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Comsol asking for Ratio of Specific Heats for solid.

Posted 2017年2月1日 GMT-5 08:48 Heat Transfer & Phase Change, Materials, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 5.2 4 Replies

Anthony Lethuillier
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Hello,

I am trying to build a simple model that finds the temperature as a function of time.


The model is part gas / part solid I therefore used the Heat Trasnfer in Fluids physics and I defined the gas and solid parts.

When assigning material properties I use the materials defined in the database but it asks me to fill in the Ratio of Specific Heats for all materials (solid and gases).

According to en.wikipedia.org/wiki/Heat_capacity_ratio this is possible for gases but not for solids.

Am i doing something wrong or is it my understanding of the physics that are wrong ?

Thanks in advance for any help,

I've attached the model I'm working on.

4 Replies Last Post 2017年3月12日 GMT-4 07:29
townbiscuit
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Posted: 7 years ago 2017年2月3日 GMT-5 10:57
Hey Anthony,

I`m still getting used with Comsol, but from my experience, this can happen if you define your physics wrong and you set up a study intended for a gas to a solid.. which could explain why Comsol is asking for the ratio of specific heats. Someone more experienced should confirm this though.
Hey Anthony, I`m still getting used with Comsol, but from my experience, this can happen if you define your physics wrong and you set up a study intended for a gas to a solid.. which could explain why Comsol is asking for the ratio of specific heats. Someone more experienced should confirm this though.
Lay Sotheary
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Posted: 7 years ago 2017年3月11日 GMT-5 02:53
Hi
Did you find this solution? I also met this problem. If you found this solution, please you kindly let me know.

Thank you,
Theary
Hi Did you find this solution? I also met this problem. If you found this solution, please you kindly let me know. Thank you, Theary
Lasse Murtomäki
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Posted: 7 years ago 2017年3月11日 GMT-5 05:37
For solids the ratio is 1.

For gases: Cp - Cv = R

Hence: Cv/Cp = 1 - R/Cp

Ideal gas law applies surprisingly well even at elevated temperatures and pressures.

Lasse
For solids the ratio is 1. For gases: Cp - Cv = R Hence: Cv/Cp = 1 - R/Cp Ideal gas law applies surprisingly well even at elevated temperatures and pressures. Lasse
Lay Sotheary
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Posted: 7 years ago 2017年3月12日 GMT-4 07:29
Thank you, Lasse Murtomäki for your replying.
Thank you, Lasse Murtomäki for your replying.

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