A problem of spray combustion has been of vital importance in practical combustors, furnaces, gas turbines, diesel engines and liquid propellant rocket engines, so that its complete understanding was in high demand. But it includes complex processes such as droplet collision, secondary breakup, evaporation and interaction with turbulences as well as turbulent mixing, chemical reaction and radiation. Therefore, it is not only one of the most difficult processes to model mathematically, but also a very important topic which we must study for its various. applications. Simultaneously, the radiation phenomenon is considered to play a significant role in high temperature system. Especially, it is necessary to be included in a combustion engineering accompanied by chemical reaction and radiatively active medium.
In this study, the effect of nongray radiation has also been incorporated in a problem of liquid spray combustion chamber. The discrete ordinates method (DOM) was employed to solve the radiative transfer equation (RTE) and the weighted sum of gray gases model (WSGGM) was applied to model a nongray radiation effect by $CO_2$ and $H_2O$ gases produced in combustion processes. The absorption coefficients derived from WSGGM were used with DOM by summing solutions of the RTE for each gray gas. The Eulerian-Lagrangian formulation was adopted to analyze the liquid droplet combustion processes in gas flows. The interactions between two phases are accounted for by using the particle source in cell (PSIC) model.
The results have shown that the gasfication of the droplets is enhanced by the radiation effects, which results in faster droplet vaporization. The radiation also led to a broader high temperature zone inside the combustor. Therefore, the radiation effect is indispensably considered in a prediction of spray combustion performance.
