煤矿井下电磁波安全性研究

本申请书应对2012年度国家自然科学基金煤炭联合基金项目指南中的“煤矿井下电磁波安全性”的项目计划。无线通信设备在煤矿井下爆炸性气体环境中使用，有两类因素会引起瓦斯爆炸：设备自身电气安全和电磁波辐射能量安全，本项目研究后者对瓦斯气体的安全性，重点关注射频系统感应到金属结构上的能量，在刮擦短路等极端情况下产生放电火花的安全性。本项目将通过电磁波能量放电点火门限功率实验，得到电磁波频率与瓦斯气体点火门限功率之间的关系。研究矿井电磁波远场传播特性，建立三段式电磁波传播模型，研究煤矿井下电磁波近场耦合特性。对矿用典型设备和金属结构进行分类，从等效天线的角度研究井下电磁波与金属结构的能量耦合。分别研究电磁波与金属结构谐振时获取的最大功率，和多发射机情况下电磁波与金属结构失谐时获取的最大功率,并与点燃门限对比，以确定电磁波辐射感应能量的安全性。提出煤矿井下电磁波安全性评价方法。

This application deals with the subject of the safety of electromagnetic wave in the underground coal mine, which can be found in the project guide of 2012 National Natural Science Foundation of China-- Coal United Fund. When wireless communication equipments are used in coal mine explosive gas atmosphere, there are two types of factors which may cause gas explosion. They are electrical safety of the equipments and the safety of electromagnetic wave energy. This project mainly researches the safety of electromagnetic energy for gas in coal mine. It focuses on the energy which radio frequency devices induct with the metal structures, and it mainly considers the safety of discharge spark produced in extreme cases, such as scraping and short circuit. This project will conduct the experiment which can determine the threshold power of the electromagnetic energy discharge spark ignition, and find the relation between the threshold power and the electromagnetic wave frequency. Then, this project researches the propagation characteristics of electromagnetic wave in coal mine, and sets the models of electromagnetic wave for far field propagation and researches the characteristics of near field coupling energy in coal mine. Classify the mine typical equipments and metal structures and research energy coupling characteristics between electromagnetic wave and metal structures from the view of equivalent antenna. This project then researches the maximum power which the load can obtain, when the structures are resonant with the electromagnetic wave, and the maximum power when the structures are non-resonant with the electromagnetic wave. The calculated maximum power then should be used to compare with the threshold power of the electromagnetic energy discharge spark ignition to determine the safety of electromagnetic wave in coal mine. Finally, this project proposes the assessment method of the safety of electromagnetic wave in coal mine.