A comprehensive numerical investigation of the spray characteristics in spill-return atomizers using coupled VOF and Euler-Lagrange approach

This research paper investigates a three-dimensional, two-phase flow dynamics, and atomization characteristics of a spill return atomizer. The method includes the internal flow field, primary and secondary atomization which are modeled using the hybrid approach Volume of Fluid to Discrete Phase Model (VOF to DPM). A comparison between the Large Eddy Simulation (LES) and The k-omega Shear Stress Transport turbulence model (SST k-ω) in combination with the Volume of Fluid (VOF) model, along with the Adaptive Mesh Refinement (AMR) method, to predict the breakup of the liquid core is carried out. The investigation presents axial and tangential distributions of velocity, mean diameter, and spray cone angle of droplets at spray pressures of Spill-to-Feed Ratio (SFR) equal to 0.9. The numerical results are validated against the Phase-Doppler Anemometry (PDA) experiment. A relative error, of less than 7.3%, is recorded. The study systematically explores the spatiotemporal evolution of the flow field, including the liquid surface wave motion, liquid film characteristics, and the formation/atomization of the fluid spray cone downstream of the injector.