Impact of Mass and Bond Energy Difference and Interface Defects on Thermal Boundary Conductance
Many portions of energy generated in the U.S. are not used and take the form of wasted heat due to a poor heat transfer efficiency. This fact leads research communities to focus on thermoelectrics as a means for using waste heat through direct thermal to electrical energy conversion. One way to enha...
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ndltd-UTAHS-oai-digitalcommons.usu.edu-etd-56722019-10-13T05:31:00Z Impact of Mass and Bond Energy Difference and Interface Defects on Thermal Boundary Conductance Choi, ChangJin Many portions of energy generated in the U.S. are not used and take the form of wasted heat due to a poor heat transfer efficiency. This fact leads research communities to focus on thermoelectrics as a means for using waste heat through direct thermal to electrical energy conversion. One way to enhance thermoelectric efficiency is to reduce thermal conductivity through nanostructuring. In nanostructures, understanding energy transport across the interface of two materials is important because interfaces dominate the resistance to overall thermal transport of the system and can be described by thermal boundary conductance (TBC). Also of note, an understanding of thermal transport cannot be achieved without an understanding of transfer via atomic vibration, known as phonons. In this study, two different techniques of molecular dynamics (MD) simulation are introduced in order to improve the understanding of the phonon transport at the interface of dissimilar materials and the impact of different material properties on TBC. Non-equilibrium MD simulations are used to study relative and combined contributions of mass and bond energy difference on TBC and phonon wave-packet simulations are used to obtain a detailed description of phonon interactions at the interface. At the end of this study, a simple analytical model for the prediction of effective thermal conductivity, using knowledge of thermal boundary resistance, an inverse of TBC, and the interface geometry, is developed. 2016-05-01T07:00:00Z text application/pdf https://digitalcommons.usu.edu/etd/4632 https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=5672&context=etd Copyright for this work is held by the author. Transmission or reproduction of materials protected by copyright beyond that allowed by fair use requires the written permission of the copyright owners. Works not in the public domain cannot be commercially exploited without permission of the copyright owner. Responsibility for any use rests exclusively with the user. For more information contact Andrew Wesolek (andrew.wesolek@usu.edu). All Graduate Theses and Dissertations DigitalCommons@USU Impact of Mass Bond Energy Difference Interface Defects Thermal Boundary Conductance Aerospace Engineering Engineering |
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Impact of Mass Bond Energy Difference Interface Defects Thermal Boundary Conductance Aerospace Engineering Engineering Choi, ChangJin Impact of Mass and Bond Energy Difference and Interface Defects on Thermal Boundary Conductance |
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Many portions of energy generated in the U.S. are not used and take the form of wasted heat due to a poor heat transfer efficiency. This fact leads research communities to focus on thermoelectrics as a means for using waste heat through direct thermal to electrical energy conversion. One way to enhance thermoelectric efficiency is to reduce thermal conductivity through nanostructuring. In nanostructures, understanding energy transport across the interface of two materials is important because interfaces dominate the resistance to overall thermal transport of the system and can be described by thermal boundary conductance (TBC). Also of note, an understanding of thermal transport cannot be achieved without an understanding of transfer via atomic vibration, known as phonons.
In this study, two different techniques of molecular dynamics (MD) simulation are introduced in order to improve the understanding of the phonon transport at the interface of dissimilar materials and the impact of different material properties on TBC. Non-equilibrium MD simulations are used to study relative and combined contributions of mass and bond energy difference on TBC and phonon wave-packet simulations are used to obtain a detailed description of phonon interactions at the interface. At the end of this study, a simple analytical model for the prediction of effective thermal conductivity, using knowledge of thermal boundary resistance, an inverse of TBC, and the interface geometry, is developed. |
author |
Choi, ChangJin |
author_facet |
Choi, ChangJin |
author_sort |
Choi, ChangJin |
title |
Impact of Mass and Bond Energy Difference and Interface Defects on Thermal Boundary Conductance |
title_short |
Impact of Mass and Bond Energy Difference and Interface Defects on Thermal Boundary Conductance |
title_full |
Impact of Mass and Bond Energy Difference and Interface Defects on Thermal Boundary Conductance |
title_fullStr |
Impact of Mass and Bond Energy Difference and Interface Defects on Thermal Boundary Conductance |
title_full_unstemmed |
Impact of Mass and Bond Energy Difference and Interface Defects on Thermal Boundary Conductance |
title_sort |
impact of mass and bond energy difference and interface defects on thermal boundary conductance |
publisher |
DigitalCommons@USU |
publishDate |
2016 |
url |
https://digitalcommons.usu.edu/etd/4632 https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=5672&context=etd |
work_keys_str_mv |
AT choichangjin impactofmassandbondenergydifferenceandinterfacedefectsonthermalboundaryconductance |
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1719265461416230912 |