Experimental investigation on heat transfer mechanism and flame spread behaviors over RP-3 aviation kerosene under lateral flow

Flame spread under lateral airflow exhibits distinct flame behaviors and heat transfer mechanisms compared to concurrent and opposed flow configurations, yet this scenario remains insufficiently understood. In this work, flame spread behaviors under lateral flow for different pool widths were systematically investigated. Results show that the increasing flow speed causes a transition from pulsating to uniform flame spread, accompanied by the emergence and evolution of flame streaks regardless of pool width. Flame spread rate displays a non-monotonic dependence on the lateral flow speed, leading to three distinct stages based on the evolution of dominant mechanisms of heat transfer. Heat transfer measurements reveal that subsurface convective heat transfer in liquid phase dominates in narrow pool, whereas gas-phase heat feedback becomes significant in wide pool. Accordingly, a model of subsurface flow velocity for narrow pool is established incorporating sidewall viscosity effects. Moreover, flame convective heat transfer is enhanced while radiation is suppressed with enhanced lateral flow, resulting in convective dominance in the gas-phase heat feedback. Additionally, an equation of convective heat flux is proposed using the lateral heating length and mix-flow theory. Finally, a theoretical model for predicting flame spread rate is proposed in narrow and wide pools respectively based on the dominant heat transfer mechanisms.