Abstract
The effect of a direct current (DC) electric field on the characteristics of flame spread over polyethylene (PE) -insulated twin electrical wires was studied by varying wire gap (S) and voltage (V-DC). The flame spread rate (FSR) for the wire with negative voltage (SF-) was larger than with positive voltage (SF+) initially and becomes the same in developed region. The FSR could be classified into two regimes; twin flame spread and single flame spread after the extinction of positive voltage (SF+). in each regime, three sub-regimes are identified depending on S and VDC. in each regime, FSR could be characterized by S and VDC The variation of FSR was explained by thermal balance mechanism with ionic wind effect. in high intensive of voltage, the flames were extinguished, at excessive voltages, an electrical short occurred.