| 激光辐照煤岩的热效应数值模拟分析 |
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| 引用本文： | 杨明军,王玉丹,文国军,刘浩杰,吴玲玲.激光辐照煤岩的热效应数值模拟分析[J].煤田地质与勘探,2018,46(6):217-222. |
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| 作者姓名： | 杨明军 王玉丹 文国军 刘浩杰 吴玲玲 |
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| 基金项目： | 国家自然科学基金项目（41672155）；湖北省自然科学基金杰出青年基金项目（2018CFA092） |
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| 摘 要： | 探究激光辐照煤岩的热效应，有助于理解激光作用于煤岩的成孔机制，从而为激光应用于煤层气水平钻进提供理论支持。基于传热学理论，建立了激光辐照煤岩的数学模型，通过多物理场仿真分析软件COMSOL Multiphysics对激光破岩过程中温度场分布情况进行数值计算，探讨了激光光束辐照在煤岩表面时激光功率、光斑半径及辐照时间等因素对激光作用于岩石的热效应影响。再考虑到煤岩在极高的升温速度下将发生相变，建立了其发生气体相变的数值仿真模型，对其气化后形成的烧灼孔进行模拟仿真。仿真结果分析表明，影响钻孔深度的主要因素是激光功率和辐照时间，影响孔口直径大小的主要因素是光斑直径，激光辐照煤岩的成孔机理主要是激光高温烧蚀成孔，如果用于实际钻进过程中将大幅减少固体岩屑，有助于降低排屑工艺的难度。
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| 关 键 词： | 激光辐照 煤岩 热效应 温度场 激光钻进 |
| 收稿时间： | 2017-10-31 |
Numerical simulation of thermal effects of laser irradiation on coal and rock |
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| Abstract: | To study the thermal effect of laser on coal and rock will benefit to understand the hole-forming mechanism of laser acting on coal and rock, so as to provide theoretical basis for the application of laser in CBM horizontal drilling. Based on heat transfer theory, the mathematical model of laser drilling of coal and rock by uniform light beam was established to simulate the transient temperature distribution in rocks exposed to a laser beam by COMSOL Multiphysics software. The influences of laser power, laser spot radius and irradiation time on the thermal effects were analyzed. The evaporation of coal rock at high temperature was numerically simulated, and the hole shape formed after gasification was obtained. The simulation results show that the main factors affecting the drilling depth are the laser power and radiation time, and the main factor affecting the diameter of the hole is the spot diameter. The main thermal effect of laser interaction with coal and rock is laser ablation. Once the laser is applied for methane directional well, it will decrease dramatically the solid debris, thus reducing the difficulty of debris removal during drilling. |
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