Effects of radiative heat loss on the propagating speed of spherical flames

The effects of radiative heat loss on the propagating speed of spherical flames are systematically studied by theoretical analysis and numerical simulation. It is found that there are two different effects of radiative heat loss: (1) the direct effect by which the flame temperature and thus the flame propagating speed are reduced due to the radiative heat loss; and (2) the indirect effect by which the flame propagating speed is reduced by the incoming flow toward the flame front which is caused by the radiation cooling. For mixtures near their flammability limits, the direct effect dominates; while for mixtures with high radiative intensity, the indirect effect dominates. The results presented in this study are important for experiments in which the laminar flame speed is measured by outwardly propagating spherical flames.EI05883-8863