[piyushchauhan94]

Hello all,

I am working on the simulation of a 2L photobioreactor. The PBR has dimensions of 50cm X 22.5cm X 2cm. It uses a sparger for maintaining the flow which includes a pipe with 13 holes (d=0.4mm) through it and the air inlet is located at the side. The geometry is shown in the pics attached.

The inner diameter of sparger pipe is 6mm and the outer diameter is 7mm. The depth of the dividing plate shown is 1.6cm.
The blue face is drawn temporarily to depict the level of water. The part above it is empty.

Since I'm new to cfd softwares, I don't know how to mesh this geometry properly. Kindly guide me how to partition this geometry and then mesh it using a scheme which would be best for simulating the flow in such a case.

Thanks in advance

[-mAx-]

*did you extract the fluid volume?
*I would start to isolate the sparger holes by splitting your domain with outer surface of thbe, and then inner surface of tube. Doing that all the sparger holes should appear as volume.
Then mesh those volumes with hexa with enough cells in the diameter

[piyushchauhan94]

Thank you for your reply

I have meshed the sparger pipe and the sparger holes and it turned out to be fine.

The fluid volume that I have defined is the entire shell minus the vertical dividing plate(of negligible thickness) minus the entire sparger pipe(including the sparger holes).

Now I want to further divide this obtained volume into two parts near the blue face, the part above being the gaseous phase and the part below being the multiphase. But I'm not sure if defining this blue face is the right way of doing it.

Plus the second multiphase portion has a geometry too complex to be directly meshed. So how should I mesh this by breaking into parts and which meshing scheme would be most appropriate ?

[-mAx-]

Regarding the split along your blue surface, you will have to do it at the end for defining a separate fluid domain (multiphase).

As you mentionned you have a "complex" geometry and you will not be able to mesh it on the fly.
You will have to subdivise it into smaller and basic subdomains.
You already started to do it by isolating the sparger pipe and sparger holes.
Now I would generate another split with a cylinder (coaxial to your tube but with larger diameter)
Doing that you will control the cell transition with tube and rest of domain
Rest of domain could be meshed as hexa