Effect of heat transfer through wire core toward unburned region on the extinction of spreading flame over electric wires

Abstract

The effects of core material on the extinction characteristics of the flame spreading over electric wires have been investigated. The theoretical analysis reveals that heat loss in the unburned zone has a negative feedback mechanism for the flame spread process. The reduction of the flame spread rate increases heat loss in the unburned zone and induces the quenching extinction as a result of extended thermal diffusion length. It is also found that a highly conductive wire increases heat loss rather than poorly conductive wire even under the same flame spread rate. Lastly, applicable conditions of the model are discussed based on the correlation between the thermal boundary layer and the stand-off distance of the spreading flame.