Modelling Primary Atomization of a Simplex Nozzle

This paper was produced for the 2019 NAFEMS World Congress in Quebec Canada

Resource Abstract

Modeling the near nozzle flow dynamics is a challenging task. Accurate detailed predictions require transient models for turbulence and liquid-gas interface tracking which are expensive computational models. It is important to use methods that cut the computational cost of running such detailed simulations. One such method is the model transition from interface tracking to the Lagrangian particles for smaller sphere like interfaces.



This work investigates the parameters that influence the spray produced by a simplex nozzle. These parameters include the inlet pressure, choice of turbulence model and mesh types. The simulation is focused on the primary atomization and near field spray characteristics. The near nozzle region flow field was well predicted with a fine mesh. Fluent’s built-in Volume-Of-Fluid (VOF) to Discrete Particle Method (DPM), labelled as VOF-to-DPM transitional model removes VOF blobs in a certain diameter range and transfers them to the DPM model for further tracking. The use of dynamic mesh refinement and coarsening helps in keeping the total computational elements within a uniform range. This approach saves CPU time by allowing coarser mesh in the far region. Further post-processing tools are used to analyse the resulting sizes of the droplets.