• 论文
主办单位:煤炭科学研究总院有限公司、中国煤炭学会学术期刊工作委员会
等离子体对煤体选择性破碎的实验与数值模拟分析
  • Title

    Experiment and simulation of selective cracking of coal samples by plasma

  • 作者

    林柏泉张祥良李彦君朱传杰

  • Author

    LIN Baiquan,ZHANG Xiangliang,LI Yanjun,ZHU Chuanjie

  • 单位

    中国矿业大学 煤矿瓦斯与火灾防治教育部重点实验室中国矿业大学 安全工程学院

  • Organization
    1. Key Laboratory of Coal Methane and Fire Control,Ministry of Education,China University of Mining and Technology,Xuzhou  221116,China; 2. School of Safety Engineering,China University of Mining and Technology,Xuzhou  221116,China
  • 摘要

    为了研究等离子体冲击作用下煤体内部的裂隙扩展规律,利用自主搭建的等离子体冲击实验平台,并通过实验和数值模拟相结合的方法对等离子体冲击作用下煤体的破碎规律进行了研究。实验中以等离子体破碎的煤体为对象,并结合三维可视化软件Dragonfly提取了红柳烟煤在等离子体作用下的裂隙相、矿物相,深入分析了等离子体冲击后煤体内部裂隙沿着不同方向的扩展规律。并以数值模拟软件Comsol Multiphysics为基础分析了等离子体冲击作用下含矿物煤体内部的电场强度分布规律。实验结果表明,等离子体冲击作用下在煤体内部形成相互贯通的空间裂隙网络,且裂纹呈现出由电极中心向四周发散的状态,在靠近电极的两端破碎效果较好,表明煤体的破碎效果与电场的集中程度正相关,电场越集中,能量越大,破碎效果越好。此外,裂隙在轴向和平面上均具有沿着矿物分布的特征,说明在等离子体作用下矿物与煤体分界面处产生了电场的畸变,引发了应力的集中,矿物的分布对裂隙存在着诱导作用。通过数值模拟验证了煤体中矿物和孔隙的存在对电场存在的影响规律,结果表明电场强度会在介电常数不同的介质中发生畸变,当电场穿过高介电常数的介质时会在介质内部形成较低的场强,当电场穿过低介电常数的介质时会在介质内部形成较高的场强。数值模拟得到的电场畸变的结果是对实验结果补充说明,实验所得到的结论是数值模拟宏观结果的体现与验证。

  • Abstract
    The plasma crushing technology has been widely used in many fields,and some related researches show that it has a good application prospect in the field of coal fracturing. In order to investigate the law of crack propagation in coal treated by plasma technology,the law of coal breakage under the impact of plasma was studied through a self-de- signed plasma test platform by means of experiment and numerical simulation. In the experiment,with the coal crushed by plasma being the research object,the fracture and mineral phases in Hongliu bituminous coal were extracted ac- cording to different thresholds with the aid of the three-dimensional visualization software Dragonfly. Meanwhile,the law of crack propagation along different directions was analyzed in depth. Furthermore,based on the numerical simula- tion software Comsol Mul-tiphysics,the distribution of electric field intensity in mineral-bearing coal under plasma impact was analyzed. The results show that an interconnected fracture network is formed in the coal under the impact of plasma,and the cracks diverge from the electrode center to all sides. The breaking effect is better at both ends near the electrode,indicating that the breaking effect of the coal is positively correlated with the concentration of electric field. The more concentrated the electric field is,the greater the energy is,and the better the breaking effect is. Besides,the fractures distribute along minerals in both the axial direction and the plane,revealing that the electrical field distorts at the interface between minerals and fractures. The distribution of minerals induces the initiation of fractures. The influ- ence of mineral and pore in coal on the electrical field was verified through numerical simulation. The results suggest that the electrical field intensity will distort in dielectrics with different dielectric constants. Lower field intensity will be formed inside the dielectric when the electrical field passes through the dielectric with a high dielectric constant, whereas higher field intensity will be formed inside the dielectric when the electrical field passes through the dielectric with a low dielectric constant. The numerical simulation results are a supplementary explanation to the experimental re- sults,and the experimental results are the embodiment and validation of the macroscopic results of numerical simula- tion.
  • 关键词

    等离子体选择性破碎介电常数电场畸变裂隙

  • KeyWords

    plasma;selective fragmentation;dielectric constant;electrical field distortion;fracture

  • 基金项目(Foundation)
    国家自然科学基金资助项目(51474211);国家重点研发计划资助项目(2016YFC0801402)
  • DOI
  • Citation
    LIN Baiquan,ZHANG Xiangliang,LI Yanjun,et al. Experiment and simulation of selective cracking of coal samples by plasma[J]. Journal of China Coal Society,2019,44(11):3472-3479.
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