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

Total Heat Flux Calculated by FLUENT

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 7, 2006, 19:53
Default Total Heat Flux Calculated by FLUENT
  #1
Darron
Guest
 
Posts: n/a
Users,

wanted: how to access the total heat flux, as calculated by FLUENT, from within a UDF.

context: I have a very simple rectangular (2d) enclosure- 4 walls. I've imposed constant temperatures to three of the sides and a linearly varying temperature along the 4th wall. I'm using the S2S radiation model, and this problem is radiation only- no flow. The walls are of "0" thickness and the enclosure is just air. I want the total heat flux at each cell/face, of the wall across from the one with varying temperature. I know Fluent can calculate the heat flux (you can plot it! or use "Wall Fluxes"), but I don't know how to get to it from within my UDF - is there a way to read it in or calculate it? Another way of calculating it using other vari ables determined by FLUENT? Thank you!
  Reply With Quote

Old   August 9, 2006, 11:32
Default Re: Total Heat Flux Calculated by FLUENT
  #2
Daniele Scatolini
Guest
 
Posts: n/a
for each wall zone, within a f_loop,do this: co=F_C0(f,t); /*see udf manual*/ tco=THREAD_T0(t); temp_face=F_T(f,t); temp_centroid=C_T(co,tco); BOUNDARY_FACE_GEOMETRY(f,t,A,ds,es,A_by_es,dr0);/*see manual*/ q=C_K_L(co,tco)*(temp_centroid-temp_face)/ds; /*that is q=lambda*DT/ds !*/
  Reply With Quote

Old   August 9, 2006, 11:38
Default Re: Total Heat Flux Calculated by FLUENT
  #3
Daniele Scatolini
Guest
 
Posts: n/a
Don't you know how i was surprised by the fact that fluent can plot the heat flux but doesn't have a simple macro that works for each cell/face as i did! Moreover,i tested my way to compute heat flux, summing it all over the faces of a wall,and comparing it to the fluent's plot: perfect. Please, if you know how to, ask fluent inc. to enclose a similar macro in the next release! Cheers from Roma.
  Reply With Quote

Old   August 17, 2006, 14:31
Default Re: Total Heat Flux Calculated by FLUENT
  #4
Darron
Guest
 
Posts: n/a
Thank you Daniele. I just found a different way- good news! FLUENT does have a hidden macro for heat flux (I don't know how anyone is supposed to figure this out- I got it through a tech support search). You can use the macro "BOUNDARY_HEAT_FLUX(f,t)" to return the total (convection, radiation, conduction) heat flux for a given face. This is flux per area, so multiply that value by the boundary's area if you want the total heat flux. I worked great in my simple model. So hopfully this macro will show up in the next eddition of the FLUENT UDF manual! --Darron
  Reply With Quote

Old   June 1, 2010, 08:46
Default
  #5
New Member
 
Join Date: Mar 2010
Posts: 3
Rep Power: 16
Darth Sander is on a distinguished road
Hi Darron, I have the same problem...can you tell me where is this tuttorial/tech support or send me a copy or a link? Is it possible use the MACRO BOUNDARY_HEAT_FLUX with a dynamic mesh? Thank you very much...
Bye
Darth Sander is offline   Reply With Quote

Old   November 16, 2010, 22:17
Default
  #6
New Member
 
tan Xianghui
Join Date: Nov 2010
Posts: 3
Rep Power: 16
andred is on a distinguished road
Would you please tell us more exactly of how to use the macro
andred 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
Wall Heat Flux & Temperature Greg Perkins FLUENT 10 November 20, 2015 10:32
Change Equation Total heat flux ? boku FLUENT 0 November 24, 2010 04:00
HTC/Wall Heat Flux monitoring in 12.1 Michael.J CFX 4 June 10, 2010 09:36
Inconsistent Total Heat Transfer Rate Ken Adams FLUENT 0 July 24, 2007 12:04
solar heat flux through roof Tim FLUENT 1 January 17, 2007 17:01


All times are GMT -4. The time now is 11:51.