{"id":357338,"date":"2024-03-15T18:15:56","date_gmt":"2024-03-15T18:15:56","guid":{"rendered":"\/forum\/forums\/topic\/three-phase-eulerian-simulation\/"},"modified":"2024-03-15T18:18:03","modified_gmt":"2024-03-15T18:18:03","slug":"three-phase-eulerian-simulation","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/three-phase-eulerian-simulation\/","title":{"rendered":"Three Phase Eulerian Simulation"},"content":{"rendered":"

Hi,<\/span>
My question is long but I will appreciate considering it.<\/span><\/p>\n

I want to simulate a mixing tank filled with water, air, and glass beads in Ansys Flunet. The mixing tank is a coaxial mixer comprised of a central impeller, a wall scraping anchor, and a gas sparger. The fluid followa non-Newtonian fluids law (power law) and particles are patched at the bottom of the tank (5%-15%), and I want to model the solid suspention.
I am using three-phase Eulerian model:<\/span><\/p>\n

    \n
  1. Water: Continuous phase<\/span><\/li>\n
  2. Glass particles: Dispersed phase (Granular- constant diameter: 1mm, Granular viscosity: Gidaspow, Frictional viscosity: Schaeffer, Frictional pressure: based KTGF)<\/span><\/li>\n
  3. Air: Dispersed phase (constant diameter: 3mm)<\/span><\/li>\n<\/ol>\n

    Since I want to model solid suspension, Turbulence dispersion is important, So, I used Simonin model for Turbulence disperion and Schiller-Naumann coupled with Brucato modification for Drag coeeficient in all phases interactions.  Also, I used dispersed RNG k-epsilon turbulence model, transient solver, 0.0001s time step, gas velocity inlet 0.1 m\/s, outlet as outflow, central impeller 300rpm, anchor impeller 10 rpm and sliding mesh method.<\/span><\/p>\n

    The problem I have is that some of my residuals (u-air, u-solid, v-solid, w-solid, w-fluid ) are not getting converge and are constant (actually they show a little divergence). I had continuity divergence at the beginning as well. But I solved it by mesh refinement, using coupled scheme, and reducing the relaxtion factors for pressure and momentum to 0.5. Moreover, I encounter backflow when the simulation goes on. <\/span><\/p>\n

    I have some guesses myself:<\/span><\/p>\n

      \n
    1. KTGF model is better for transient fluids, however at the beginning of the mixing, the flow is not fully turbulent. Moreover, I did a couple of simulations without considering Frictional viscosity for solid phase and I saw weak solid suspension. <\/span><\/li>\n
    2. I could not use degassing boundry condition since it is a 3-phase simulation and degassing is only availabe for 2 phase simulation. So, I had to consider back flow in boundry condition and that is why I am getting back flow in my consul as well. <\/span><\/li>\n<\/ol>\n

      I don not think that my mesh needs modifications since I have worked on it a lot.<\/span><\/p>\n

      Any recommendations? <\/span><\/p>\n

      \"\"<\/a><\/p>\n

      \"\"<\/a><\/p>\n

       <\/p>\n","protected":false},"template":"","class_list":["post-357338","topic","type-topic","status-closed","hentry","topic-tag-eulerian-eulerian-1","topic-tag-fluent","topic-tag-mixing-1","topic-tag-non-newtonian","topic-tag-three-phase-flow-1"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t