Taking a three-stage radial combustor as the research object and using natural gas as fuel

the combustion performance of lean ignition

lean blowout

outlet temperature field and pollutant emission were experimentally studied under conditions with different fuel ratios and combustion modes. The results show that

in the mode of annular zone diffusion and premixed combustion in the main combustion zone

the fuel-air ratio of lean ignition was 0.027 0～0.040 1

and that of lean blowout was 0.006 9～0.005 5. When the annular zone was changed into premixed combustion mode

both the fuel-air ratio of the ignition and the blowout increased. With an increase in equivalence ratio of the main combustion zone

the outlet temperature coefficient gradually improved

but deteriorated when the equivalence ratio was 0.54. When the equivalent ratio of the main combustion zone was 0.51

the outlet temperature coefficient improved obviously. The mass concentration of CO

unburned hydrocarbon(UHC)

NO_x and soot emissions decreased with the increasing equivalence ratio in the main combustion zone

but the NO_x emission increased when the equivalence ratio reached 0.54. When the annular zone was changed to premixed combustion mode

the pollution indexes decreased slightly. It suggests that the combustor should adopt the annular zone diffusion and main combustion zone premixed at lower loads

and the whole premixed combustion mode at higher loads.