[kasto89]

Hi all, I really need a super urgent help because i am going crazy and I hope someone could help me.
I need to solve the system in the attached picture.
Attachment 55031
We have 3 inlet side and 1 outlet in the upper side. (they are 3 heating exchanger assembled like in the picture, and a suction fan in the top, but I dont need to solve it, I only need to simulate the flow in the box).

I want to understand if the 3 inlets have the same flows or not (i suppose the inlet2 is favorite). So I want to implement a pressure driven flow, imposing the same pressure (for example 150Pa) in the inlets and 0 to the outlet. I tried it, but obiouvsly I have no convergence, bcs I used zeroGradient on all sides for velocity.
Can you please let me know how to set in detail boundary for pressure and velocity and maybe also for k and epsilon for this case?
Do you have some links for a pressure driven INCOMPRESSIBLE guide? I didnt find anything useful.
Thanks

Best Regards
Fabrizio

[piu58]

Pressure only b.c. are sometimes hard to manage. I recommend to set the pressure gradient to zero at the outlet. You may look in the solution files where it falls and may correct your inlet values if necessary.

[kasto89]

Hi, thanks for your reply. I really tried all possible configuration for boundary. But please, be more clear : if i use zerogradient for pressure at outlet I should set the velocity at outlet and the pressure at inlet, correct?

[arjun]

The whole top is outlet or the outlet is at the center?

[piu58]

> if i use zerogradient for pressure at outlet I should set the velocity at outlet and the pressure at inlet, correct?

Yes, that should fit your problem. You'll see how the flow divides between the three inlets.

[kasto89]

Hi,

the whole top is the outlet. There is a sucting fan in the top (but I didnt make the mesh on it), so I want impose the static pressure at inlet to simulate the fan.

thanks