Numerical investigation of particle spray size distribution in turbulent jet flow

Document Type : Original Article

Authors

1 Laboratory of fluid mechanics, mechanical power engineering, Faculty of Engineering (Elmataria), Helwan University, Cairo, Egypt

2 Laboratory of fluid mechanics, mechanical power engineering, Faculty of Engineering (Elmataria), Helwan University, Cairo, Egypt Laboratory of fluid dynamics and Technical Flows, University of Magdeburg “Otto von Guericke”, Magdeburg, Germany.

Abstract

Injection of spray in turbulent jet flow is involved in many different applications. In this work, a parametric 2D numerical study is performed for a specific configuration similar to a novel burner (SpraySyn) developed at Duisburg-Essent University (Germany). This burner was designed to generate nanoparticle from a spray flame. In order to control the size of nanoparticles, a clear understanding of flow field, temperature and dispersion is necessary. The present study focuses on non-reacting flow (without considering the reaction), to examine the droplet-turbulent interaction. Impact of four different parameters on the flow field, temperature and droplet size distribution, are investigated. These parameters are injection velocity, injection nozzle radius, injected liquid, and injection model. It has been found that increasing the injection liquid velocity from enhances the heat transfer and particle size distribution (due to breakup). The nozzle radius of the injection nozzle has a significant impact on the particle size distribution (PSD) and heat transfer; where increasing the nozzle radius produces small droplets (diameter <67 µm). On the other hand, a decrease in the radius, increases the residence time of the droplet. Using ethanol or n-heptane as injected liquid results in a significant change in the particle size distribution and a minor impact on the flow field. Changing the type of injection model “the single type (monodisperse) and surface type injection (polydisperse)” results in a change in the particle size distribution, at successive time, where more smaller droplets appear in case of the monodisperse compare to the polydisperse.

Keywords