Effect of swirl number of pilot stage on TeLESS Ⅱ combustor's lean blow-out performance

The next generation of technology of low emission of stirred swirl (TeLESSⅡ)low-emission combustor developed by Beihang University adopted a central staged arrangement. The center of the dome was classic swirl cup pilot structure which could provide a stable ignition source for the combustor. The main stage arranged outer of the pilot stage which adopted a pre-mixed single axial cyclone design was used to reduce emission. The influence of the combination of the swirl number of the pilot first stage and the secondary stage on the blow-out performance of the combustor was studied. The pilot stage is found playing an important role in the stabilization of flame in low-emission combustor. The gas-oil ratio was measured in the single dome combustor under normal temperature and pressure conditions. The aerodynamic characteristics of different cases were analyzed by numerical calculation. The results show that the higher the total temperature in the recirculation zone is, the lower the gas-oil ratio for lean blow-out is, and the decrease of pilot secondary stage's swirl number isfavorable to the coupling between the flame and flow field. Therefore, the flame in the recirculation zone is more stable and the lean blow-out boundary becomes broader. With the increase of the pilot first stage's swirl number, the gas-oil ratio for lean blow-out is not reduced.