Numerical simulation of primary atomization process of liquid jet in subsonic crossflow

Studies of primary atomization of liquid transverse jets in subsonic crossflow consider surface waves as the main cause of jet fragmentation. The characteristics of surface waves during jet fragmentation have been initially analyzed, but there is a lack of understanding of the mechanism of surface wave generation and development. This paper investigates the primary atomization of liquid transverse jets in subsonic crossflow based on the numerical method of Large Eddy Simulation (LES) with the coupled level set and volume of fluid method (CLSVOF) interface tracking, combined with adaptive mesh encryption techniques, where the liquid phase medium is water. This paper focuses on the fine structure of the primary atomization of the jet column, including the evolution of the jet column and the process of shedding the surface of the jet column, to clarify the physical process of primary fragmentation of the jet. The near-field flow structure and gas–liquid interaction are also analyzed to investigate the mechanism of primary atomization of liquid transverse jets and the mechanism of surface wave generation and development in subsonic flows. The results show that the shear action of gas and liquid leads to the generation of Kelvin–Helmholtz (KH) unstable wave, and KH surface wave dominates the surface breaking of jet column. The extrusion of gas and liquid results in the unstable fluctuation of Rayleigh–Taylor (RT), and the RT surface wave dominates the jet column, and finally the cylindrical fracture occurs. The development trend of RT surface wave is to increase the wavelength along the jet direction. When the wavelength of the RT surface wave develops from 0.12 mm to 1.2 mm, the jet column will be columnar broken at the trough of the last RT wave.