Experimental study on effects of prefilming and non-prefilming atomization on the combustion characteristics in a realistic full annular combustor

The interaction between liquid fuel and the walls poses a major challenge to using the airblast atomizer in the combustor of an advanced aero-engine because the mechanism of this interaction is not fully understood. In this study, the authors experimentally examine the influence of the interaction between liquid particles and the walls on the performance of a full annular combustor in terms of fuel atomization, the characteristics of the flow field, ignition and lean blowout (LBO), the combustion efficiency, and the distributions of temperature at the outlet corresponding to prefilming and non-prefilming methods of atomization. The results show that the Sauter mean diameter (SMD) of the prefilming airblast atomizer was smaller than that of the non-prefilming airblast atomizer when the fuel pressure difference was small. As the fuel pressure difference was continuously increased, the SMD of the prefilming airblast atomizer gradually became larger than that of the non-prefilming airblast atomizer. The morphology of the flow field downstream of the airblast atomizer could be changed by adjusting between the prefilming and non-prefilming modes, i.e., the flow field downstream of the prefilming mode was a typical swirling recirculation zone while that downstream of the non-prefilming mode had a recirculation zone on both sides of the forward jet at the center. When the inlet air flow is small, the ignition and LBO performance of the non-prefilming scheme were better than those of the prefilming scheme. As the inlet air flow was continuously increased, however, the ignition and LBO performance of the prefilming scheme became better than those of the non-prefilming scheme, and it had a higher combustion efficiency under the ground idle condition for different fuel–air ratios. The quality of temperature distribution at the outlet corresponding to the non-prefilming scheme was better than that of the prefilming scheme as well.