Modeling high-speed viscous liquid sheet atomization

A linear stability analysis is presented for a liquid sheet that includes t he effects of the surrounding gas, surface tension and the liquid viscosity on the wave growth process. An inviscid dispersion relation is used to ide ntify the transition from a long wavelength regime to a short wavelength re gime, analogous to the first and second wind induced breakup regimes of cyl indrical liquid jets. This transition, which is found to occur at a gas Web er number of 27/16, is used to simplify the viscous dispersion relation for use in multi-dimensional simulations of sheet breakup. The resulting dispe rsion relation is used to predict the maximum unstable growth rate and wave length, the sheet breakup length and the resulting drop size for pressure- swirl atomizers. The predicted drop size is used as a boundary condition in a multi-dimensional spray model. The results show that the model is able t o accurately predict liquid spray penetration, local Sauter mean diameter a nd overall spray shape. (C) 1999 Elsevier Science Ltd. All rights reserved.