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

Intake-Fan BC/velocity to pressure jump correlation

Register Blogs Community New Posts Updated Threads Search

Like Tree1Likes
  • 1 Post By LuckyTran

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 19, 2019, 22:59
Default Intake-Fan BC/velocity to pressure jump correlation
  #1
New Member
 
ahmad
Join Date: Mar 2018
Posts: 21
Rep Power: 8
ahmad_xjtu is on a distinguished road
Hi all,
I am trying to find heat losses from a flat plate. The plate is located 1m away from the fans as shown in the picture below. The wind velocity at fans exit is 3m/s. However, I don't know how to input the velocity in terms of pressure jump.
Any help/reference/ book would be highly appreciated.

Thank you
Attached Images
File Type: jpg fan-velocity.jpg (52.2 KB, 68 views)
ahmad_xjtu is offline   Reply With Quote

Old   March 20, 2019, 00:57
Default
  #2
Member
 
gartz89's Avatar
 
Angel Penev
Join Date: Apr 2016
Location: Bulgaria
Posts: 47
Rep Power: 10
gartz89 is on a distinguished road
There is an option for define the polynomial function of normal velocity and static pressure, but unfortunately you have to know the characteristic of the system and I'm not quite sure, but that is not very easy way.
gartz89 is offline   Reply With Quote

Old   March 20, 2019, 02:48
Default
  #3
New Member
 
ahmad
Join Date: Mar 2018
Posts: 21
Rep Power: 8
ahmad_xjtu is on a distinguished road
thank you for your response
I have checked the option but I don't have required parameters. The only known parameter is velocity. If you come across any tutorial please share. I am searching for the same as well.

thanks again.
ahmad_xjtu is offline   Reply With Quote

Old   March 20, 2019, 09:32
Default
  #4
Senior Member
 
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,754
Rep Power: 66
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
You need the fan curve. It is a performance spec of the fan. Ask the manufacturer of the fan for this curve.

All fans have a rated volumetric flowrate (usually in CFM if you are in the US) and a pressure head.

You can also crudely backcalculate this pressure head if you know the flowrate (from velocity) and power input needed to run the fan (Wattage). The Wattage either goes into doing work on the air or is dissipated into heat. Electric motors are quite efficient and don't produce that much heat relative to the flow work that the fan does. The pumping power is equal to the volumetric flowrate (velocity x area) multiplied by the static pressure rise.
LuckyTran is offline   Reply With Quote

Old   March 20, 2019, 11:44
Default
  #5
Member
 
gartz89's Avatar
 
Angel Penev
Join Date: Apr 2016
Location: Bulgaria
Posts: 47
Rep Power: 10
gartz89 is on a distinguished road
Ok but I'm wondering when we know this air - ventilator curve for
(velocity x flow area) and the static pressure how can we define this curve in fluent. For example I've got experimental data and I've got many measure points for pressure and mass flow. If I want to validation this experiment with the simulation, then fluent gives me absurd results. My question is when I've got these parameteres where can I set them, because the pressure and velocity is quite independent. Regards!
gartz89 is offline   Reply With Quote

Old   March 20, 2019, 14:34
Default
  #6
Senior Member
 
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,754
Rep Power: 66
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
It's in the Fan boundary conditions settings. It should be pretty obvious how to get there if you have Fluent open. Just choose the fan type and click edit.
gartz89 likes this.
LuckyTran is offline   Reply With Quote

Old   March 20, 2019, 22:23
Default
  #7
New Member
 
ahmad
Join Date: Mar 2018
Posts: 21
Rep Power: 8
ahmad_xjtu is on a distinguished road
Thanks guys.
Thanks Luckytran. got it. Thanks for time and effort. I hope I will get it solved now.

Cheers,
ahmad_xjtu is offline   Reply With Quote

Old   March 22, 2019, 07:17
Default
  #8
Member
 
gartz89's Avatar
 
Angel Penev
Join Date: Apr 2016
Location: Bulgaria
Posts: 47
Rep Power: 10
gartz89 is on a distinguished road
Sorry for disturb you again, but If I define the Fan boundary condition like a interior, after that I define my curve like a polynomial function and solve the problem... and how ansys determinate the balance between losses in the system and this fan curve. Could you explain this, because if I change my interior like a only fan I don't know how to set the losses in the system. Regards!
gartz89 is offline   Reply With Quote

Reply

Tags
fan-intake, pressure jump


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
UDF pressure jump over a fan Bell X Fluent UDF and Scheme Programming 1 April 13, 2015 05:05
fan pressure comparison Aadhavan Main CFD Forum 0 February 21, 2015 07:50
negative or positive pressure jump at exhaust fan Selo melo FLUENT 2 March 28, 2007 23:23
Gas pressure question Dan Moskal Main CFD Forum 0 October 24, 2002 23:02
Hydrostatic pressure in 2-phase flow modeling (long) DS & HB Main CFD Forum 0 January 8, 2000 16:00


All times are GMT -4. The time now is 03:00.