- Sharif University of Technology
Oxy-fuel combustion is a modern carbon capture and storage (CCS) technique that improves the combustion process and reduces the environmental penalty of many combustion systems. Evidently, the accurate radiative calculation of oxy-fuel combustion is very important to obtain more improved combustion system designs with less environmental drawbacks. In the present study, a small scale unconfined turbulent bluff-body flame is numerically simulated to calculate the gas radiative properties using three different approaches of ignoring radiation, applying a modified version of the weighted sum of gray gases (WSGG) model, and employing the spectral line based weighted sum of gray gases (SLW) model. First, the selected bluff-body flame is validated against experimental data. The early outcome is that the simulation results of three chosen approaches are very close if there is no oxygen enrichment. Next, the effect of oxygen enrichment is carefully investigated imposing the aforementioned spectral radiation approaches. The achieved results indicate that the predicted gas temperature becomes more sensitive to the implemented radiative approach as the oxygen concentration in the oxidizer increases. In very high oxygen enrichment condition, the gas temperature predicted by SLW model shows up to 155 K differences with that of ignoring radiation approach. The simulation results also show that the oxygen enrichment would raise the CO2 and H2O volume fractions in the flame zone. Therefore, the non-grayness of gases becomes more significant in such conditions and the accurate radiative calculation becomes more essential. This is investigated carefully in this study.