Flame Spread in Opposed Flow along the Ground Soaked with High-volatile Liquid Fuel

The flame spread in opposed flow through the layered flammable gas mixture along the ground soaked with high-volatile liquid fuel was studied experimentally. The effects of opposed flow velocity on the aspect of flame spread, the velocity of flame spread, the thickness of flammable gas layer and the preheated distance ahead of the flame leading edge were investigated experimentally. If the velocity of opposed flow at about 1 mm above the ground surface is over the flame spread velocity with no surrounding airflow, no flame spread occurs even when the ground temperature is highly above the flash point of the spilled liquid fuel. The velocity of opposed flow has a large effect on the preheat distance ahead of the flame leading edge also. With increase in the velocity of opposed flow, the maximum preheat distance decreases to the local minimum, and increases to the local maximum thereafter. This is due to the balance between the convective cooling by the flow and the heat conduction through the ground beneath the inclined flame in downstream.