰减系数的平均值(试验前40d)也越大。2)在U形回风条件下,不同涌出强度模型将导致采空区瓦斯体积分数随时间呈现不同的变化趋势,采用瓦斯涌出衰减模型时,瓦斯体积分数随时间推移呈先增大后减小的变化趋势;采用均匀恒定模型时,瓦斯体积分数随时间推移先增大后趋于平缓。因此,为准确预测采空区瓦斯分布特征,制定合理高效的抽采方案,应充分考虑瓦斯涌出强度的影响。
The present paper has developed and proposed a desorption measuring device for the atmospheric pressure coal-block independently so as to control the distribution and gas flow regularity of the coal mine goaf accurately. At the same time,we have also analyzed the effects of coal-block size on the gas desorption and desorption rate. And,as a result,we have succeeded in establishing the gas emission intensity models of the goaf with different emission sources. Besides,we have also simulated the effect of the different gas emission intensity models on the gas flowing regularity in the goaf under the U-shaped return air condition by means of the COMSOL Multiphysics numerical simulation software. The results of the above development and research practice demonstrate that:(1) The cumulative gas desorption of different sizes of coal(3 cm,5 cm,8 cm,13 cm) tends to increase with time,and the early change of the cumulative gas desorption ought to be more obvious. However,such gas desorption tends to be gradually stabilized with the time going on,which indicates an increasing trend with the increase of the coalblock size. The desorption rate of the different coalblock sizes(3 cm,5 cm,8 cm,13 cm) is inclined to have a negative exponential function related with the time going on. For example,the smaller the attenuation coefficient of the coal size is,and,the greater the average desorption rate of the initial gas,the greater desorption rate(for the first 40 days of the test) would be;(2) Under the U-shaped return air condition,the different gas emission intensities caused by the gas volume fraction also demonstrate different trends with the time. When the gas emission attenuation model were to be adopted,the gas volume fraction may tend to increase first and then decrease with the time going on. But,in contrast,if a uniform constant model is taken,the gas volume fraction would increase first with the time going on and then tends to get milder. Therefore,in order to accurately predict the gas distribution features of the goaf,it ought to develop a reasonable and efficient extraction schedule or plan,in which the impact of gas emission intensity has to be taken into full account.
作者
戴林超
曹偈
赵旭生
王然
DAI Lin-chao;CAO Jie;ZHAO Xu-sheng;WANG Ran(China Coal Technology Engineering Group Chongqing Research Institute,State Key Laboratory of the Gas Disaster Detecting Preventing and Emergency Controlling,Chongqing 400037,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2019年第6期1963-1970,共8页
Journal of Safety and Environment
基金
国家自然科学基金面上项目(51774319)
天地科技股份有限公司科技创新创业资金专项青年项目(2019-TD-QN040)
关键词
安全工程
采空区瓦斯
块煤解吸
涌出强度
流动规律
safety engineering
gas in goaf
desorption of block coal
effusion intensity
flow law
