A Numerical Study of Concurrent Flame Propagation Over Methanol Pool Surface

摘要

Concurrent flame spread over methanol pool surface under atmospheric conditions and normal gravity has been numerically investigated using a transient, two-phase, reacting flow model. The average flame spread velocities for different concurrent air velocities predicted using the model are quite close to the experimental data available in the literature. As the air velocity is increased, the fuel consumption rate increases and aids in faster flame spread process. The flame initially anchors around the leading edge of the pool and the flame tip spreads over the pool surface. The rate of propagation of flame tip along the surface is seen to be steady without fluctuations. The flame spread velocity is found to be nonuniform as the flame spreads along the pool surface. The flame spread velocity is seen to be higher initially. It then decreases up to a point when the flame has propagated to around 40% to 50% of the pool length. At this position, a secondary flame anchoring point is observed, which propagates toward the trailing edge of the pool. As a result, there is an increasing trend observed in the flame spread velocity. As the air velocity is increased, the initial flame anchoring point moves downstream of the leading edge of the fuel pool. The variations of interface quantities depend on the initial flame anchoring location and the attainment of thermodynamic equilibrium between the liquid- and gas-phases.