Investigation of emissions for concentric staged lean direct injection combustor

The concentric staged lean direct injection combustor is proposed to satisfy the requirements of emission regulations, the main feature of this novel combustor is that pilot and main stage are using non-premixed combustion concept, and the co-axial airblast atomizer is used in the main stage. The characteristic of combustion efficiency and gaseous emissions at different inlet conditions were investigated by experiments. The results show that the combustion efficiency is greater than 99% when the pilot stage is working alone, as the fuel air ratio increases, the production of CO and UHC decreases, but the production of NOx increases. When the pilot and main stage are working together, the combustion efficiency is extremely high, and the equivalence ratio distribution of combustion zone becomes uniform as the main stage fuel ratio increases, which induce the NOx formation decreases, however, the NOx formation is almost unchanged with main stage fuel ratio when the most total fuel air ratio of combustor is relatively high.