Thermal inertia vs effusivity, what is the difference?

[carter7gindenv]

Hello, I'm slowly getting crazy about this stuff. I'm trying to understand what are thermal inertia/effusivity and information have been incoherent so far. The best example of that is seen on wikipedia where the only mention of thermal inertia is in the article
https://en.m.wikipedia.org/wiki/Volumetric_heat_capacity
However in the very section of thermal inertia the article refers to thermal effusivity with the same equation.

I've tried my university physics section but the books talks only about thermal conductivity ( not even thermal diffusivity ).
So far I understood that thermal inertia is akin to mechanical inertia. It is how the material is opposed to change its temperature. I understand that thermal effusivity is how the material exchange heat with its environment. However I don't understand what are their respective equations and why oh god why is it so hard to find information about those concepts.

So here am I humbly asking for helps.
Thanks in advance!

ps: I'm not sure that I posted in the right section : /Edit: two scientific article talking about either effusivity or inertia with the same formula
https://www.hou.usra.edu/meetings/lpsc2015/pdf/2914.pdfhttps://iopscience.iop.org/article/10.1088/0143-0807/24/4/353/meta

 

[Dullard]

Effusivity is a quantitative measure of a material's ability to transfer heat.

Thermal inertia (as I hear it used) addresses the time required for a material to reach thermal equilibrium (longer time = higher thermal inertia) - it tends to be used qualitatively. 'High thermal inertia' could be due to a large quantity of heat being required (specific heat) or poor conductivity, or both.

 

[carter7gindenv]

For what I've read it's thermal diffusivity which describe the time need for an object to reach thermal equilibrium?

 

[Chestermiller]

For what I've read it's thermal diffusivity which describe the time need for an object to reach thermal equilibrium?

This is incorrect.

 

[Chestermiller]

Summary: Difference between thermal inertia and effusivity

Hello, I'm slowly getting crazy about this stuff. I'm trying to understand what are thermal inertia/effusivity and information have been incoherent so far. The best example of that is seen on wikipedia where the only mention of thermal inertia is in the article
https://en.m.wikipedia.org/wiki/Volumetric_heat_capacity
However in the very section of thermal inertia the article refers to thermal effusivity with the same equation.

I've tried my university physics section but the books talks only about thermal conductivity ( not even thermal diffusivity ).
So far I understood that thermal inertia is akin to mechanical inertia. It is how the material is opposed to change its temperature. I understand that thermal effusivity is how the material exchange heat with its environment. However I don't understand what are their respective equations and why oh god why is it so hard to find information about those concepts.

So here am I humbly asking for helps.
Thanks in advance!

ps: I'm not sure that I posted in the right section : /Edit: two scientific article talking about either effusivity or inertia with the same formula
https://www.hou.usra.edu/meetings/lpsc2015/pdf/2914.pdfhttps://iopscience.iop.org/article/10.1088/0143-0807/24/4/353/meta

Your problem is that you are learning this from crappy sources. See Transport Phenomena by Bird, Stewart, and Lightfoot to get a solid fundamental understanding.