燃烧管中烟煤粉粉尘云传播参数的试验研究

利用自行设计的长29.6 m,内径199 mm,配有特殊扬尘装置的大犁卧式燃烧爆炸管道试验系统,对弱点火条件下烟煤粉与空气两相悬浮流中的爆炸过程进行了试验研究,用压电传感器测量了管内各测点的压力信号,观测到快速爆燃的状态稳定,分析了爆燃波稳定传播机理.结果表明:在煤粉浓度为300g/m~3及弱点火条件下,悬浮烟煤粉粉尘云中爆燃波能够稳定传播,且稳态传播距离持续20 m以上,峰值超压和波速平均值分别约为70 kPa和430m/s.

Experimental investigation of propagation parameters through bituminous coal powder clouds hi a combustion tube

The present paper is aimed to introduce the likely causes leading to the explosion of the two-phase system, which has become a keen interest in the recent years. For our research purpose, we have prepared a self-made large horizontal combustion tube with the inside diameter of 199 mm and the length of 29.6 m. One end of the said tube was closed with the other end connected to a large dump-tank. In our research, the forty special dust dispersion system has been used to disperse the bituminous coal dust into the experimental tube. While a uniform suspension of bituminous coal dust was produced in the tube with a diameter ranging from 46μm to 70 μm, we carried out an experimental research on the entire propagation process of deflagration waves in two-phase, suspended bituminous coal powder-air flow in the above-mentioned apparatus, with the bituminous coal dust-air mixture initiated under the weak ignition condition of 40 J electric spark. Furthermore, it is possible to develop considerable pressure along the tube with the coal dust concentration of 300 g/m~3 monitored by piezoelectric transducers. At this moment, we can find out stable deflagration waves in the coal dust-air mixture and the propagation mechanism for the stable heterogeneous dust deflagrations in air. The experimental results show that the stable propagation of the self-sustained deflagration wave can be done through the suspended bituminous coal dust clouds under the weak ignition condition with the propagation distance of the stable deflagration observed beyond 20 m. However, while the self-sustained deflagration wave propagated regularly, the mean peak overpressure and mean propagation velocity along the combustion tube tend to reach approximately 70 kPa and 430 m/s, respectively.