We are engineering students who are working on a project about injection. Our goal is to simulate the injection of droplets of fuel with the size of 25μm. We tried to begin with an example given by Palabos V1.5r1 (vofMultiPhase) with a droplet which fall with zero velocity by using the recommended data (1. Kinematic viscosity in physical units 1.e-3m^2/s; 2. Surface tension in physical units 0.0728N/m; 3. Contact angle 90.0 degrees; 4. Kinematic viscosity Ratio 2.0; 5. Density Ratio 0.01; 6. Number of lattice nodes for the sphere radius 9; 7. Time step in physical units 1.e-5s; 8. Model (kinetic / dynamic / constRho) dynamic; 9. Maximum number of iterations 500000) but the results crashed after few iterations. We found that this problem works with the previous version of Palabos (V1.4r1) but when we want to make it work with physical data, we encountered issues. We tried it for the water and fuel with respectively:
Water: 1.e-6 - 0.0728 - 90 - 17 - 1.e-3 - 9 - 1.e-5 - dynamic - 500000
Fuel: 3.7.e-7 - 0.0216 - 90 - 42 - 1.52e-3 - 9 - 1.e-5 - dynamic - 500000
We tried it for several couples of time steps and number of iterations but it still does not work, we reached only a few iterations before it crashed…
We also tried to reduce the size of the droplet to reach the size of 25μm (we also reduced the sizes of the domain to keep the same ratio), but it didn’t work at all this time.
Have you some explanations about these issues?
Thank in advance.
We look forward to hearing from you.
Pauline, Basile, Valentin