Numerical study of the effect of the initial velocity fluctuations of a rotating conical liquid sheet on secondary atomization

To investigate the influence of initial instability waves on the secondary atomization of a rotating conical liquid sheet, this study adopted a numerical simulation method. By varying the initial velocity of the liquid sheet to simulate the initial instability waves, the effects of sinusoidal fluctuating velocities under different frequencies and amplitudes on secondary atomization were investigated. The research demonstrates that the characteristic parameters of secondary atomization undergo regular changes with increases in the frequency and amplitude of the initial velocity fluctuations of the liquid sheet. Furthermore, the direction of these changes (increase or decrease) periodically reverses depending on the axial position or the moment of observation. The initial velocity fluctuations of the liquid sheet form ring-shaped droplet-dense regions along the axis of the spray field. Variations in frequency and amplitude lead to changes in the droplet number distribution within each droplet-dense region, as well as alterations in the droplet distribution on the inner and outer sides of the spray cone in the radial direction. In addition, the influence of the velocity fluctuation frequency on the secondary atomization characteristics and the spatial distribution characteristics of the droplets is significantly greater than that of the amplitude. This study provides insights for regulating the droplet size and spatial distribution characteristics of the spray field, contributing to reliable prediction and control methods for the design of high-performance advanced combustion chamber nozzles.