Question on Heat Transfer

Thread Starter

toffee_pie

Joined Oct 31, 2009
212
Hi All,

What is the best way to descibe what i am thinking about? I want to measure the temperature of RTDs - with temperature and map this as the temperature will vary.

If I know what power is driving this heat (lets say 8W for 20s) - or 160Joules.

How can I correlate this to say a material attached to a thermocouple which is measuring the RTDs? Say I am using copper (a good conductor for heat)

the rate of transfer formula > transfer Rate = k•A•(T1 - T2)/d

Copper 398 (W/m/°C)

How can I determine the efficiency of a particular material in delivering the heat transfer ? More energy will create more heat so it is as simple as the higher the transfter rate number the better? or is there more to it?
 

MrAl

Joined Jun 17, 2014
6,514
Hi All,

What is the best way to descibe what i am thinking about? I want to measure the temperature of RTDs - with temperature and map this as the temperature will vary.

If I know what power is driving this heat (lets say 8W for 20s) - or 160Joules.

How can I correlate this to say a material attached to a thermocouple which is measuring the RTDs? Say I am using copper (a good conductor for heat)

the rate of transfer formula > transfer Rate = k•A•(T1 - T2)/d

Copper 398 (W/m/°C)

How can I determine the efficiency of a particular material in delivering the heat transfer ? More energy will create more heat so it is as simple as the higher the transfter rate number the better? or is there more to it?
Hi,

I think you should draw a diagram of what you are doing.
Show each component and the physical dimensions. The dimensions are very important. The better the drawing the better the responses you will get.

Also it depends if the material under test is insulated or not.
 

BR-549

Joined Sep 22, 2013
4,936
toffee_pie.....we don't understand what you are asking. A RTD measures temp. Are you trying to measure a heat flow?

Are you using a simulator?
 

wayneh

Joined Sep 9, 2010
16,102
How can I determine the efficiency of a particular material in delivering the heat transfer ? More energy will create more heat so it is as simple as the higher the transfter rate number the better? or is there more to it?
The k in that formula is where the properties of the material come in. In most cases you can consider k to be constant for a given material within a reasonable temperature range.

Note that the equation is for a steady state heat flux. It sounds like you might be looking at a pulse. That equation is still useful, but you’ll additionally need to consider heat capacity if you’re not at steady state. A large mass of copper for instance will absorb a lot of heat before heat starts to flow out the other side.
 

Thread Starter

toffee_pie

Joined Oct 31, 2009
212
RTDs measure temperature, yes - What I want to do is ensure this temperature is what I expect - if that makes sense. I can use this by using thermocouples which will be attached to the RTDs via conductive copper, I want to see how much energy I can transfer onto a disc and how efficient it would be some other materials, ie some feasibility study.

Not using a simulator, but thought Matlab would be interesting and give me some data i could work with and compare with in real life.
 
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