Energy balance in medium-scale methanol, ethanol, and acetone pool fires

Abstract

Several series of measurements were made to characterize medium-scale pool fires steadily burning in a well-ventilated, quiescent, open environment. Time-averaged local measurements of radiative and total heat flux were made in steadily burning methyl alcohol (methanol; CH3OH), ethyl alcohol (ethanol; C2H5OH), and acetone ((CH3)2 CO) pool fires. The fuel lip height in a water-cooled stainless-steel burner was maintained at 10 mm. Schmidt-Boelter heat flux gauges were used to measure the radiative emission to the surroundings. The total heat flux directed towards the pool surface was measured using a Gardon gauge positioned just above the pool surface. A previously developed method was used to calculate the convective heat flux to the pool surface, allowing estimation of the radiative flux, which agreed within experimental uncertainty with a previous measurement in the methanol pool fire. The steady-state mass burning rate was measured using a load cell, and the heat release rate was measured in the exhaust using calorimetry. The energy balance for each of the fires was determined. The results showed that both radiation and convection play significant roles in these pool fires. Radiation was the dominant mechanism of heat feedback to the fuel surface accounting for 68% to 88% of the energy, while enthalpy convected in the plume represented 68% to 78% of the fire's total energy, far exceeding radiative emission to the surroundings.