Learning Forum

[uk101]

Hello,

I will be doing multi-phase (water-air) simulations for a Venturi geometry with the permanent holes on the throat open to atmospheric pressure. Can i choose two models for my simulation (e.g DPM and Euler-Euler (Mixture) model) ? Since, there will be bubbly flow regime due to open vents and after throat turbulences.

Moreover, i am not sure about the volume fraction of the second phase (air, coming from side vents), so it will be better if something is recommended considering it as well.

 

P.S: dia for the vents would be around 1 -2 mm

Any help would be really appreciated

[Rob]

What are you trying to find out?

[uk101]

I want to run multi-phase simulation for my optimized pressure recovery backflow prevention device, which is a venturi with X-diffuser angle, Y-Converging angle and Z throat length. At the throat two vents (holes with some dia) that are open to atmosphere, are provided, so that water flows out of it in case of backflow and contamination can be avoided.

"What am i trying to do is "   ..... I want to investigate the functionality of my design, whether it is working properly or not, secondly the pressure drop is minimized or not. To propose the proper design for the pressure recovery.

Thats why i want to go as precise as i can about the cavitation, bubbly flow and all the other regimes at the downstream. For that reason i thought to be using a hybrid model if its possible or not. Or if there any other suggestions exist.

 

Thanks.

[DrAmine]

You can go for DPM if volume fraction of air is not very high. DPM is only coupled with primary phase in case you want to account for two-way effects. You can deal all that within Eulerian Multiphase Model where you get started by Mixture model with three phases. Here you need to know the volume fraction of air coming from the sides.If only air is coming from there than simpe set it to one. That is your input.

 

[uk101]

Thanks Amine

 

[uk101]

Mixture model with three phases? can you please explain. I thought that the main inlet would be given material as water and phase as water-liquid and the other two inlets (vents) will be given air. is it so?

[DrAmine]

Yes. But you mentioned cavitation so that is why three phases. But you can at first ignore that.

[uk101]

@abenhadj, Thanks alot

[DrAmine]

Please mark this then as "Is solved"