Deformation and breakup of the liquid ligament with various disturbances on the interface in shear flow

TL;DR

This paper numerically investigates how various disturbances and turbulence in shear flow influence the deformation, breakup, and atomization quality of a liquid ligament, revealing that higher wavenumber disturbances accelerate breakup and improve droplet uniformity.

Contribution

It introduces a detailed numerical analysis of the effects of interface disturbances and turbulence on liquid ligament breakup in shear flow, highlighting the impact of disturbance wavenumber on atomization.

Findings

Higher shear velocities promote turbulence and faster ligament breakup.

Increasing disturbance wavenumber accelerates ligament deformation and droplet formation.

Uniform droplet sizes improve atomization quality.

Abstract

This study performed a numerical analysis of the deformation and breakup of a liquid ligament with various disturbances on the interface in shear flow. The shear flow generates a three-dimensional flow and vortices around the liquid ligament. These vortices promote the movement of the liquid inside the liquid ligament. When the velocity difference of shear flow increases, a nonlinear effect becomes strong, and turbulence with higher wavenumber components than the initial disturbance occurs at the interface. This turbulence accelerates the ligament splitting and increases the number of breakup droplets. Then, the droplet diameters become uniform, and the atomization quality improves. As the wavenumber of the disturbance applied to the interface increases, the liquid moving velocity along the central axis of the liquid ligament increases. Furthermore, the breakup time of the liquid ligament becomes short. In addition to the initial reference disturbance with a low wavenumber, when turbulence with twice the wavenumber of the reference disturbance is applied to the interface, the interface deformation and the splitting of the liquid ligament are similar to those with the single reference disturbance. When turbulence with four times the wavenumber is added to the initial disturbance with the low wavenumber at the interface, the deformation of the liquid ligament is accelerated, and the liquid ligament splits faster. Additionally, the number of breakup droplets increases; hence, the total surface area of the liquid increases. The droplet diameter becomes uniform; therefore, the atomization quality of the liquid ligament is improved.