Numerical Simulation of Liquid Sheet Deformation Caused by Air Flow

Abstract

A liquid-fuel sheet injected into the combustor of gas turbine engines is deformed and atomized as a result of the complex interactions between the liquid and air flows. However, the effects of the fluid properties and velocities of the gas and liquid on liquid sheet oscillation have not been clarified yet. In this paper, we performed two-dimensional (2-D) numerical simulations of an oscillating liquid sheet using a volume tracking method to investigate the effects of densities, velocities, viscosities and momentums of the gas and liquid phases on the growth rate and wavelength of the liquid sheet oscillation. As a result, we obtained the following conclusions. The oscillation of a liquid sheet is suppressed by the atomizer lip, which forms a wake in its downstream. The gas velocity gradient at the gas-liquid interface is a dominant factor in the growth of liquid sheet oscillation, which depends not mainly on gas velocity but on liquid velocity due to the lip. Gas and liquid viscous forces slightly reduce liquid sheet oscillation. The wavelength of the oscillation is in inverse proportion to the square root of the momentum flux ratio.