Analytical modelling of laminar drag and freestream turbulence eddies on droplet breakup criterion for internal combustion engines

Abstract

The paper presents novel analytical droplet breakup criteria, on Weber number (We)-relative turbulence intensity and We-Ohnesorge (Oh) representations, based on the critical Weber number. The We-Oh analytical criterion stressed the importance of turbulence effects on We-Oh breakup criterion at high We-Oh applications. In developing the analytical models the energy criterion for a disturbed parent droplet to disintegrate and the dual-timescale for turbulent shear in droplet dispersion were considered. The present model has an advantage over to two popular droplet breakup criterion models (Pilch-Erdman and Kolev) because the present model has the ability to support a parametric investigation of droplet breakup characteristics in turbulent flow fields. The Weber-relative turbulence intensity and We-Oh analytical breakup criteria are in good agreement with published experimental data. It is envisaged that the analytical model will be incorporated into larger CFD codes for spray simulation. The continuous research in this important area will present the next generation fuel injectors for improved fuel economy of internal combustion engines, especially high-pressure direct injection engines. The model has the potential to be applied in other natural and engineering systems.