Author Topic: Thermal conductivity of thermal insulation pads  (Read 719 times)

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Offline FaringdonTopic starter

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Thermal conductivity of thermal insulation pads
« on: November 27, 2022, 11:26:53 am »
Hi
Please advise on the meaning of Thermal conductivity.
The units are Watts per (Metre.Kelvin)

So if Thermal conductivity is 1,  then it means that if a one metre long copper bar of uniform area is in contact with a heat source at one of its ends, then that means that for every 1 watt dissipated, there is a  1 degree reduction in temperature at the other end of the 1 metre bar?

And if its 1000W/(m.K), then that means that for a uniform area copper bar connected at one of a heat source, the source would have to dissipate 1000W to get a 1 kelvin drop across the length of that 1 metre bar?
« Last Edit: November 27, 2022, 11:33:07 am by Faringdon »
'Perfection' is the enemy of 'perfectly satisfactory'
 

Offline jpanhalt

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Re: Thermal conductivity of thermal insulation pads
« Reply #1 on: November 27, 2022, 12:05:01 pm »
Understanding the units is important, and I am one who believes it is particularly important to carry them along during calculations as a check.  Did you bother to look it up for examples?
https://en.wikipedia.org/wiki/Thermal_conductivity#/media/File:Thermal_conductivity.svg

Judging from the plethora of recent posts, I am assuming you have a lot of time on your hands again or are you trying to solve real problems assigned to you by a new employer?
 
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Offline Kean

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Re: Thermal conductivity of thermal insulation pads
« Reply #2 on: November 27, 2022, 09:55:43 pm »
Someone really needs to stop posting on forums and read some engineering books.  That would be me, but even more so the OP.
 
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Offline ConKbot

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Re: Thermal conductivity of thermal insulation pads
« Reply #3 on: November 30, 2022, 01:39:05 pm »
W/(m k) is in a simplified/reduced form that doesn't make intuitive sense. (W m)/(m^2 K) is the full form and is more intuitive, with distance on top, area on the bottom.
 
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Offline Siwastaja

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Re: Thermal conductivity of thermal insulation pads
« Reply #4 on: November 30, 2022, 02:25:17 pm »
If you get the units right without cheating, you got the calculation right, too. I often forget formulas or they are sometimes hard to find from a simple Wikipedia lookup, but units are easier to remember. Work out the formula from the units.

Unit of length is m, and unit of area is m^2, so if you forget on which sides of division they are, resulting unit ends up wrong. Repeat until units are correct, and your temperature difference does not contain 1/m, m or m^2 in it; unit of temperature is just K. Not 1/K, for example!
« Last Edit: November 30, 2022, 02:28:11 pm by Siwastaja »
 
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Offline Mechatrommer

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Re: Thermal conductivity of thermal insulation pads
« Reply #5 on: November 30, 2022, 02:34:31 pm »
recap younger dave...
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 
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Offline FaringdonTopic starter

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Re: Thermal conductivity of thermal insulation pads
« Reply #6 on: November 30, 2022, 06:09:36 pm »
Quote
W/(m k) is in a simplified/reduced form that doesn't make intuitive sense. (W m)/(m^2 K) is the full form and is more intuitive, with distance on top, area on the bottom.
Thanks for this.
Yes, you can see that for every 1 metre you go along a bar of unit area........you loose a Kelvin for every watt at the source end.
'Perfection' is the enemy of 'perfectly satisfactory'
 


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