The air split of the second stage of the radial swirler was taken as the main design parameter for the ignition and extinction characteristics. Test study showed that the fuel in the chamber

atomized by the co-rotating swirler cup with strong swirl number

has been basically atomized at ignition and lean blow-out conditions of atmospheric pressure and room temperature as a stable fuel atomized at the air-fuel-ratio greater than 3. The droplet had sufficient secondary atomization when the air split ratio of the primary and the second stage of swirlers changed from 0.8 to 1.2

making the swirl cup droplet Weber number greater than 40. Therefore

increase of the second stage of swirler air split will not further improve the atomization quality

there is no influence on the ignition and extinction characteristics.