[Saurav_Rath]

Hello everyone,

I am seeking help for a multiphase simulation in a centrifugal chamber.

Objective: Obtain distribution of different phases within the chamber and looking at impact of different densities of solids, viscosity of liquid phase.

Geometry (attached), mesh (poly-hexcore with min cell size ~ 0.05mm)

Materials:
1. Primary - Liquid (same as water)
2. Secondary - Air
3. Secondary - Solids (rho=1077kg/m3 and viscosity = 1.2cP)

Initialization:
1. Patching air with cell register = 1
2. Patching cells with cell register = 0.01

Current case:
- Mixture model with solids as granular phase, implicit
- Whole chamber is rotating so using frame motion at 2100 RPM (in y direction)
- Running transient simulation with delT=1e-5

Challenge:
- Floating point exception within few timesteps
- Even if it works at very low timesteps, the mass of liquid phase is fluctuating leading to mass imbalance.

I have tried converging (to 1e-3 for now) at every timestep, reducing URFs, delT. But the simulation crashes or doesn't run as expected.

Many thanks,
Saurav

[SHAIZA TALIB]

hello, i have a question about how you define the inlet velocities for multiple materials. i am also learning about it. want to see the wind_wave oupling. And I have a 2D channel with height of 5m, 3m water and 2m air. I am using Fluent , K epsilon model plus VOF. Just want to know how to define the inlet velocites.

[Saurav_Rath]

Originally Posted by SHAIZA TALIB

hello, i have a question about how you define the inlet velocities for multiple materials. i am also learning about it. want to see the wind_wave oupling. And I have a 2D channel with height of 5m, 3m water and 2m air. I am using Fluent , K epsilon model plus VOF. Just want to know how to define the inlet velocites.

If I understand correctly, inlet velocities can be provided using multiphase tab in BC. Since it is multiphase, you would have to provide values for each phase.