Effects of radiation on predicted flame temperature and combustion products of a burning liquid fuel spray

The effects of radiative heat transfer calculations on the predicted temperature rise in a burning liquid-fuel spray, are studied. The adiabatic temperature rise resulting from a comprehensive spray combustion model is adjusted for heat transfer to the chamber cooling water by incorporating a radiation model using the Discrete Transfer Technique. The spray combustion model used is of the ‘mixed-is-burnt’ type where combustion is treated as a post process event. The data needed for the combustion post-processor are obtained from an effective property Locally Homogeneous CFD flow model, incorporating a droplet evaporation model to account for the liquid phase. The combustion model itself is based on the minimisation of Gibbs free energy and incorporates kinetic sub-modules for soot formation and oxidation. The results from the combustion model are fed into a radiation sub model for calculating cell emmisivities. These are used to calculate corrective terms for incorporation within the energy balance employed by the combustion model resulting in corresponding temperature (and, subsequently, composition) corrections. The convergence of this iterative process yields results of product concentrations and of temperature throughout the combustion chamber. The predicted results are compared with existing experimental result in a case study. The results are also compared with those obtained from the combustion model with no radiation correction and also with ones obtained with empirical corrections