| The atomization of liquid fuel is a crucial process for aero-engine combustion chamber and is one of the key technologies to solve the problem of aviation engine combustion chamber.Dual-orifice pressure-swirl atomizer is widely used in aircraft engine combustor,thus expanding the fuel flow control scope of simplex pressure atomizer,and ensuring the quality of atomization,ignition performance and wide range of lean blowout.Based on dual-orifice pressure-swirl atomizer as the research object,using theoretical analysis,experimental research and numerical simulation to study atomization characteristics of the flow coefficient,spray cone angle,flow circumferential distribution,inner and outer flow,for the dual-orifice pressure-swirl atomizer design provides a theoretical support.The experimental system of dual-orifice pressure-swirl atomizer with timing control and precise adjustment is built.The influence of different working condition parameters and working modes on the atomization characteristics of dual-orifice pressure-swirl atomizer are studied through the atomization system.The experimental results show that both flow rate and atomization Angle increase with the increase of pressure drop,but the increase gradually decreases.While the primary and secondary fuel passage work at the same time,the spray angle is smaller than the atomization angle of primary fuel passage due to the influence of the air entrainment or the change of oil film interaction between primary and secondary fuel passage.Then the semi-empirical relationship between the atomization characteristics of dual-orifice pressure-swirl atomizer is presented based on the theoretical analysis and experimental data.LBM numerical simulation is used to study the influence of working condition parameters and geometric structure on the internal and external flow field of dual-orifice pressure-swirl atomizer.The results of numerical simulation indicate that there are three different interaction states of oil film between primary and secondary fuel passage:the confluence state,the collision state and the separation state.The pressure drop of primary and secondary fuel passage,oil orifice length and spin chamber convergence angle of primary fuel passage will cause the change of interaction state.Different state of interaction has significant influence on the atomization characteristic parameters,such as the film thickness,the fracture length,the spray angle,and so on.For the convenience of engineering to design application,an atomizer design platform for automatic atomizer modeling and atomization characteristics analysis is developed,which is based on UG8.0 secondary development platform and atomization characteristics obtained from experiments and numerical simulation. |
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