Nitric Oxide Predictions for Low NOx Radial Swirlers With Central Fuel Injection Using CFD

A radial swirl low NOx combustor was investigated using CFD at 0.5 equivalence ratio and 600K inlet temperature at 1 bar. The equilibrium pdf combustion model using 16 species chemistry was shown to give a slightly improved prediction for the temperature distribution, but a poorer prediction for the CO distribution, over similar work using the flamelet model with 53 species chemistry. The NOx model was applied as a post-processing application and was shown to give a vastly superior result for the equilibrium pdf model using 16 species chemistry over the flamelet model using 53 species chemistry. Various NOx model configurations were tested and it was shown that only the mixture fraction based turbulence chemistry interaction model was able to provide a good result and all other models drastically under-predicted the peak nitric oxide levels. Combustion model predicted O modeling with excluded and combustion model predicted OH modeling were both shown to give a good match against measurements for the peak nitric oxide levels within the combustor when using mixture fraction based turbulence chemistry interaction.© 2012 ASME