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

Server Rack in a room

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   July 19, 2009, 21:45
Default Server Rack in a room
  #1
New Member
 
Jayantha Siriwardana
Join Date: Jul 2009
Posts: 3
Rep Power: 17
jayantha is on a distinguished road
Hi everybody.
I am trying to simulate airflow inside a room with following conditions
1. I have a rack of servers which have air inlets and air outlets. Air inlets draw cold air into the rack and air outlets dissipate hot air to the room.
2. The room has one air conditioner.

So far I have done the following in CFX.
I Created a room with air conditioner based on the HVAC simulation tutorial.
Next I imported the mesh for the rack separately created and tried a few options to define the air flow through the rack.
1. First thing I did was to define the rack in the solid domain as in another thread which tried to simulate humans inside a room. But with that option I cannot define the air flow through the rack because it doesn't allow to define inlets and outlets. Without defining air inlets and outlets, the simulation works fine.
2. Next thing I did was to define the rack in the fluid domain and define wall boundaries for outer surface. This case I can define air inlets and outlets. But the problem arises then I try to run the simulation. It ends with isolated fluid regions error.

Does anybody have a suggestion to get through here?

Thanks in advance.
jayantha is offline   Reply With Quote

Old   July 20, 2009, 03:14
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,871
Rep Power: 144
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
Hi,

Have you considered modelling the fans and heat source as a source point rather than inlets and outlet? This is the normal way of doing this type of thing. Read the documentation and search the forum for source terms.

Glenn Horrocks
ghorrocks is offline   Reply With Quote

Old   July 20, 2009, 03:25
Default
  #3
New Member
 
Jayantha Siriwardana
Join Date: Jul 2009
Posts: 3
Rep Power: 17
jayantha is on a distinguished road
Hi Glenn

I am new to this CFD modelling. I was thinking of modelling the heat dissipation as a radiation flux emitting from the rack outlet.

I will look into your point too.

Thanks.
jayantha is offline   Reply With Quote

Old   July 20, 2009, 19:43
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,871
Rep Power: 144
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
Hi,

Obviously you should model the heat fluxes as they physically exist. The heat load coming out of a computer in a rack will be convective, not radiative so if you use a radiative heat source you will get incorrect results.

Having said that, radiation may or may not be significant in general for your simulation. For HVAC flows it depends on the exact situation as to whether radiation is significant. You will have to work that out.

Glenn Horrocks
ghorrocks is offline   Reply With Quote

Reply


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
HVAC Modeling Humans in Room LilBort CFX 27 July 31, 2009 12:08
Cluster Linux+OpenMOSIX with STAR-CD CFD_User Siemens 9 July 22, 2008 05:52
heat transfer: air in a room and water in a coil Alberto CFX 2 May 9, 2006 10:56
Contaminant Distribution in Air-con Room Jules Main CFD Forum 0 June 13, 2002 11:55
CFD Online Server Load Jonas Larsson Main CFD Forum 0 March 13, 2001 15:29


All times are GMT -4. The time now is 15:46.