Nanomaterials

Editorial

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2 pages, 176 KiB

Open AccessEditorial

Heat Transfer in Nanostructured Materials

by Ming-Hui Lu

Nanomaterials 2023, 13(6), 1062; https://doi.org/10.3390/nano13061062 - 15 Mar 2023

Viewed by 1530

Abstract

Thermal manipulation has garnered considerable attention for its potential applications in diverse areas, including microelectronics, thermal logic devices, and thermoelectrics [...] Full article

(This article belongs to the Special Issue Heat Transfer in Nanostructured Materials)

Research

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9 pages, 2131 KiB

Open AccessCommunication

A Hierarchically Structured Graphene/Ag Nanowires Paper as Thermal Interface Material

by Le Lv, Junfeng Ying, Lu Chen, Peidi Tao, Liwen Sun, Ke Yang, Li Fu, Jinhong Yu, Qingwei Yan, Wen Dai, Nan Jiang and Cheng-Te Lin

Nanomaterials 2023, 13(5), 793; https://doi.org/10.3390/nano13050793 - 21 Feb 2023

Cited by 6 | Viewed by 2083

Abstract

With the increase in heat power density in modern integrating electronics, thermal interface materials (TIM) that can efficiently fill the gaps between the heat source and heat sinks and enhance heat dissipation are urgently needed owing to their high thermal conductivity and excellent [...] Read more.

With the increase in heat power density in modern integrating electronics, thermal interface materials (TIM) that can efficiently fill the gaps between the heat source and heat sinks and enhance heat dissipation are urgently needed owing to their high thermal conductivity and excellent mechanical durability. Among all the emerged TIMs, graphene-based TIMs have attracted increasing attention because of the ultrahigh intrinsic thermal conductivity of graphene nanosheets. Despite extensive efforts, developing high-performance graphene-based papers with high through-plane thermal conductivity remains challenging despite their high in-plane thermal conductivity. In this study, a novel strategy for enhancing the through-plane thermal conductivity of graphene papers by in situ depositing AgNWs on graphene sheets (IGAP) was proposed, which could boost the through-plane thermal conductivity of the graphene paper up to 7.48 W m⁻¹ K⁻¹ under packaging conditions. In the TIM performance test under actual and simulated operating conditions, our IGAP exhibits strongly enhanced heat dissipation performance compared to the commercial thermal pads. We envision that our IGAP as a TIM has great potential for boosting the development of next-generation integrating circuit electronics. Full article

(This article belongs to the Special Issue Heat Transfer in Nanostructured Materials)

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13 pages, 1904 KiB

Open AccessArticle

How Hydrodynamic Phonon Transport Determines the Convergence of Thermal Conductivity in Two-Dimensional Materials

by Jianhui Jiang, Shuang Lu, Yulou Ouyang and Jie Chen

Nanomaterials 2022, 12(16), 2854; https://doi.org/10.3390/nano12162854 - 18 Aug 2022

Cited by 10 | Viewed by 2176

Abstract

The phonon Boltzmann transport equation combined with first-principles calculation has achieved great success in exploring the lattice thermal conductivity (

κ

) of various materials. However, the convergence of the predicted

κ

is a critical issue, leading to quite scattered results recorded in [...] Read more.

The phonon Boltzmann transport equation combined with first-principles calculation has achieved great success in exploring the lattice thermal conductivity (

κ

) of various materials. However, the convergence of the predicted

κ

is a critical issue, leading to quite scattered results recorded in the literature, even for the same material. In this paper, we explore the origin for the convergence of thermal conductivity in two-dimensional (2D) materials. Two kinds of typical 2D materials, graphene and silicene, are studied, and the bulk silicon is also compared as a control system for a three-dimensional material. The effect of the cutoff radius (

r_{c}

) in the third-order interatomic force constants on

κ

is studied for these three materials. It is found that that

κ

of these three materials exhibits diverse convergence behaviors with respect to

r_{c}

, which coincides very well with the strength of hydrodynamic phonon transport. By further analyzing the phonon lifetime and scattering rates, we reveal that the dominance of the normal scattering process gives rise to the hydrodynamic phonon transport in both graphene and silicene, which results in long-range interaction and a large lifetime of low-frequency flexural acoustic phonons, while the same phenomenon is absent in bulk silicon. Our study highlights the importance of long-range interaction associated with hydrodynamic phonon transport in determining the thermal conductivity of 2D materials. Full article

(This article belongs to the Special Issue Heat Transfer in Nanostructured Materials)

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22 pages, 3815 KiB

Open AccessArticle

Exploring the Impact of the Linker Length on Heat Transport in Metal–Organic Frameworks

by Sandro Wieser, Tomas Kamencek, Rochus Schmid, Natalia Bedoya-Martínez and Egbert Zojer

Nanomaterials 2022, 12(13), 2142; https://doi.org/10.3390/nano12132142 - 22 Jun 2022

Cited by 6 | Viewed by 2410

Abstract

Metal–organic frameworks (MOFs) are a highly versatile group of porous materials suitable for a broad range of applications, which often crucially depend on the MOFs’ heat transport properties. Nevertheless, detailed relationships between the chemical structure of MOFs and their thermal conductivities are still [...] Read more.

Metal–organic frameworks (MOFs) are a highly versatile group of porous materials suitable for a broad range of applications, which often crucially depend on the MOFs’ heat transport properties. Nevertheless, detailed relationships between the chemical structure of MOFs and their thermal conductivities are still largely missing. To lay the foundations for developing such relationships, we performed non-equilibrium molecular dynamics simulations to analyze heat transport in a selected set of materials. In particular, we focus on the impact of organic linkers, the inorganic nodes and the interfaces between them. To obtain reliable data, great care was taken to generate and thoroughly benchmark system-specific force fields building on ab-initio-based reference data. To systematically separate the different factors arising from the complex structures of MOF, we also studied a series of suitably designed model systems. Notably, besides the expected trend that longer linkers lead to a reduction in thermal conductivity due to an increase in porosity, they also cause an increase in the interface resistance between the different building blocks of the MOFs. This is relevant insofar as the interface resistance dominates the total thermal resistance of the MOF. Employing suitably designed model systems, it can be shown that this dominance of the interface resistance is not the consequence of the specific, potentially weak, chemical interactions between nodes and linkers. Rather, it is inherent to the framework structures of the MOFs. These findings improve our understanding of heat transport in MOFs and will help in tailoring the thermal conductivities of MOFs for specific applications. Full article

(This article belongs to the Special Issue Heat Transfer in Nanostructured Materials)

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16 pages, 4903 KiB

Open AccessArticle

Heat Transfer Analysis of Nanostructured Material Flow over an Exponentially Stretching Surface: A Comparative Study

by Mubashar Arshad, Azad Hussain, Ali Hassan, Ilyas Khan, Mohamed Badran, Sadok Mehrez, Ashraf Elfasakhany, Thabet Abdeljawad and Ahmed M. Galal

Nanomaterials 2022, 12(7), 1204; https://doi.org/10.3390/nano12071204 - 4 Apr 2022

Cited by 22 | Viewed by 2172

Abstract

The objective of the present research is to obtain enhanced heat and reduce skin friction rates. Different nanofluids are employed over an exponentially stretching surface to analyze the heat transfer coefficients. The mathematical model for the problem has been derived with the help [...] Read more.

The objective of the present research is to obtain enhanced heat and reduce skin friction rates. Different nanofluids are employed over an exponentially stretching surface to analyze the heat transfer coefficients. The mathematical model for the problem has been derived with the help of the Rivilin–Erickson tensor and an appropriate boundary layer approximation theory. The current problem has been tackled with the help of the boundary value problem algorithm in Matlab. The convergence criterion, or tolerance for this particular problem, is set at 10⁻⁶. The outcomes are obtained to demonstrate the characteristics of different parameters, such as the temperature exponent, volume fraction, and stretching ratio parameter graphically. Silver-water nanofluid proved to have a high-temperature transfer rate when compared with zinc-water and copper-water nanofluid. Moreover, the outcomes of the study are validated by providing a comparison with already published work. The results of this study were found to be in complete agreement with those of Magyari and Keller and also with Lui for heat transfer. The novelty of this work is the comparative inspection of enhanced heat transfer rates and reduced drag and lift coefficients, particularly for three nanofluids, namely, zinc-water, copper-water, and silver-water, over an exponentially stretching. In general, this study suggests more frequent exploitation of all the examined nanofluids, especially

Ag

-water nanofluid. Moreover, specifically under the obtained outcomes in this research, the examined nanofluid, Ag-water, has great potential to be used in flat plate solar collectors. Ag-water can also be tested in natural convective flat plate solar collector systems under real solar effects. Full article

(This article belongs to the Special Issue Heat Transfer in Nanostructured Materials)

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55 pages, 12539 KiB

Open AccessArticle

Nanofluid Heat Transfer: Enhancement of the Heat Transfer Coefficient inside Microchannels

by Kevin Apmann, Ryan Fulmer, Branden Scherer, Sawyer Good, Jake Wohld and Saeid Vafaei

Nanomaterials 2022, 12(4), 615; https://doi.org/10.3390/nano12040615 - 11 Feb 2022

Cited by 34 | Viewed by 3694

Abstract

The purpose of this paper is to investigate the effects of a connector between two microchannels, for the first time. A brief literature review is provided to offer a better understanding on the impacts of concentration and the characteristics of nanoparticles on thermal [...] Read more.

The purpose of this paper is to investigate the effects of a connector between two microchannels, for the first time. A brief literature review is provided to offer a better understanding on the impacts of concentration and the characteristics of nanoparticles on thermal conductivity, viscosity, and, consequently, the heat transfer coefficient inside the microchannels. The given literature review aims to help engineer nanofluids to enhance the heat transfer coefficient inside the microchannels. In this research, Fe₃O₄ nanoparticles were introduced into the base liquid to enhance the heat transfer coefficient inside the microchannels and to provide a better understanding of the impact of the connector between two microchannels. It was observed that the connector has a significant impact on enhancing the heat transfer coefficient inside the second microchannel, by increasing the level of randomness of molecules and particles prior to entering the second channel. The connector would act to refresh the memory of the fluid before entering the second channel, and as a result, the heat transfer coefficient in the second channel would start at a maximum value. Therefore, the overall heat transfer coefficient in both microchannels would increase for given conditions. The impacts of the Reynolds number and introducing nanoparticles in the base liquid on effects induced by the connector were investigated, suggesting that both factors play a significant role on the connector’s impact on the heat transfer coefficient. Full article

(This article belongs to the Special Issue Heat Transfer in Nanostructured Materials)

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9 pages, 1550 KiB

Open AccessArticle

Thermal Conductivity of VO₂ Nanowires at Metal-Insulator Transition Temperature

by Da Li, Qilang Wang and Xiangfan Xu

Nanomaterials 2021, 11(9), 2428; https://doi.org/10.3390/nano11092428 - 17 Sep 2021

Cited by 7 | Viewed by 3135

Abstract

Vanadium dioxide (VO₂) nanowires endowed with a dramatic metal−insulator transition have attracted enormous attention. Here, the thermal conductance of VO₂ nanowires with different sizes, measured using the thermal bridge method, is reported. A size-dependent thermal conductivity was observed where the [...] Read more.

Vanadium dioxide (VO₂) nanowires endowed with a dramatic metal−insulator transition have attracted enormous attention. Here, the thermal conductance of VO₂ nanowires with different sizes, measured using the thermal bridge method, is reported. A size-dependent thermal conductivity was observed where the thicker nanowire showed a higher thermal conductivity. Meanwhile, the thermal conductivity jump at metal−insulator transition temperature was measured to be much higher in the thicker samples. The dominant heat carriers were phonons both at the metallic and the insulating regimes in the measured samples, which may result from the coexistence of metal and insulator phases at high temperature. Our results provide a window into exploring the mechanism of the metal−insulator transition of VO₂ nanowires. Full article

(This article belongs to the Special Issue Heat Transfer in Nanostructured Materials)

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Review

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22 pages, 3936 KiB

Open AccessReview

Recent Advances in Thermal Interface Materials for Thermal Management of High-Power Electronics

by Wenkui Xing, Yue Xu, Chengyi Song and Tao Deng

Nanomaterials 2022, 12(19), 3365; https://doi.org/10.3390/nano12193365 - 27 Sep 2022

Cited by 47 | Viewed by 12502

Abstract

With the increased level of integration and miniaturization of modern electronics, high-power density electronics require efficient heat dissipation per unit area. To improve the heat dissipation capability of high-power electronic systems, advanced thermal interface materials (TIMs) with high thermal conductivity and low interfacial [...] Read more.

With the increased level of integration and miniaturization of modern electronics, high-power density electronics require efficient heat dissipation per unit area. To improve the heat dissipation capability of high-power electronic systems, advanced thermal interface materials (TIMs) with high thermal conductivity and low interfacial thermal resistance are urgently needed in the structural design of advanced electronics. Metal-, carbon- and polymer-based TIMs can reach high thermal conductivity and are promising for heat dissipation in high-power electronics. This review article introduces the heat dissipation models, classification, performances and fabrication methods of advanced TIMs, and provides a summary of the recent research status and developing trends of micro- and nanoscale TIMs used for heat dissipation in high-power electronics. Full article

(This article belongs to the Special Issue Heat Transfer in Nanostructured Materials)

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