Numerical Modeling of Liquid n-heptane Pool Fires based on Heat Feedback Equilibrium

Abstract

Liquid free burning pool fires usually could maintain at a steady burning rate under a certain environment. Due to that the burning rate and the heat feedback could reach a steady self-equilibrium state. Based on mathematical analysis of the equilibrium process, a new modeling approach of liquid pool fires was developed and validated by liquid n-heptane pool fire experimental data. The difference between actual heat feedback and sustainable heat feedback clearly reveal the positive feedback process towards the equilibrium mass burning rate, which is given when the difference is zero. From the modeling results, the heat feedback difference increases from zero at zero burning rate in the positive direction, then drops in the negative direction above a certain burning rate.The equilibrium mass burning rates were close to the experimentally measured values for the n-heptane pool fires under two different environmental pressures. Other flame characteristics, such as axial temperature, absorption coefficient and radiative heat flux were generally in good agreement with the available experimental measurements. The mathematical analysis and numerical modeling of the n- heptane pool fires improve the understanding of the interaction mechanism between liquid fuel evaporation and burning behaviors for free burning pool fires.