超声速气流中液体横向脉冲射流一次破碎的大涡模拟

Large Eddy Simulation of Primary Breakup of Transverse Pulsed Liquid Jet in Supersonic Flow

为改善超燃冲压发动机液体燃料的雾化和混合效果,提出一种液体横向脉冲喷入超声速气流的喷注方式,并进行数值计算以探究射流脉动对一次破碎的影响.使用两相流大涡模拟(LES)算法计算超声速气流中液体的雾化,使用CLSVOF方法追踪气液界面,可压缩流动求解器求解气相,不可压缩求解器求解液相.结果表明:脉冲射流的表面破碎和液柱破碎都得到了增强,射流破碎长度显著缩短,在所研究的脉冲频率方案下,脉冲引起的不稳定性会替代Rayleigh-Taylor不稳定性,主导射流一次破碎;由于射流速度的脉动,脉冲射流的穿透深度相比于稳态射流可以提高20%,尾迹区宽度可以扩大25%,展现了更好的雾化和混合效果.

In order to improve the atomization and mixing performance of liquid fuel in scramjet engines,a method of transverse pulsed injection into supersonic flow was proposed,and numerical calculation was carried out to investigate the effects of liquid jet pulsation on the primary breakup.The two-phase flow large eddy simulation(LES)algorithm was used to calculate the liquid jet atomization in the supersonic flow,and the coupled level set and volume of fluid(CLSVOF)method was used to track the gas-liquid interface.The compressible flow solver was used to obtain the gas phase,and the incompressible solver was used to obtain the liquid phase.The results showed that the surface breakup and liquid column breakup of the pulsed liquid jet were enhanced,and the jet breakup length was significantly shortened.In the studied regime of the pulsation frequency,the instability due to pulsation replaced the Rayleigh-Taylor instability and dominated the primary breakup of liquid jet.Due to the pulsation of the jet velocity,the penetration of the pulsed jet can be increased by 20%in comparison with the steady jet,and the width of the wake region can be expanded by 25%,showing better atomization and mixing performance.