Interfacial thermal resistance

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1

Hello Everyone,

I am interested in calculating interfacial thermal resistance between CNT and polymer where CNT is placed at center of orthogonal simulation box filled with polymer with periodic boundary conditions.

I have created 16 cylindrical bins using chunk/atom where in first Bin I have CNT, adding heat energy into the system, and last 16th cylindrical bin where heat energy is taken out. But as CNT moves It enters into other bins during the simulation.

How can I achieve this? I am thinking to fix the 16th cylindrical bin and make 15th cylindrical bin as heat sink? Is it correct to do so or I am missing?

1 Like
2

A gentler approach would be to make a group of 2 atoms each at each end of the nanotube and apply fix spring/self to those. Since you only want to suppress a (small) drift or rotation, the force constant for the fix could be rather small.
Axel.

3

Thank You, Axel. Will it be okay if I use fix setforce to freeze two or more atoms at each end of nanotube.

4

why not try fix spring/self first? what you suggest is effectively the same as using fix spring/self with an infinitely large force constant.

axel.

5

Thanks, Axel. Based on idea you suggested to apply low force. I thought if I can restrict or freeze some atoms at each end of nanotube. Then CNT movement to other bin can be avoided. I hope there would be no issue.

Thanks,
Ankit

6

hope is not a solid basis for doing science. logical thinking is a much better starting point.

the reasoning is quite simple: if you have to manipulate your system to simplify analysis, you want those manipulations to be as minimal as possible and only as large as necessary to achieve the benefit you are looking for without creating a larger error as necessary. a harmonic restoring force on atoms is much gentler than completely freezing them.

axel.

7

Thank you very much, Axel. I will check it out.