[minzhang]

Ansys/Fluent/Multiphase

Hello All,

I am using the Eulerian-Eulerian two-fluid model (in Ansys Fluent) to simulate the solid-liquid two-phase flow in a horizontal pipe.
This is the reference paper I am trying to reproduce:
Eulerian-Eulerian Simulation of Particle-Liquid Slurry Flow in Horizontal Pipe
Titus Ntow Ofei and Aidil Yunus Ismail

I want to specify both the mixture velocity (the liquid and solid have the same inlet velocity) and solid volume fraction at the inlet. Initially, I was using "velocity-inlet" but I couldn't define the volume fraction. Then I used "mass-flow-inlet", where the mass flow rate of both liquid and solid phases is calculated based on inlet velocity, solid volume fraction, liquid and solid densities, inlet area, etc.
So I am wondering whether I am doing it right?

Thanks!

[vinerm]

When you use velocity inlet, there is option is choose volume fraction for all the secondary phases under the inlet. This option will appear as a separate tab within velocity inlet option for secondary phase not for primary phase.

[minzhang]

You are right! Thanks!

For the "Velocity inlet" of the solid phase, how to specify the Granular Temperature? I know that the granular temperature is related to the "the mean square of particle velocity fluctuations", but how could I know the "particle velocity fluctuations"?

For the "Turbulence" parameters of the solid phase, if the solid inlet velocity is the same as the liquid phase, these parameters would be the same as the liquid phase, right?

Originally Posted by vinerm

When you use velocity inlet, there is option is choose volume fraction for all the secondary phases under the inlet. This option will appear as a separate tab within velocity inlet option for secondary phase not for primary phase.

[vinerm]

Just like turbulence intensity, you can assume a similar fluctuations since the fluctuations are because of turbulence.

[minzhang]

This is my way:
The main reference is here:
https://www.afs.enea.it/project/nept...ug/node238.htm

I estimated Turbulent Kinetic Energy (k) and Turbulent Dissipation Rate (epsilon), and then I calculated "continuous/liquid phase mean square velocity fluctuations" = 2/3*k. Then, the "solid phase mean square velocity fluctuations" = C^2*"continuous/liquid phase mean square velocity fluctuations", where C is a function of Stokes number (that is the ratio of particle relaxation time and turbulence time).
Finally, the granular temperature = 1/3*"solid phase mean square velocity fluctuations".

Your valuable comments would be greatly appreciated!

In addition, I am wondering whether a small difference of these turbulence related parameters' values will make a difference in the simulation results.

Originally Posted by vinerm

Just like turbulence intensity, you can assume a similar fluctuations since the fluctuations are because of turbulence.

[vinerm]

You are right; a small difference at boundaries won't affect your simulation. So, you can go ahead. The field inside the domain very quickly adjusts to the turbulence field.

[minzhang]

Thank you so much!

Originally Posted by vinerm

You are right; a small difference at boundaries won't affect your simulation. So, you can go ahead. The field inside the domain very quickly adjusts to the turbulence field.