基于FDTD的电磁波在煤中传播特性

发布时间：2019-03-01 15:28

【摘要】：针对矿山灾害事故发生时,逃生通道被堵,被困人员位置难以确定这一难题,以钻孔生命雷达为手段,开展了电磁波在煤矿井下传播规律的研究。采用时域有限差分法(FDTD)建立井下二维空间磁场(TM)模型,利用Gpr Max和Matlab数值软件对模型进行正演模拟计算。通过理论分析与正演模拟,研究了天线中心频率、激励源、煤质与煤温等条件改变时,反射波的幅值强度与反射系数变化规律,目标的探测时间与分辨率,揭示了电磁波在煤体中的传播规律。研究结果表明:天线中心频率为600 MHz的Ricker激励源是最佳探测方式;电磁波在烟煤中的传播速度最快,褐煤居中,无烟煤最次;电磁波在煤中的传播速度随温度的增加而增大,人体反射波幅值强度则随之减弱;人体反射波幅值强度与探测距离呈对数函数关系,据此提出建立相应数据库;确定了生命雷达与被困人员之间煤体厚度的计算方法。研究结果可为生命雷达系统的研发和现场救援探测数据的解释提供参考与支撑。
[Abstract]:In view of the difficult problem that the escape passage is blocked and the position of trapped persons is difficult to determine when a mine disaster occurs, a study on the law of electromagnetic wave propagation in coal mines is carried out by means of borehole life radar. The (TM) model of underground two-dimensional spatial magnetic field is established by using finite-difference time-domain (FDTD) method. The forward simulation of the model is carried out by using Gpr Max and Matlab numerical software. Through theoretical analysis and forward simulation, the variation rule of amplitude intensity and reflection coefficient of reflection wave, detection time and resolution of target are studied when the central frequency of antenna, excitation source, coal quality and coal temperature are changed. The propagation law of electromagnetic wave in coal is revealed. The results show that the Ricker excitation source with the antenna center frequency of 600 MHz is the best detection method, and the propagation speed of electromagnetic wave in bituminous coal is the fastest, the lignite is in the middle, and the anthracite is the second. The propagation velocity of electromagnetic wave in coal increases with the increase of temperature, and the amplitude intensity of human reflection wave decreases, and the relationship between the amplitude intensity of human reflection wave and the detection distance is logarithmic, so the corresponding database is put forward. The calculation method of coal mass thickness between life radar and trapped personnel is determined. The results can provide reference and support for the research and development of life radar system and the interpretation of field rescue detection data.
【作者单位】：西安科技大学安全科学与工程学院;西安科技大学陕西省煤火灾害防治重点实验室;国家矿山救援西安研究中心;
【基金】：国家重点研发计划资助项目(2016YFC0801800-02) 国家自然科学基金青年基金资助项目(51504186) 中国博士后基金资助项目(2016-M-592820)
【分类号】：TD65

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