To reveal the effects of air flow-rate distribution on emission characteristics of trapped vortex combustor and understand the generating processes of emissions as well as the factors affecting the processes

a trapped vortex combustor with different centric bluff body width was designed. And the combustor was designed to be fueled only in cavity. Emission experiment was conducted at atmospheric pressure. And inlet temperature of the combustor was kept at 200℃. Inlet Mach number varied from 0.15 to 0.3.Atomization quality

cavity equivalence ratio in combustion zone

and inlet Mach number and residence time influenced emissions in combustors. Generally

improvement of atomization quality and increase of cavity equivalence ratio can enhance combustion process and consequently reduce emissions of CO and HC. However

it will also lead to increase of NOx emission. As cavity equivalence ratio is relatively lower

CO emission curves decline gradually

and even ascend in some cases. HC emission curves descend rapidly here. This is mainly because the consumption of HC is much faster than CO. When cavity equivalence ratio is increasing

the fueling pressure is elevated and thus atomization is enhanced

so vaporizing time of fuel spray is shortened. This will result in rapid decline of HC emission. Although

a large amount of CO will be produced and there is no enough time to consume. CO emission declines rapidly when cavity equivalence ratio is high enough because of the higher temperature in the combustion zones. In gas turbine combustors

the producing and consuming process of NOx is very complicated

and there is no enough data to demonstrate it. Comparison between different bluff body widths has been made as the cavity air flow-rate on front wall are similar. And it reveals that the emissions of CO and HC are mainly determined by the cavity condition. However

NOx emission is also impacted by the mainstream.