The purpose of this paper is mainly the comparison of radiation effect using
nongrey model by analyzing method with that using grey model in droplet cumbustion. The
discrete ordinate method (DOM) was employed to solve the radiative transfer equation (RTE)and the weighted sum of grey gases model (WSGGM) was applied to model a nongrey
radiation effect by C02 and H20 gases. In the present study, nongrey effects were clearly
appeared respectly. To present nongrey effects, many parametric studies were carried out. The
result was shown that the ignition delay time became shorter, the radiative heat flux from
gaseous medium to droplet increased, the flame became thinner, and combustion products
decreased than grey model. This indicated the grey model was underestimated in radiationprocesses. So, nongrey model must be considered in any combustion phenomena.