Experimental investigation on the combustion phenomena and heat transfer mechanism of ethanol spill fire with different initial fuel temperatures.

The process of fluid diffusion and fire dynamics in spill fires at different initial temperatures is unstable and complex, potentially leading to severe consequences. Through a series of experiments, the effects of initial fuel temperature on the combustion mechanism of ethanol spill fire were investigated. The results show that in the liquid-phase control stage, the propagation of the spill fire is greatly affected by the liquid spread, and the increasing rate of combustion area (IRCA) and the maximum combustion area (MCA) gradually increase with the increase in the initial temperature. In the gas-phase control stage, the propagation of spill fire is greatly affected by the combustion of liquid, as initial temperature increase, the IRCA and MCA gradually decrease. The increase in the initial temperature will lead to the attenuation of the pulsation phenomenon during the propagation of the flame, but will lead to the frequency of flame oscillation increases. The prediction equations of burning rate at different initial fuel temperatures are established, which show that there is a significant difference in burning rate in the liquid-phase control stage, the maximum increase in the burning rate was only 2.3%, while in the gas-phase control stage, this value is about 50%. The convective feedback is the main heat feedback mechanism of small spillage fires, and the convective feedback accounts for more than 62.5%. The higher the initial temperature, the stronger the convective feedback mechanism. [ABSTRACT FROM AUTHOR]