Numerical Study of the Effect of the Initial Velocity Fluctuations of a Rotating Conical Liquid Sheet on Secondary Atomization

Abstract

The breakup of a rotating conical liquid sheet is caused by the development of an initial instability wave on the liquid sheet’s surface, but its effect on the secondary atomization is not well understood. In this study, the effect of the sinusoidal fluctuating velocity on the secondary atomization under different frequencies and amplitudes is investigated using numerical simulations, seeking to model the initial instability wave by varying the initial velocity of the liquid sheet. It is shown that the characteristic parameters of the secondary atomization have an obvious correlation with the frequency and amplitude of the initial velocity fluctuation of the liquid sheet, and this correlation is either “positive” or “negative” according to the frequency of the cyclic change. The initial velocity fluctuation of the liquid sheet forms a ring-shaped droplet-dense region in the axial direction of the spray field, and changes in the frequency and amplitude lead to changes in the distribution of the number of droplets in each droplet-dense region, as well as changes in the distribution of the droplets in the radial direction of the inner and outer sides of the spray cone. In addition, the frequency of the velocity fluctuations has a significantly greater effect on the secondary atomization characteristics and the droplets’ spatial distribution characteristics than the amplitude. This study provides ideas for the regulation of the droplet size and spatial distribution characteristics of the spray field and it offers reliable prediction and control methods for the design of high-performance advanced combustion chamber atomizers.