Fan in a Silencer Box Simulation - Boundary Value Problem


#1

I am designing a silencer box for our Antminer and want to simulate the flow and heat transfer in it before I build it.

The miner fans are what drives the air and I need to do the simulation to determine if the air will be drawn in through the bottom chamber and expelled via the top chamber or if there is some form of recirculation between the miner inlet and outlet.

A picture is worth a thousand words, so here are a few showing what I have done so far:

What I have done so far:

I have created a CAD model of the box in Onshape and from the model, I made a part that is the shape of the enclosed fluid volume (see pictures). I created a new project in Onshape and imported the fluid volume part. I then created a mesh which has an issue. I am now busy setting up the simulation and am experiencing a problem defining the boundary conditions.

My problem:

Mesh (minor issue I can try to figure out myself)
As can be seen in the mesh picture, the mesh did not form properly around the miner. I did use a coarse mesh so I will try to run a finer mesh to hopefully solve the issue.

Boundary (the big problem)
The boundary conditions I know, i.e. atmospheric pressure & temperature at the inlet and atmospheric pressure at the outlet is not enough to run the simulation. I know the volume flow rate through the miner and roughly the amount of heat added to the air by the miner but I cannot find a way to include this in the simulation.

Can anyone give me guidelines as to what I should do in order to properly set up the simulation?


#2

Hi @Patrysie!

Very nice project along with a perfect description of your problem, thanks a lot! :+1:

@PowerUsers_CFD and I can have a look at your project and give you some input how you can start this simulation or even optimize it.

All the best!

Jousef


#3

Hi @Patrysie, very interesting!

If you know volume flow rate and heat generated you could model the miner. That is, have an inlet and outlet appropriately placed at the corresponding positions for the miner inlet and outlet. So the atmosphere boundaries could be inlet-outlets and the miner could have a velocity outlet at its inlet (if that makes sense) and a custom velocity inlet at its outlet with a custom temperature definition set to flux heat. This is entirely untested but to me, it makes the most simple setup without actually putting a fan in there.

Let me know what you think,
Darren


#4

Thank you for the quick responses. It’s just before 1am here in SA and I am off to dream land. Will give a proper reply tomorrow evening after work. Hope you guys have a good day!