Dripping behavior effects on flame propagation along electrical wires under high currents

Abstract

The molten dripping behavior induced by flame spread over electrical wires under different currents (0–50 A) were experimentally investigated to better understand the fire characteristics under high currents. The influence of dripping behavior on flame height and flame propagation along the wire was analyzed. The results show that the dripping behavior will cause the flame height to change periodically, but it has limited effects on the flame spread rate. The special dripping behavior (flame-fall) caused by the burning of wires under extremely high current and the pulsation phenomenon similar to liquid fire appearing in the flame propagation were firstly observed. Based on the theoretical analysis of the dripping process, a prediction model of the dripping frequency is proposed and its accuracy is verified by experimental data. Finally, by comparing the dripping cycles of the two wires used in the experiment, two control modes for dripping behavior under high current were obtained: the flame heat convection control mode and the Joule heat control mode.