Development of full spectrum correlated k-model for spectral radiation penetration within liquid fuels

Abstract

In this paper, full spectrum correlated k-distribution (FSCK) models are developed for several liquid fuels including decane, ethanol, ethylene glycol, heptane, and toluene. The models were built using high-resolution absorption spectra, collected from the literature. To validate the novel FSCK models, they were used to solve radiative heat transfer within liquid pools assuming three temperature profiles (i.e. constant temperature, linear and nonlinear temperature profiles) and the calculated transmissivity and radiative heat source of FSCK were compared with those of using high resolution absorption spectra and the gray models implementing Planck mean absorption coefficient. The sensitivity analysis was performed for the accuracy of the FSCK results with number of quadrature points for different fuels. Using seven quadrature points for FSCK model has been found to be sufficient for providing good accuracy of spectral radiative heat transfer within the liquid fuels with a reasonable computational cost. Moreover, we studied the effect of the reference temperature used in FSCK model and found out that for the pool fire scenario, the FSCK provides its best accuracy if an equivalent temperature representing the radiation feedback from the flame is used as the reference temperature. Comparison of computational costs of high-resolution spectral radiation calculations and FSCK method revealed a significant computational gain by use of FSCK model.