Learning Forum

[subra284]

Hi all,

I have been trying to simulate the break-up of a droplet as it passes through a micro-constriction using Fluent. I am using the Volume of Fluid (VOF) model. Unfortunately, the droplet does not break-up even in cases where it should have been based on the experimental data I have. I am wondering if anyone here has done something similar to see droplet break-up. Below are my simulation parameters, feel free to weigh in:

• Domain: Microfluidic (cross-section is 1 mm x 0.1 mm, inlet to constriction = 4 mm, constriction to outlet = 6 mm, total length = 10 mm)
• Type of flow: Multiphase (water in oil)
  • Primary phase: oil (continuous phase)
  • Secondary phase: water (dispersed phase)
• Model: Volume of Fluid
• Formulation: Explicit with Sharp interface
• Physical parameters -- density, viscosity, surface tension -- set based on experimental studies
• Boundary conditions based on experiment
  • Oil mass flow rate at the inlet
  • pressure-outlet (P-gauge = 0)
  • no-slip walls with contact angle with respect to water = 180 degrees
• Pressure-velocity coupling: PISO
• Discretization methods
  • Gradients: Least Square Cell Based
  • Momentum: Second Order Upwind
  • Volume Fraction: Geo-Reconstruct
  • Pressure: PRESTO!
  • Time discretization: First Order Implicit (because of explicit VOF)
• Adaptive time stepping from 1E-6 to 1E-4 seconds

Please let me know if any of my settings are incorrect to capture droplet break-up. Any help would be greatly appreciated.

Thanks,

Abhi