Experimetnal study on burning behaviors of liquid fuels with different sooting levels at high altitude

To validate the feasibility of classical fire scaling laws under low pressure, three typical liquid fuels with different sooting levels, i.e. ethanol, n-heptane and jet-A, were employed in this paper to perform a sequence of pool fires in a high-altitude city, Lhasa (3650 m, 64.3 kPa). Mass loss, axial temperature profile and radiative heat flux were recorded in each test. From the assessment of experimental data, it can be concluded that the dimensionless burning intensity m" μ/D/D can be correlated against the Grashof number to different powers for all the three fuels, and the exponent increases with the sooting level of fuels. A correlated relationship expressed as ΔT~[z(P/Q)^2/5]^η can be applied to analyze the axial temperature rises, partitioning flame region, intermittent region and plume region with the modified demarcations, i.e. 0.42 and 1.06. In addition, the averaged flame temperature grows higher with declining sooting level of fuels, while the radiative heat fluxes exhibit the opposite results. Moreover, the measured radiative heat fluxes for different fuels are proportional to L_mT₅^f, and the soot volume fraction apparently increases with the sooting level of the fuels under low pressure condition.