CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > Siemens > STAR-CCM+

The difference between Heat Transfer Coefficient and the local one.

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   February 25, 2012, 07:20
Default The difference between Heat Transfer Coefficient and the local one.
  #1
Senior Member
 
Join Date: Dec 2011
Posts: 121
Rep Power: 15
fshak92 is on a distinguished road
I wonder if anyone can explain the differences between the HTC and the LocalHTC.

I think the HTC in each mesh cell, is calculated by :
dividing the heat transfer of that point
by
the temperature differences of that point and a reference temperature(which can be changed in the field function).
Am i right?
but what about the LocalHTC?
because the local of a value is the integral of that value and in our case it should be integral value on our surface.but why it does not need any reference temperature?

Can anyone explain about these concepts and the way StarCCM calculates them.

Thanks in advance.
fshak92 is offline   Reply With Quote

Old   February 26, 2012, 16:49
Default
  #2
Senior Member
 
Ryne Whitehill
Join Date: Aug 2009
Posts: 312
Rep Power: 19
rwryne is on a distinguished road
Quote:
Originally Posted by omid88 View Post
I wonder if anyone can explain the differences between the HTC and the LocalHTC.

I think the HTC in each mesh cell, is calculated by :
dividing the heat transfer of that point
by
the temperature differences of that point and a reference temperature(which can be changed in the field function).
Am i right?
but what about the LocalHTC?
because the local of a value is the integral of that value and in our case it should be integral value on our surface.but why it does not need any reference temperature?

Can anyone explain about these concepts and the way StarCCM calculates them.

Thanks in advance.
I don't have STAR-CCM+ infront of me, so I cannot be definitive but I believe the LocalHTC uses the temperature nearest to the wall to calculate the HTC, rather than a reference temperature.
rwryne is offline   Reply With Quote

Old   February 27, 2012, 12:19
Default
  #3
Senior Member
 
Ryne Whitehill
Join Date: Aug 2009
Posts: 312
Rep Power: 19
rwryne is on a distinguished road
Quote:
Originally Posted by omid88 View Post
I wonder if anyone can explain the differences between the HTC and the LocalHTC.

I think the HTC in each mesh cell, is calculated by :
dividing the heat transfer of that point
by
the temperature differences of that point and a reference temperature(which can be changed in the field function).
Am i right?
but what about the LocalHTC?
because the local of a value is the integral of that value and in our case it should be integral value on our surface.but why it does not need any reference temperature?

Can anyone explain about these concepts and the way StarCCM calculates them.

Thanks in advance.
After looking in STAR:

Just plot the Local Heat Transfer Reference Temperature to see which temperature it is using for this calculation. The formula it is using is found in the help file (under "What Methods Are Available for Exchanging Heat Transfer Coefficients?")
rwryne is offline   Reply With Quote

Old   March 12, 2012, 09:15
Default
  #4
Senior Member
 
Join Date: Dec 2011
Posts: 121
Rep Power: 15
fshak92 is on a distinguished road
Quote:
Originally Posted by rwryne View Post
After looking in STAR:

Just plot the Local Heat Transfer Reference Temperature to see which temperature it is using for this calculation. The formula it is using is found in the help file (under "What Methods Are Available for Exchanging Heat Transfer Coefficients?")
Thank you for the answer.

I set a same temperature for both the wall temperature around my body and also the reference temperature but the local heat transfer coefficient are 1000times more than the heat transfer coefficient.
Unfortunately the tuturial of the software has not explained the difference in a good way.

Last edited by fshak92; March 13, 2012 at 05:19.
fshak92 is offline   Reply With Quote

Reply

Tags
htc, lhtc


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



All times are GMT -4. The time now is 02:59.