煤粒瓦斯扩散及扩散系数测定方法的研究

基于理论分析建立了第三类边界条件下的煤粒瓦斯扩散方程，并给出了解析解。对解析解的分析表明，第一类边界条件下及煤粒内部浓度均匀一致条件下的扩散是第三类边界条件下的特例或近似过程。煤粒瓦斯扩散过程能否近似简化成第一类边界条件下和内部浓度均匀一致条件下的扩散过程，取决于煤粒内部扩散系数和表面扩散传质采数的相对大小，文中介绍了这两个系数的测试方法，并给出了测试实例。     

瓦斯球向流动的数学模拟

本文把瓦斯在煤粒中的流动过程看作是气体在多孔介质中的扩散运动。通过模拟和对一些矿井煤样的实际测定,验证了Fick扩散模型的适用性;运用相似理论探讨了煤粒内部的瓦斯流动状态、浓度分布规律以及球向流动场的特点。经模拟和实测结果对比,初步肯定了用扩散模型描述低破坏类型煤的瓦斯放散过程是比较理想的。     

脉动通风消除上隅角瓦斯积聚的理论分析

针对“U”型采煤工作面上隅角瓦斯积聚问题,建立了脉动通风作用下上隅角风流动力学极坐标方程及瓦斯传质方程,详细分析了脉动通风作用下上隅角瓦斯的传质运移过程,论述了瓦斯扩散传质机理,并通过现场试验验证了脉动通风解决上隅角瓦斯积聚是有效、可行的。     

考虑稳定性的乳化液膜扩散传质模型及求解

本文针对乳化液膜体系扩散传质模型的建立过程中所存在的问题，深入分析了影响学府膜性的溶胀，膜破裂等现象对传质过程所造成的影响，建立了综合反映渗透溶胀、膜破裂影响的扩散传质模型。这种数学模型与实际萃取情况更为相符，采用了有限差分法对于该复杂模型进行求解。传质模型中考虑了乳状液滴外相边界层、表面活性剂层对传质过程的阻力影响，计算结果与实验结果更为吻合，从而证明了所建模型的合理性。     

基于两种数学模型的煤粒瓦斯放散数值解算

设计了煤粒瓦斯解吸实验,得到4种粒径煤样在4组不同初始压力条件下累积解吸量随时间变化的实测曲线.根据菲克扩散定律与达西渗流定律分别建立了瓦斯在球形煤粒中放散的数学模型,通过有限差分的方法并利用VB编程进行解算,得到煤粒在不同初始压力下的累积解吸量.通过与实验结果对比,表明达西模拟结果与实验结果匹配度较高,而菲克模拟结果与之偏离较大.验证了煤粒中的瓦斯放散更符合达西定律.     

考虑稳定性的乳化液膜扩散传质模型及求解

本文针对乳化液膜体系扩散传质模型的建立过程中所存在的问题，深入分析了影响液膜稳定性的溶胀、膜破裂等现象对传质过程所造成的影响。建立了综合反映渗透溶胀、膜破裂影响的扩散件质模型、这种数学模型与实际革取情况更为相符。采用了有限差分法对于该复杂模型进行求解。传质摸型中考虑了乳状液滴外相边界层、表面活性剂层对传质过程的阻力影响。计算结果与实验结果更为吻合，从而证明了所建模型的合理性。     

气体搅拌萃取塔中轴向混合及传质性能的研究

在内径为50mm的气体搅拌萃取塔中,研究了空气－水－煤油系统的轴向混合特征,分别测定了连续相和分散相的轴向扩散系数,利用轴向扩散模型求出了传质系数,并与活塞流模型进行了比较,得到了轴向扩散模型传质系数的经验关联式。     

新垂直筛板帽罩单元传质性能研究（Ⅰ）：传质模型的建立与分析

根据帽罩单元两相流动的实际情况，在前人的传质池基础上，提出了帽罩单元传质由罩内、外传质两部分组成；导出各自的传质模型；分析了传质单元数、解吸因子及液相Ｐｅｃｌｅｔ准数对罩内传质效率的影响；分析了传质单元数对罩外传质效率的影响。     

乳状液膜提取堆浸液中Cu^2＋的络合—扩散传质过程试验研究

对乳状液膜提取铜矿堆浸液中Cu^2 的传输过程进行了讨论，建立了Lix98N作流动载体提取Cu^2 的络合－扩散传质数学模型，并对该模型进行了实验验证，结果说明络合－扩散传质模型具有一定的普遍性。     

采空区混合气运动基本方程及其有限元解法

针对采空区瓦斯与空气混合气三维非线性渗流及扩散传质问题，考虑混合气密度不均匀及重力作用下的上浮因素，建立了三维采空区内变密度混合气非线性渗流及扩散运动的基本方程组．通过数学变换，得出该方程组的相容耦合可解方程组，并用Ｇａｌｅｒｋｉｎ有限元法和上游加权技术对其求解．文末，介绍了可解方程组的相容耦合迭代求解过程和算例．     

Time-varying diffusion characteristics of different gases in coal particles

Based on the analytical solution of gas diffusion in spherical coal particles with a constant diffusion coefficient, a calculation method of time-varying diffusion coefficient is proposed by constructing objective function. The time-varying diffusion behavior of methane, nitrogen and carbon dioxide in the coal particles was studied. The results show that with the increase of diffusion time, the diffusion coefficients of methane, nitrogen and carbon dioxide gas in the coal particles exhibit an attenuation characteristic, eventually approaching a limit value individually. The diffusion coefficient of carbon dioxide is larger than methane, and the diffusion coefficient of nitrogen is smallest. Significant phenomenon of limited diffusion was observed for coal of strong adsorption capability. Through the analysis of the diffusion coefficient of gases at different diffusion time, a mathematical model describing the time-varying diffusion characteristic of gases is obtained. The implementation of mixed gases to replace coal bed methane has a very important practical significance.     

煤和瓦斯突出机理的流变假说

目前煤和瓦斯突出机理的假说,都是在弹性力学基础上建立的,缺少时间因素,难于完满地解释突出的发生发展过程。作者通过对含瓦斯煤样在三维受力状态下流变特性的研究,得出了含瓦斯煤样蠕变行为的数学模型,能够比较好地阐明突出的机理。实验表明,突出煤和非突出煤其流变行为并无本质区别,只要条件具备,各类煤层都有产生突出的可能。含瓦斯煤蠕变方程的导出为建立广义的突出危险综合指标提供了基础。     

Constitutive model for methane desorption and diffusion based on pore structure differences between soft and hard coal

This paper aims to improve the accuracy and applicability of gas diffusion mathematical models from coal particles. Firstly, a new constitutive model for gas diffusion from coal particles with tri-disperse pore structure is constructed by considering the difference in characteristics between soft coal and hard coal.The analytical solution is then derived, that is, the quantitative relationship between gas diffusion rate(Qt/Q_∞) and diffusion time(t), The pore structure parameters of soft coal and hard coal from Juji coal mine are determined. Gas diffusion rules are numerically calculated and investigated by physical simulation methods. Lastly, the applicability of this model is verified. The results show that the homogeneous model only applies to the gas diffusion process of hard coal during the initial 10 min. The calculation results from this model and the physical experimental results of soft coal and hard coal are nearly identical during the initial 30 min.     

Strength criterion effect of the translator and destabilization model of gas-bearing coal seam

Coal seam destabilization inflicts damage to equipment, causes property loss and personnel casualties,and severely threatens mining safety and efficient production. To further understand this destabilization based on the basic theory of Lippmann seam destabilization, a mathematical model was introduced for gas pressure distribution by considering intermediate principal stress and support resistance.Subsequently, we established a translation model suitable for the entire roadway coal seam with rocky roof and floor by applying the unified form of yield criterion in the state of plane strain. We also obtained the analytic expressions of coal seam stress distribution on both sides of the roadway and the widths of plastic and disturbance zones. Afterward, we analyzed several typical cases with different material yield criteria, obtained the plastic zone widths of the coal seam under different gas pressures, and assessed the effects of support resistance, roadway size, and coal strength on coal seam destabilization. Results showed that: the results obtained on the basis of Wilson and Mohr–Coulomb criteria are considerably conservative, and the use of Druker–Prager criteria to evaluate the rockburst-induced coal seam destabilization is safer than the use of the two other criteria; coal seam stability is correlated with gas pressure;and high-pressure gas accelerates the coal seam destabilization.     

再燃烧条件下煤粉热解特性的实验研究

利用携带流反应装置,研究了煤粉在高温烟气环境中热解时的质量损失和c、H、N元素释放特性,采用扫描电镜和氮吸附方法观测了煤焦的显微结构、比表面积和总孔容积．结果表明,随着煤阶的降低,其煤焦比表面积和总孔容均升高,小龙潭褐煤增加最多,六枝贫煤增加最少;随着煤粉初始挥发分含量的增加和热解烟气温度升高,煤的质量损失增加,烟气气氛对煤粉质量损失份额影响较小;在实验条件下,煤中C、N析出份额与煤的质量损失份额基本相同,H释放份额远大于C、N和煤质量损失,达80％以上．     

温湿度梯度耦合作用下室内燃气泄漏模拟研究

以非平衡统计热力学和不可逆热力学为理论依据,建立温度梯度和湿度梯度耦合情况下扩散模型,结合受限空间内燃气泄漏扩散模型,建立多因素耦合作用下燃气泄漏扩散数学模型,并运用Matlab软件对室内燃气扩散过程进行了模拟分析。通过分析得到了温度和湿度梯度对燃气泄漏扩散的影响规律以及耦合作用下对燃气泄漏扩散的影响规律。研究结果将为燃气扩散规律的研究及事故发生时人员及时安全的进行撤离提供参考。     

城市轨道交通供电系统光纤纵差保护判据仿真研究

城市轨道交通供电系统的电压等级较高、输送距离短且较多采用电力电缆进行电能的传输,本文针对光纤纵差保护原理,开发了基于PSCAD/EMTDC的故障分量相量的差动保护判据和基于故障分量采样值的差动保护判据的差动保护模块,仿真了这两种差动保护判据在广州地铁二号线电力电缆线路上应用的效果。结果表明,所建立的继电保护模块能够正确实现相应的保护原理所应实现的功能,与常规相量差动保护判据相比,本文所研究的保护判据允许接地过渡电阻的能力及灵敏性方面具有明显的优势。     

煤层瓦斯扩散与渗流规律的初步探讨

借鉴石油天然气在孔隙裂隙二重介质中的渗流理论,依据相关的实验研究,结合煤层瓦斯流动的特点,建立了煤层瓦斯扩散与渗流的物理数学模型,并分析了其特点及今后的研究方向。