When a Carbon/PAEK material heated with an alternative current, I have seen a rapid/moderate/linear temperature drop after cutting the heat supply from the heat source. Even it continues for the further cycles for the same sample at a constant relative time. I have observed the same patterns profile of cooling and heating cycles.
Is it because of morphology of a material or heat capacity of the material ?
Could you please explain the behaviour here and if possible suggest me some articles to read?
Note: The sample has air cooled after cutting the heat supply.
Any suggestion would be appreciated.
Hello Nagamani,
For a more accurate explanation it would be better to describe your test setup.
Nevertheless, materials have heat capacity, i.e. they have the ability to store heat. For this reason, the temperature of a material cannot change instanlty but it requires some time. The amount of time depends on the power of the heat source, the ambient temperature and the test setup (i.e. thermal resistance of the materials).
Thank you very much Mr. Michalis Florides for answering.
Coming to test setup the material is kept between to copper plates on two probe method. The heat supply was attached to the copper plates from both ends plates.
After heating as a result for different samples I can observe the same pattern in 5 cycles but not same temperature drop for every material.
For every sample, the power of heat source and time is similar.
I would like to know that behaviour.
A reason could be if the samples are of different size, then they have a different heat capacity. This means that the time for the temperature change of each material is different.
Another reason could be that the thermal resistance of the interface between the samples and the plates is not exactly the same every time you test a different sample. If not, you could use thermal paste or thermal conducitve pads between the sample and the copper plates to improve repeatability.
Do you have any graphs and the test sequence of the samples? What is the time between each sample test? Is the ambient temperature always the same? A photo of the setup could be helpful.
- Badges
- Science topic