Numerical investigation on air-fuel configurations on the emission features in a vortex flameless combustion at various thermal intensity.

A numerical study on the effects of air/fuel configuration on NOx emissions control using methane fuel combustion at different thermal intensity was conducted in this paper. The investigation employed the structure of small combustors which are influenced by some combustion factors. The layout is produced through diverse air and fuel injection configurations selected due to their potential on distinct combustion characteristics. In reverse configurations mode, the air injection port is located at the exit end of the combustor; while in the forward configurations, the air injection port is placed at the reversed end of the combustor exit, with a change of fuel position. Our investigation indicated that in both non-premixed and premixed combustion modes, the NOx discharge is extremely low. However, in premixed combustion mode, the forward and reverse flow configuration (FP, RP) premixed produced a significantly low level of NO and CO compared to the other air configurations in non-premixed at all equivalence ratios Φ The investigation observed that any changes to the fuel injection position affect the mixture preparation, resulting in premature combustion at very low emissions, hot spots and increased emissions. The reverse-cross-flow configuration (RC1) has more potential to attain lower NO (approximately 1.30E-05 ppm) together with low CO (approximately 223 ppm) emissions when compared to the other flow configuration (RC2 and RC3). More so, a lower combustor volume leads to a very high thermal intensity of 324–393 MW/m3-atm thus resulted in a reduced residence time and gas recirculation, and high CO and NOx emissions. [ABSTRACT FROM AUTHOR]