Study On The Simulation Of Flow Pattern Inside Effervescent Atomizer And Breakup Of Droplets In The Atomization Sprays

Atomization spray exists widely in nature and people’s life. With the development of industrial technology, the atomized liquid media are not limited to the traditional single-phase and low- viscosity fluid, but would expand to liquids with complex physical properties, such as viscous solutions, viscoelastic liquids, non-Newtonian fluid and so on. Newtonian liquids can be atomized well during traditional atomizer, but the traditional atomizer does not performance very well for viscoelastic liquid s. And results of many studies have shown that effervescent atomization is a new method performing well in atomizing complex liquids. So this thesis focuses on effervescent atomization, and contents two parts of research which are the effects of two-phase flow patterns inside effervescent atomizer for atomization and primary atomization model.The first part is the effects of two-phase flow patterns inside effervescent atomizer for atomization. In this part, two-phase flow patterns inside effervescent atomizer are simulated using the model VOF in ANSYS Fluent. The simulation is aimed at getting the effect of two-phase flow patterns inside effervescent atomizer for atomization. Firstly, this thesis analyses the effect of ALR for forming annular flow. Secondly, it analyses the effect of the caliber’s size of atomizer’s outlet for improving efficiency of forming annular flow. Lastly, it analyses the effect of orifices’ number, it says adding orifices properly can make the void fraction of outlet in a good area and get good atomization. The simulated outcome says adding orifices and reducing the size of caliber’s size of atomizer’s outlet can improving effervescent atomizer’s property.The other part is about the atomization process of liquids, and primary atomization models are established in this thesis. The primary atomization model should be established based on some assumptions and instability analysis of dispersion relation proposed by Goren & Gorttlieb and Joseph et al.. Comparing the models with experimental data, the result shows two models can predict the atomization properties correctly. What’s more, the model from Joseph’s dispersion relation is better.