Asymmetrical carbon nanotubes exhibit opposing thermal rectification behaviors under different heat baths

Wei-Jen Chen, Biao Feng, Cheng Shao, Jin Yang, Liwu Fan, Wee-Liat Ong, I-Ling Chang

Research output: Contribution to journalArticlepeer-review

Abstract

Asymmetrical nanostructures are leading candidates to create efficient thermal rectifiers critical in thermal management and energy conversion systems. Due to their nanoscale size and inherent non-equilibrium nature, their working principles are commonly elucidated through non-equilibrium molecular dynamic simulations. Using asymmetrical carbon nanotubes, the resulting thermal rectification under different heat baths is found to differ in magnitude and direction. We find that nanotubes with the Langevin baths have a higher thermal conductivity in one heat flow direction due to the low-frequency phonons, resulting in a positive rectification. On the other hand, nanotubes with the Nose-Hoover baths show similar thermal conductivity contributions in both heat flow directions across the whole phonon frequency range, culminating in a negative rectification. Our work highlights how asymmetrical carbon nanostructures can rectify heat flow differently under different heat baths and provides strong evidence for the need to consider their non-equilibrium phonon spectrum before analyzing any associated nanoscale thermal transport phenomena.
Original languageEnglish (US)
Pages (from-to)122341
JournalInternational Journal of Heat and Mass Transfer
Volume184
DOIs
StatePublished - Dec 11 2021
Externally publishedYes

ASJC Scopus subject areas

  • Mechanical Engineering
  • Fluid Flow and Transfer Processes
  • Condensed Matter Physics

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