need help on heat transfer 1

[teja333]

Consider 800A current is flowing in a copper rectangular bar with known dimensions.Rectangular bar is placed inside a steel cube of known dimensions.The ambient temperature of air is 300K. Now How to calculate surface temperature of bar, Air temperature at different nodes in an enclosure,Inside wall temperature of enclosure and outside wall temperature of enclosure in transient conditions

 

[IRstuff]

Find an FEA program

Is this for school? Student posting is not allowed.

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[dvd]

These kind of questions wouldn't get asked if there was a waiting period between signing up and being allowed to post.

 

[chicopee]

I'll keep quiet on this one. Last time I was lambasted about a comment that I made to an OP when I stated that it was an elementary heat transfer problem.

 

[teja333]

Sorry,If anyone feels bad about the question .Everyone thinks this is a school homework because question asked above looks just simple.Don't think this is simple.If you people think this is basic heat transfer problem why don't you give me solution.Just to calculate surface temperature it took me 5 pages and you think this is very simple.I just want to know if you people know anything about it.

 

[IRstuff]

Didn't say it was simple; hence the suggestion to use an FEA program. This is not a problem that can be easily solved by hand, since you are asking for 3-D temperature distributions. The reason I questioned the question was the wording, since it's cast with "Consider" and a nebulous "rectangular barr" and a nebulous "steel cube." It is just not written as a real-world problem.

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[DRWeig]

Are you also supposed to consider the heating effect of eddy currents in the steel enclosure? In the real world the inductive heating could be rather more severe than a heat transfer problem in your setup.

Best to you,

Goober Dave

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[willard3]

The reason people don't give you a simple answer is because the answer is not simple. You are the only one who thinks this is simple which is what makes everyone think it is a student question. I think the same thing....do your own homework.

 

[MortenA]

or get at FEA solution - by yourself or a consultant

 

[marksummers]

Exactly. Who in industry defines ambient temperature in degrees Kelvin?

 

[IRstuff]

I would imagine that it depends on the specific problem. Absolute kelvins are what are needed to calculate radiation.

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[racookpe1978]

Sorry,If anyone feels bad about the question .Everyone thinks this is a school homework because question asked above looks just simple.Don't think this is simple.If you people think this is basic heat transfer problem why don't you give me solution.Just to calculate surface temperature it took me 5 pages and you think this is very simple.I just want to know if you people know anything about it.

I would, instead, submit that all of the people reading your reply DO know "something about it", and have - in their professional judgement and courtesy, decided that they do not know enough about it to help you accurately without more information. And, they are all humble enough to know they don't know enough about this specific problem to jump in and make potentially fatal assumptions without more information. Their courtesy in asking questions demonstrates not ignorance of the difficulty but awareness of the difficulty of the problem. It also demonstrates each person's willingness to answer to the best of their ability BECAUSE each different person above asked a different question about the original question!

I would recommend you re-consider this attitude with respect to the fee you are (not) paying for other people's time and professional attention to a problem those other professionals are (not) getting paid for. All who have read this problem have tried to help, but all have noted the same thing I did. You have not provided enough information for anybody to begin making judgements about what can be ignored, what is critical, what degree of accuracy is needed, and what can be approximated. In short: yes, the only time all who have read this question have found that little information provided about such critical parameters is when it comes from a homework problem.

If you have found an answer - perhaps not the correct answer! - after five pages of calculations, then congratulations on your possible success. Your effort across those 5 pages confirms that it was - it is! - a difficult problem. If you need someone to check to calculations, then consider the price you are paying some other person to redo five pages of your calculations. If you have specific qualms about your assumptions or simplifications you have made, then YOU need to either pay for the re-check, or provide us the information to evaluate why you made those assumptions and approximations.

 

[EnergyMix]

Well said Rob.

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[teja333]

I am calculating temperature distribution in the fluid between two Vertical plates carrying current(which means there is internal heat generation in the plates) I have got continuty, momentum and energy equations but the equations are without internal heat generation. So can anyone give me required equations (or) is there any method to find temperature distribution manually other than natural convection equations.

 

[teja333]

Sorry for not specifying more details. How can I edit post

 

[IRstuff]

Are you now asking about a different problem?

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