Experimental Investigation of Silicon Dust Explosions in Pipes

Abstract

This thesis presents an experimental study of silicon dust explosions in different pipe configurations. The experimental configuration involved a 32-litre explosion vessel connected to pipes of different dimensions, specifically with inner diameters of 245, 157, and 62 mm and lengths ranging from 6 to 24 metres. The pipes could be connected by concentric crossovers, allowing for flexibility in the configurations. Most of the experiments were conducted with two silicon dusts of different particle size distributions. Dust explosion parameters were decided in a 20-litre USBM explosion vessel. The initial tests performed in single pipes gave rise to higher pressures when reducing the diameter of the pipe. Introducing crossovers to the configuration led to a significant increase in measured pressures. In the final configuration consisting of all pipes connected with gradually reducing the diameter, explosion pressures above 50 barg and shockwave velocities over 2000 m/s were observed. The significant pressures coupled with the shock velocities indicate that the propagation mechanism might be in the quasi-detonation regime or fast turbulent deflagration. The observed pressure can be attributed to multiple contributing factors, such as compression caused by choked flow, flame acceleration resulting from flame stretching due to increased turbulence and shock interaction, and the influence of reducing diameters that intensify these effects. The presence of crossovers has been observed to enhance pre-compression, resulting in significantly higher pressures and faster pressure development.