[Cheza16]

Hi everyone,
I am new on the forum and I am a beginner with ansys.
For my master degree thesis I have to simulate the separation of mixed air and water within a GLCC separator.
In the following image there are the operational conditions and the dimensions of my separator.
I have drawn my cyclone model on spaceclaim and imported it onto ANSYS, I am looking for guidance for what parameters I should set along with boundary conditions.
I have already tried to perform some simulations (steady state) but I can't manage to have convergence.
These are the steps I followed:
1-I kept the mesh the simplest as possible -with 10 inflation layers- in order to have a quicker solution ;
2-I have chosen a mixture multiphase model (double precision checked), with phase1 being water ( Volume fraction 0.7) and phase2 being air -but I am not sure I am doing this correctly;
3-I have chosen a Viscous k-epsilon model, RNG with swirl dominated flow;
4-Cell zone conditions- Operating conditions- I checked on specified operating density;
4-The inlet is a velocity inlet . The water is entering at 11m/s and the air is entering at 4m/s ( I got these data from the table of operational conditions, given the volumetric flow rates of gas and liquid). The outlets are both pressure outlets;
5-For solution methods I used a coupled scheme, for pressure PRESTO, for momentum and turbulence equations third order MUSCL;
6- I performed an hybrid initialization in 15 iterations and then I ran the calculation ( steady state, gravity) but in a 1000 iterations the calculation stopped and I didn't have convergence. Furthermore during the iterations it kept popping up this warning message: turbulent viscosity limited to viscosity ratio of 1.000000e+05. In the following image there are my residuals.

I also tried with the Eulerian multiphase model, keeping all the others settings:
in this case I don't have the warning message but the residuals still don't converge.

I don't have experience with ansys, I am just a beginner so I could really use some help.

[LauraOsorio]

Originally Posted by Cheza16

Hi everyone,
I am new on the forum and I am a beginner with ansys.
For my master degree thesis I have to simulate the separation of mixed air and water within a GLCC separator.
In the following image there are the operational conditions and the dimensions of my separator.
I have drawn my cyclone model on spaceclaim and imported it onto ANSYS, I am looking for guidance for what parameters I should set along with boundary conditions.
I have already tried to perform some simulations (steady state) but I can't manage to have convergence.
These are the steps I followed:
1-I kept the mesh the simplest as possible -with 10 inflation layers- in order to have a quicker solution ;
2-I have chosen a mixture multiphase model (double precision checked), with phase1 being water ( Volume fraction 0.7) and phase2 being air -but I am not sure I am doing this correctly;
3-I have chosen a Viscous k-epsilon model, RNG with swirl dominated flow;
4-Cell zone conditions- Operating conditions- I checked on specified operating density;
4-The inlet is a velocity inlet . The water is entering at 11m/s and the air is entering at 4m/s ( I got these data from the table of operational conditions, given the volumetric flow rates of gas and liquid). The outlets are both pressure outlets;
5-For solution methods I used a coupled scheme, for pressure PRESTO, for momentum and turbulence equations third order MUSCL;
6- I performed an hybrid initialization in 15 iterations and then I ran the calculation ( steady state, gravity) but in a 1000 iterations the calculation stopped and I didn't have convergence. Furthermore during the iterations it kept popping up this warning message: turbulent viscosity limited to viscosity ratio of 1.000000e+05. In the following image there are my residuals.

I also tried with the Eulerian multiphase model, keeping all the others settings:
in this case I don't have the warning message but the residuals still don't converge.

I don't have experience with ansys, I am just a beginner so I could really use some help.

Hello, I am simulating a similar problem. I would like to know if you could share your thesis with me or if I can find it online.