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

CFX Air conditioning Simulation_expression help!!!! Urgen!!!

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 28, 2009, 06:02
Default CFX Air conditioning Simulation_expression help!!!! Urgen!!!
  #1
New Member
 
yinyin
Join Date: Mar 2009
Posts: 4
Rep Power: 8
yin2 is on a distinguished road
hai,
I am new learner about CFX.
can any one help me to solve my problem? it is quite urgen for me...!!!

I am doing an experiment about the condition of air at an Air conditioning Unit.
Is a DOE (design of experiment) for getting the thermal comfort setting of an Air Conditioning Unit.

So, i need to set the inlet properties at my inlet to get the outlet result for validate by the experiment data.
The result i need is the air velocity, air temperature and the pressure.

do any one know how to write the expression of this condition??

The attachment is the print screen of my problem.
hope anyone can help me!!!

Thanks!!
Attached Files
File Type: doc error.doc (87.0 KB, 23 views)
yin2 is offline   Reply With Quote

Old   March 28, 2009, 22:42
Default
  #2
Senior Member
 
Rikio
Join Date: Mar 2009
Location: SH, China
Posts: 182
Blog Entries: 1
Rep Power: 8
rikio is on a distinguished road
Send a message via Skype™ to rikio
Hi,

Could you describe your problem more detail? What are known from test? and what boundary conditions have you employed? You need to set a nonconstant BC for it such that expression have to be used?
Experimental data of the outlet profile have been obtained, and you have to get a solution by setting inlet properties to match outlet profile?
rikio is offline   Reply With Quote

Old   March 29, 2009, 06:08
Default Re:
  #3
New Member
 
yinyin
Join Date: Mar 2009
Posts: 4
Rep Power: 8
yin2 is on a distinguished road
Hai,
Thanks for reply...

for my experiment, the data i took is the air velocity and air temperature of at the inlet and outlet of the chamber.

So, now i want to do a simulation for comparing the data with my experimental data. got a part is writing the expression for the thermal rountine. That part i not so understand and i feel that the error will occur is cause of that part.

is that really need to write an expression?
or i can ignored it, just done until the boundary condition there?

i set my chamber as adiabatic. set the normal speed of flow for me to set the air flow that i get from my experiment. also the temperature setting. just this two setting i set for inlet. For outlet, i set the pressure as 0 Pa.
yin2 is offline   Reply With Quote

Old   March 29, 2009, 07:47
Default
  #4
Senior Member
 
Rikio
Join Date: Mar 2009
Location: SH, China
Posts: 182
Blog Entries: 1
Rep Power: 8
rikio is on a distinguished road
Send a message via Skype™ to rikio
Hi,

Just set velocity or mass flow at inlet, and pressure at outlet. Of course, other boundary conditions can be used.
Regarding the expression, the temperature is supposed to change in the chamber, right? So you want to define an expression to get the thermal field? Why not giving a heat flux, or something like that, at walls.
rikio is offline   Reply With Quote

Old   March 30, 2009, 06:22
Default Re
  #5
New Member
 
yinyin
Join Date: Mar 2009
Posts: 4
Rep Power: 8
yin2 is on a distinguished road
Thanks rikio,

so, you means that, i can skip the expression part for the setting at the boundary condition there?

so just set the temperature and air speed at inlet, 0Pa at outlet..then just simulate it at solver...

ok, thanks yah...i try it first!!
yin2 is offline   Reply With Quote

Old   March 30, 2009, 08:06
Default
  #6
Member
 
Pratik Mehta
Join Date: Mar 2009
Posts: 32
Rep Power: 8
pratikmehta is on a distinguished road
Hi,

Could you please explain , when you are having the boundary conditions at the inlet , wall and the outlet, what is the expression that you want to insert . Is it to do with the fluid properties dependent on temp , viscosity or some other variables ??,

What is the goal of your simulation ?. apart from it being a DOE


Best of luck
pratikmehta is offline   Reply With Quote

Old   March 30, 2009, 23:34
Default
  #7
New Member
 
yinyin
Join Date: Mar 2009
Posts: 4
Rep Power: 8
yin2 is on a distinguished road
hai,
now i'm doing it without insert any expression. I just set the boundary condition at inlet, outlet and the room (wall of room). Then, the simulation work!!

Since i now ran out of time, so i just try to get the simulation first.
Actually for mine simulation, the expression is needed to get the thermal field, but i ignored it first...
hehe...

my goal of the simulation is to get the temperature profile and velocity profile at the chamber.
yin2 is offline   Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Pros and Cons for CFX, CFdesign, COMSOL Val Main CFD Forum 3 June 10, 2011 02:20
air bubble is disappear increasing time using vof xujjun CFX 9 June 9, 2009 07:59
Air conditioning vipin Gawande CFX 2 November 8, 2007 05:54
TRANSIENT HEAT & BOUYANCY IN CONFINED AIR Carl CFX 1 September 25, 2006 09:48
air conditioning in cars Tadiwos CFX 15 October 18, 2001 13:14


All times are GMT -4. The time now is 15:01.