×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Net heat flow not same as total heat flux

Net heat flow not same as total heat flux

Net heat flow not same as total heat flux

(OP)
Hi I'm not totally familiar with ANSYS. I want to find a way to compute the net (total) heat flow rather than the discrete steps of heat flow that match a mesh.

In the example a copper rod has a constant temp. applied  at each end (200C one end and 93C at other).  Convection heat transfer coeff. is known and so is the ambient temp.
Calculating; one can integrate the heat flux along the surface to arrive at a total Watts of heat loss.

How does one derive this figure by modelling?

One has Watts/m2 for discrete elements ... The attached jpg shows the current stage of the model.
Thanks dazed

RE: Net heat flow not same as total heat flux

(OP)
I think it is the Reaction Probe function selecting the appropriate surface and the convection boundary condition.
2thumbsup

RE: Net heat flow not same as total heat flux

Interestingly enough, I'm dealing with a similar problem in Workbench. The reaction probe is the appropriate means of outputting net heat crossing a convective or temperature boundary.

Unfortunately, I don't think that it is possible to output the net heat crossing a conductive (contact or continuously meshed surface) boundary in Workbench. This may be possible with APDL scripting and command objects as well, but my APDL skills are limited so I use a different approach.

What I've done is output the nodal flux components along the desired boundary, taken the dot product of the heat flux vectors and the vectors the surface normals, and computed the surface integral in Matlab. It's not the prettiest methodology, but it should get you an answer.

From the look of your model, you might be okay using the reaction probe in the GUI, but if you need the heat passing through a conductive boundary post-processing or APDL scripting might be necessary.

RE: Net heat flow not same as total heat flux

(OP)
Thanks flash3780 - I was thinking of an approach along those lines. Don't have nor am I familiar with Matlab - maybe I need to...

RE: Net heat flow not same as total heat flux

These days I use Octave instead of Matlab. Octave has most of the functionality of Matlab, but is available for free from the GNU project. I've found that it runs best on Linux, but is available for Windoze as well.

RE: Net heat flow not same as total heat flux

(OP)
Thanks for that suggestion! Very kind of you to share that tip!

I will look for that.

Cheers!  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources