CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

Negative Room Pressure

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 4, 2016, 06:20
Unhappy Negative Room Pressure
  #1
New Member
 
Angel
Join Date: Dec 2016
Posts: 2
Rep Power: 0
Angel-CFD is on a distinguished road
Hi, I'm a student and in my Masterís degree final project i have to simulate a Negative Room Pressure.

In this case, I have 2 rooms:
- An anteroom, where I have to get -2.5 Pa
- The patient room --> -5 Pa

Both rooms are conected by a gap around the door. Both rooms have air difussers (with a ventilation system that removes more exhaust air from the room than air is allowed into the room) and gaps around other doors and windows (boundary condition = pressure inlet 0).

The main problem is that i never get a convergence. I tried to separated the room in three bodies:
- Anteroom
- Patient Room
- Gap door. I made a structured mesh in this body, because i thought the problems were here, but them remain.

So I have no idea what is wrong. I simulate with standard k-e, althought I have tried other methods.

I wonder if the problem is that is no possible to maintain in contact two different pressure, or something like that.

On this aspect, I would like to ask for your help.
Angel-CFD is offline   Reply With Quote

Old   December 4, 2016, 08:16
Default
  #2
Member
 
Quang Le Dang
Join Date: Jun 2012
Posts: 61
Rep Power: 13
SPH_CFD is on a distinguished road
Quote:
Originally Posted by Angel-CFD View Post
Hi, I'm a student and in my Masterís degree final project i have to simulate a Negative Room Pressure.

In this case, I have 2 rooms:
- An anteroom, where I have to get -2.5 Pa
- The patient room --> -5 Pa

Both rooms are conected by a gap around the door. Both rooms have air difussers (with a ventilation system that removes more exhaust air from the room than air is allowed into the room) and gaps around other doors and windows (boundary condition = pressure inlet 0).

The main problem is that i never get a convergence. I tried to separated the room in three bodies:
- Anteroom
- Patient Room
- Gap door. I made a structured mesh in this body, because i thought the problems were here, but them remain.

So I have no idea what is wrong. I simulate with standard k-e, althought I have tried other methods.

I wonder if the problem is that is no possible to maintain in contact two different pressure, or something like that.

On this aspect, I would like to ask for your help.
Really? Pressure is never negative (physically)
SPH_CFD is offline   Reply With Quote

Old   December 4, 2016, 10:14
Default
  #3
New Member
 
Angel
Join Date: Dec 2016
Posts: 2
Rep Power: 0
Angel-CFD is on a distinguished road
When i said negative pressure, i referred to gauge pressure, sorry.
Angel-CFD is offline   Reply With Quote

Old   December 5, 2016, 08:26
Default
  #4
Member
 
Quang Le Dang
Join Date: Jun 2012
Posts: 61
Rep Power: 13
SPH_CFD is on a distinguished road
Quote:
Originally Posted by Angel-CFD View Post
When i said negative pressure, i referred to gauge pressure, sorry.
So, do you use gauge pressure for simulation? Because in simulation, I always use absolute pressure. Also, check operating condition pressure. And let me know your simulation in details (Boundary condition, mesh, etc).
SPH_CFD is offline   Reply With Quote

Reply

Tags
convergence, divergence, negative pressure, room

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
static vs. total pressure auf dem feld FLUENT 17 February 26, 2016 13:04
sonicFoam - pressure driven pipe: flow continuity violation and waveTransmissive BC Endel OpenFOAM Running, Solving & CFD 3 September 11, 2014 16:29
Negative pressure jcamilleri STAR-CCM+ 1 April 10, 2014 05:27
negative pressure mAx FLUENT 0 January 25, 2006 14:31
what the result is negatif pressure at inlet chong chee nan FLUENT 0 December 29, 2001 05:13


All times are GMT -4. The time now is 22:51.