Computational study of two phase flow in pressure swirl atomizer using entirely Eulerian model

Abstract

Atomizers are used in many engineering applications including spray combustion in furnaces, diesel engines, gasoline direct injection (GDI) engines and gas turbine engines. They are also commonly used in applying agricultural chemicals to crops, paint spraying, food processing and cooling of nuclear cores. Pressure swirl atomizers occupy a special position amongst other atomizers because they differ in quality of atomization, simplicity of construction, reliability and low pumping power requirements. Turbulent mixing of liquid and gas in these atomizers is indispensable considerations in the process of atomization. This paper presents a recent Eulerian modelling of two-phase flow in a pressure swirl atomizer using Computational Fluid Dynamics (CFD) STAR-CD code in order to assess its capabilities. In this novel ?-Y-liq atomisation model, an Eulerian description is applied to solve the two-phase flow assuming both liquid and gas phases as a single continuum with high-density variation at large Reynolds and Weber numbers. The transport equations for the liquid mass fraction and interfacial surface density as well as the average density of the liquid and gas phases are modelled, liquid dispersion correctly captured and their numerical results presented. The standard k-? turbulence model accurately captured the effects of turbulence in the flow. The results also show atomization characteristics such as droplet velocity and predicted droplet Sauter Mean Diameter (SMD) with reasonable order-of-magnitudes. Parametric studies were conducted to analyse the influence of liquid viscosity, surface tension, atomizer exit orifice diameter on the spray droplet Sauter Mean Diameter (SMD) at different locations on the spray centreline and radial distances from the symmetry line of the atomizer. The results show reduction in the droplet Sauter Mean Diameter (SMD) for the model as these liquid properties and design variable decrease. � 2018 Author(s).