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

Mystery led heat transfer POWER LED

Mystery led heat transfer POWER LED

Mystery led heat transfer POWER LED

hi everyone
i made a test, i assembled two different type LED (citizen/cree) on the same heat sink, the power of the LED is same (36W) but in the first case i got a temperature (TC) of 70 °c in the second case i got 90 °c....so what the reason of this gap?
how can control this behaviour during the cfd analysis?


RE: Mystery led heat transfer POWER LED

Change one model so that it becomes the other and see which change caused the difference.

Why do you want a reason for the temperature difference? Do you think one result is wrong or that they should be less different (how much less)? I guess temperature in an LED depends strongly on the thermal resistance of it's internal parts, which might be different for each one.

RE: Mystery led heat transfer POWER LED

during my analysis i assign the power (heat genereted) to the led, the material of the heat sink etc etc but i am wondering wich is the factor that i must assign to identify two different kind of led that have different thermal resistance?

RE: Mystery led heat transfer POWER LED

i tought in this field we could discuss about the cfd analisys for the led thermal behaviur

RE: Mystery led heat transfer POWER LED

I don't clearly understand your question, but maybe this helps?

To model different thermal resistances, you could put an artificial resistive layer between the LED and the heatsink. Then tune that material's thermal conductivity to give the total thermal resistance you want. That's if you can't model the LED accurately with its actual material properties. Don't forget contact resistance of the interfaces between heatsink and LED, and any other contacting parts in the heat path. All these factors would affect the temperature of the part generating the heat.

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! Already a Member? Login


White Paper - How ESI is Helping Move New Medical Device Product to Market Quicker & More Cost Effic
Early Supplier Involvement has long been a strategy employed by manufacturers to produce innovative products. Now, it almost seems like a necessity. Because decisions made in the design phase can positively affect product quality and costs, this can help add value to OEM bottom lines. This white paper will discuss many facets of ESI, including why it’s so valuable today, what challenges limit the benefits of ESI, how cost is impacted, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close