Basic Heat Transfer Question

[jakvett]

Let me start by saying that I have not taken heat transfer yet. My question seems like it should be very basic, but I just don't know which equation to use.

I have a heat source that is 500 degrees F. If I have a heat shield at some distance away from the heat source, with air separating the two. How hot will the heat shield be?

What properties do I need to know in order to solve? Basically, I'm looking for an equation to apply to this problem. Thanks in advance!

 

[CH5OH]

try wiki convection,conduction,radiation

 

[IRstuff]

There is no equation like that. However, there are other equations for: convection, conduction, and radiation that can be combined to get what you want. Note that this will require a solver or iteration, since the answer will not be in closed-form.

TTFN

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[jakvett]

Okay. That's what I needed to know. Thanks.

 

[vpl]

Was this a homework question?

Patricia Lougheed

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[dvd]

Heat shields are discussed in Thermal Radiation Heat Transfer by Siegel and Howell. You need to understand heat transfer to solve...

 

[willard3]

Guarantee it was homework.

 

[jakvett]

Not homework. I have diesel particulate filter that sits outside a machine. It regenerates at 480 F. I need a heat shield that that brings that temperature down to something acceptable so the operator doesn't have a potential for getting burnt. I generalized the question.

 

[IRstuff]

Then, you'll need more than just a heat shield; you'll probably need a a cooling fan, and a grillwork, rather than a solid sheet shield.

TTFN

FAQ731-376
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[jakvett]

Interesting. Can you estimate how hot just a heat shield would get?

 

[vpl]

You might want to do a search on the term "heat shield" in these forums.

Here's one thread to get you started: thread391-305369.

Patricia Lougheed

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[MiketheEngineer]

Build one. Go to Radio Shack or Grainger and buy an infrared thermometer for about $70. Test it and go from there.

Cheaper than spending hours working out equations which will probably not give you the right answer anyway!!

Don't forget that ambient temperature, humidity and wind will play a BIG role....

 

[jakvett]

I have a thermal imaging camera at my disposal. I know I could test it, but I was hoping it would be simpler to crunch numbers. As was stated, I haven't taken heat transfer yet, and it sound like it's not a straight forward answer so maybe testing is the best solution.