Analytical model for phonon transport analysis of periodic bulk nanoporous structures
Affiliation
Department of Aerospace and Mechanical Engineering, University of ArizonaIssue Date
2017-01-25
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PERGAMON-ELSEVIER SCIENCE LTDCitation
Analytical model for phonon transport analysis of periodic bulk nanoporous structures 2017, 111:1409 Applied Thermal EngineeringJournal
Applied Thermal EngineeringRights
© 2016 Elsevier Ltd. All rights reserved.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Phonon transport analysis in nano- and micro-porous materials is critical to their energy-related applications. Assuming diffusive phonon scattering by pore edges, the lattice thermal conductivity can be predicted by modifying the bulk phonon mean free paths with the characteristic length of the nanoporous structure, i.e., the phonon mean free path (Lambda(pore)) for the pore-edge scattering of phonons. In previous studies (Jean et al., 2014), a Monte Carlo (MC) technique have been employed to extract geometry determined Lambda(pore) for nanoporous bulk materials with selected periods and porosities. In other studies (Minnich and Chen, 2007; Machrafi and Lebon, 2015), simple expressions have been proposed to compute Lambda(pore). However, some divergence can often be found between lattice thermal conductivities predicted by phonon MC simulations and by analytical models using Lambda(pore). In this work, the effective Lambda(pore) values are extracted by matching the frequency-dependent phonon MC simulations with the analytical model for nanoporous bulk Si. The obtained Lambda(pore) values are usually smaller than their analytical expressions. These new values are further confirmed by frequency-dependent phonon MC simulations on nano porous bulk Ge. By normalizing the volumetric surface area A and Lambda(pore) with the period length p, the same curve can be used for bulk materials with aligned cubic or spherical pores up to dimensionless p.A of 1.5. Available experimental data for nanoporous Si materials are further analyzed with new Lambda(pore) values. In practice, the proposed model can be employed for the thermal analysis of various nanoporous materials and thus replace the time-consuming phonon MC simulations.Note
24 month embargo; Available online 14 June 2016ISSN
13594311Version
Final accepted manuscriptAdditional Links
http://linkinghub.elsevier.com/retrieve/pii/S1359431116309899ae974a485f413a2113503eed53cd6c53
10.1016/j.applthermaleng.2016.06.075