金属粉尘爆炸的浓度预警射频方法研究

Forewarning of metal dusts explosion using radio frequency concentration measurement

设计柔性射频传感器测量爆炸下限浓度范围的金属粉尘浓度。根据被测介质浓度作用介电常数原理,通过归一化相位反演粉尘浓度。通过电磁仿真软件CST建立了球体粉尘均匀径向分布的1.2 L哈特曼管模型。仿真分析了不同粉尘粒径和粉尘数量的管道截面电磁场能量分布。结果表明,金属粉尘阻碍电磁能量在哈特曼管中的传播,能量场呈现对称分布,粒径越大、数量越多,电磁能量越低。搭建了粉尘喷扬实验系统,测量了不同浓度的传感响应。结果表明,传感器对60〜1750 g/m^3浓度粉尘具备0.2〜0.8的归一化相位分辨率,且归一化相位与粉尘浓度线性拟合的可信区间在97%以内。

A flexible radio frequency sensor was designed to measure the metal dust concentration in the lower explosion concentration range.The dust concentration can be denoted by the normalized phase according to the principle of the dielectric constant.A 1.2 L Hartmann tube was modeled using electromagnetic simulation software CST.The dust distribution was set as uniform radial distribution.The energy distribution of electromagnetic field in pipeline section was simulated with different particle sizes and different particle number.The simulation results showed that metal dust hinders the energy propagation in the Hartmann tube,and the energy field presents symmetrical distribution.Bigger particle size and particle number leads to lower electromagnetic energy.An experimental system of dust spraying was set up.The sensor responses were measured with different concentrations.The experiment results showed that the sensor has a normalized phase resolution of 0.2〜0.8 for 60〜1750 g/m^3 dust concentration.Meanwhile,the confidence interval of linear fitting between the normalized phase and dust concentration is within 97%.