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Old   July 30, 2003, 16:30
Default FLOW RATE PROBLEM
  #1
Dario Rigaud
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Hi, I need some info:

How can I simulate a raise of presure between the two sides of a surface that perfectly slices a domain or the normal velocity in that surface witout building another domain.

Thanks u very much
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Old   July 30, 2003, 16:35
Default Re: FLOW RATE PROBLEM
  #2
Schmidt
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Hello Dario,

I think you can do it using a mass surce or defining a traslating frame, I'm not relly sure but yu ca try using meshing controls that allows you to fix the cartesian velocity of the pressure raise at the specific surface.

I Hope that Help You.

I'm not so sure
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Old   July 31, 2003, 09:09
Default Please, Can anybody help me? I'm in trouble.
  #3
Dario Rigaud
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Please I need a coherent answer:

It seems that smith doesn't want to help me, he's trying to confuse me, please if you know the solution please post it.

I really need thatr answer.

Thank y'all
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Old   July 31, 2003, 12:12
Default What's the problem with you?
  #4
Schmidt
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I was only trying to help you and you just said that about me!

Is there somebody that can help this guy?
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Old   July 31, 2003, 14:05
Default Re: What's the problem with you?
  #5
Tanya
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Hello

Im Tanya n' I've just started working at Carrier corp. I'm giving my first steps with CFX and I've a similar problem.

I like to help people in trouble but i'm so sorry Dario, I don't have an Answer.

This forum is suposed to be serious and we come here in order to exchange info, so please, let's make it happen!!!
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Old   July 31, 2003, 17:16
Default Re: Please, Can anybody help me? I'm in trouble.
  #6
Neale
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Your original question is not clear to me at all, hence I cannot help you. Perhaps you can clarify:

1. What is the physical problem you are trying to solve? 2. What sort of models do you want to use for it? 3. What sort of boundary conditions do you need to use?

etc...

Neale
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Old   July 31, 2003, 17:39
Default Here's my problem, I'LL EXPLAIN BETTER, Thank you!
  #7
Dario_Rigaud
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My problem is simple:

I have two rooms with certain geometry, each one have an opening in its boundaries.

These two rooms are conected by a cylindrical duct in which is installed a ventilator.

The ventilator is not kown, but the flow rate that it have to move is known.

I need to calculate the pressure of that ventilator, the difference of pressure between the two sides of this equipment, in order to select the model and the motor.

I'm thinking about using BC's at the openigs of the rooms of the type "opening" with relative pressure of zero.

I need to know how can I set a condition that fix the flow rate in the duct and make the program to calculate the pressure when the air is flowing in steady-state for the resistance that the geometry of these rooms offers to the flow.

I really appreciate if you can help me out

Thanks a lot!

Dario Rigaud
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Old   August 1, 2003, 08:02
Default Re: Here's my problem, I'LL EXPLAIN BETTER, Thank
  #8
vince
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I'm not sure that I have well understand your problem. But why do you want to use a opening for your first room. At your place, I would have use a inlet: You know the inlet surface, your mass, so you can impose a velocity. Or else you can also impose a mass flow rate I think. For the BC of the second room, if you have no recirculation, use an outlet with a zero pressure. Your duct being between the two chamber should normally see the same gas flow rate.
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Old   August 1, 2003, 08:15
Default Re: Here's my problem, I'LL EXPLAIN BETTER, Thank
  #9
Dario_Rigaud
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Thanks Vince

That's right, I can set a BC's a the inlet but the drop of pressure will happen throught both rooms and in the cylindrical duct the pressure will remains aproximately constant.

I need to put a conditon at the duct that make the fluid flows at a known rate making suction t the first room and inyecting in the second room.

Thanks a lot!

D.R.
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Old   August 1, 2003, 10:16
Default >
  #10
Dario_Rigaud
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I need to put a conditon at the duct that connect these two chambers that make the fluid flows at a known rate making suction to the first room and inyecting in the second room.

Thanks a lot!

D.R.

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Old   August 5, 2003, 04:56
Default Re: >
  #11
Bob
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You could set up a subdomain and apply a momentum source, that should give you the desired flow rate. The modifications to the model wouldn't be too drastic. If you didn't want to modify the model you could position the momentum source using CEL and a step function. Bob
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