Flame propagation of a zirconium dust cloud in a Hartmann tube

In this paper the flame propagation of a zirconium dust clouds in air is studied experimentally. The measurements were conducted in a Hartmann tube, and a high-speed CMOS camera was used to record the images of the flame. The influences of the ignition delay time, as well as the ignition energy and ignition source position are investigated. The results show that the flame speed considerably depends on both the delay time and the ignition energy. However, it is also observed that flame speed is strongly dependent on the dust concentration. Furthermore, in all cases investigated, the upward propagation is much faster than that of the downward propagation. Additionally, it is found that the flame propagation speed decreases when the ignition source is placed near the top end of the tube.status: accepte