Correlation between Volume Fraction and Droplet Distribution

  • Last Post 08 June 2018
mrglobetrotter posted this 08 June 2018

Hello everybody,

I'm currently working on Sprays with Euler approaches in Ansys CFX17 with water and air both as continuous fluid. I would like to make an investigation about the droplet distribution in my results and want to ask, if there is a possibility or a way to get information about the droplet distribution out of e.g. the volume fraction result? Is there a good option available in the software? Is there a mathematical method available? Does anyone know a correlation?

Thanks in advance!

raul.raghav posted this 08 June 2018

Since you mentioned both the phases (water and air) were modeled as "Continuous", there is no way to evaluate the droplet distribution. You would have to define one of the phases as "Dispersed" or "Polydispersed", to evaluate the droplet information. 

Water droplets in air constitute two different fluids that are mixed at the macroscopic level and not the microscopic level. Hence, you need to use a multiphase model and define two distinct fluids, Water and Air. Each fluid contains only one component comprising one material (air or water), whose properties can be defined. Air is the continuous fluid (Continuous Fluid), and Water is the dispersed fluid (Dispersed Fluid).

Please refer to the following as well:

Ansys CFX: Multiphase Flow Modeling

Multiphase Examples

Eulerian-Eulerian Multiphase Versus Particle Transport

Polydispersed, Multiple Size Group (MUSIG) Model