Heat transfer coefficient

Date 11-30-2010 14:24

THere are quite a few references available from the American Society of Materials (ASM). They are pricey but you should find anything you need there. Just google them and go to their website.

By G.S.Crisi (****)

Date 12-01-2010 17:25

Mohsen,
let me understand exactly what you mean.
If you're talking about the "conductivity coefficient" of stainless steel, i.e., how many watts are transmitted per meter of thickness and degree Celsius of temperature difference (or kilocalories per meter, hour and degrees Celsius; or BTU per foot, hour and degree Farenheit), js55's answer is perfectly correct.
As a matter of fact, you can find that information not only on ASM's handbook but also in a number of engineering manuals, for example Perry's Chemical Engineer's Handbook and Mark & Baumeister's Mechanical Engineer's Handbook.

But the words "heat transfer coefficient" are confusing, at least to me. I've got the impression that you're talking about the heat transfer coefficient across a stainless steel surface that separates a hot fluid on one side form a cold fluid on the other side.
Which is your case?

Giovanni S. Crisi
Sao Paulo - Brazil

By mohsen roshani (*)

Date 12-02-2010 22:27 Edited 12-02-2010 22:34

i better to say thermal conductivity(W/m.K) instead of heat transfer coefficient
thanks for your attention
i just find a constant number but i need it as the function of temperature
gratefully , Mohsen

By G.S.Crisi (****)

Date 12-03-2010 00:32

OK, I've understood.
Just a clarification: the correct English term is "thermal conductivity". "Conductivity coefficient", that I used, is the litteral translation of the Portuguese term "coeficiente de condutividade" that is used in Brazil.
You're also right in that the SI unit of thermal conductivity is watts per meter and per degree Kelvin, not Celsius as I said. From a practical point of view, however, they're exactly the same, because one degree Kelvin of temperature difference is the same as one degree Celsius of temperature difference.

I must agree with you in another thing: engineering manuals like Perry, Mark & Baumeister etc. etc. use to list the thermal conductivity at ambient temperature, and what you need is the thermal conductivity at different temperatures. I'm sorry I can't help you. I would say, however, that on the ASM manuals, as js55 suggested, you'll find a lot of information.
Giovanni S. Crisi

By rlitman (***)

Date 12-03-2010 01:06 Edited 12-03-2010 01:35

There is a chart across a wide range of temperatures of thermal conductivity of selected metals in my copy of the CRC Handbook of Chemistry and Physics, but it is only for elemental metals, so while it includes iron, it does not include stainless steel.

Edited:
That chart referenced "NSRDS-NBS 8", which can be found here:
http://www.nist.gov/data/nsrds/NSRDS-NBS-8.pdf
While that report does not include stainless steel, it does have some very nice graphs showing how thermal conductivity of metals vary with temperature, and in a pinch, it looks like you could use the slope from that graph to estimate the variance along a reasonable range of temperatures, as above cryogenic temperatures, the graph appears rather linear. Even if you cannot derive useful information from the data, it is good reading to understand how the data was collected, and where the variance comes from.

Although I don't have access to this, you may be able to find at a better library:
"New measurements on thermal conductivity reference materials" by Powell, R. W., and Tye, R. P, in the International Journal of HEat and Mass Transfer, Volume 10, Issue 5, May 1967, Pages 581-596
It looks like that may have what you want.

This document includes a range of temperatures studied for 304L stainless too:
http://symp15.nist.gov/pdf/p713.pdf