Experimental investigation of the effect of gaseous fuel injector geometry on the pollutant formation and thermal characteristics of a micro gas turbine combustor

Experimental investigations of the effects of a new gaseous fuel injector on the performance of a micro gas turbine combustor have been conducted. The new injector which is called swirl injector exerts a swirl-like motion on the fuel flow to increase air-fuel mixing in the combustor. The results, including temperature distribution in the secondary zone of the combustor, NOx, CO, and CO2 emissions, thermal power, and pattern factor are compared with the conical injector configuration. The results show that the temperature distribution is more uniform, both at the secondary zone and outlet section of the combustor in the swirl injector configuration, and the pattern factor of the combustor is reduced by a factor of two. Moreover, the mean outlet temperature of the combustor is higher in the swirl injector configuration which leads to increased thermal power and combustion efficiency up to 12%. Analysis of the emission of the combustor reveals that the CO emission can reduce to half in the swirl configuration at high fuel flow rates. NO emission, however, is two times higher in the new configuration at low fuel flow rates, but at higher flow rates the NO emission is equal to the conical injector configuration. (C) 2021 Elsevier Ltd. All rights reserved.