A new property evaluation scheme for mass transfer analysis in fire problems

Abstract

A simple scheme for the estimation of average thermo-physical properties has been presented. Properties such as thermal conductivity and specific heat have been calculated at suitable temperatures, which are functions of the ambient and the adiabatic flame temperatures. These have been successfully employed in the empirical correlations available in standard combustion text books for the estimation of burning rate constants and flame stand-off distances in the combustion of liquid and solid fuels. The average thermal conductivity is estimated as the thermal conductivity of standard air calculated at a temperature given as one-third of the sum of ambient and the adiabatic flame temperatures. The average specific heat is calculated as the specific heat of standard air at the adiabatic flame temperature itself. Extensive validation of the scheme with the experimental data is presented employing several liquid fuels and a solid fuel.