M Farahnak - MSc Student of Mechanical Engineering Department of Shahrood University of Technology
A. SarreshtehdarI - Assistant Professor of Mechanical Engineering Department of Shahrood University of Technology;

This article represents the numerical simulation of circular liquid jets that discharge from different circular orifices in to ambient atmosphere based on experimental researches data in breakup characteristics of circular and elliptical liquid jets conducted by Kasyapet. al (2009). A comparison is performed between the break up in circular jets with different orifice exit diameter. Also the effects of variations of discharging velocity fromorifices on the beak up of liquid column have been examined. Water and water-glycerol mixture are used as working liquids. OpenFOAM® and the solver of interFoam which solves the two phase flows by capturing the interface using a VOF method is used to numerical simulation The characteristics of the liquid jet are described by non-dimensional numbers. The break up curves in circular orifices for water and water and water-glycerol mixture can be extracted through numerical simulation data. Breakup length of the circular jet increases linearly with jet velocity in a range of low jet velocities. As jet velocity increases, the ambient atmosphere starts influencing the liquid jet and asymmetric waves or transverse waves begin to grow on the jet surface. Also the effects of viscosity and ambient medium in the analysis of liquid jet breakup is changing thewavelength of the most unstable disturbance. The results confirmed the results of the experiments qualitatively.

numerical, breakup, circular orifice, viscosity