scholarly journals Preparation of Anisotropic Aerogels with Pristine Graphene by Heat Flow and Study of Their Effects on Heat Transfer in Paraffin

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1622 ◽  
Author(s):  
Jinhui Huang ◽  
Buning Zhang ◽  
Ming He ◽  
Xue Huang ◽  
Guoqiang Yin ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
Flow Direction ◽  
Structural Characteristics ◽  
Low Cost ◽  
Microwave Treatment ◽  
Thermal Conductivity Enhancement ◽  
Graphene Sheets ◽  
Pristine Graphene ◽  
Conductivity Enhancement

In this study, anisotropic graphene/graphene oxide (GO) aerogels (AGAs) were obtained by freeze-drying after direct participation of pristine graphene in the self-assembly of anisotropic gel by the heat flow method. After vacuum microwave treatment, the physical, chemical and structural characteristics of the AGAs were investigated. The results show that AGAs, in which the internal graphene sheets are parallel to the heat flow direction, are successfully prepared. After microwave treatment, the amount of oxygen and nitrogen reduces significantly and the sp2 domain increases. However, at the same time, many fragments and holes are generated in the graphene sheets. The effects of AGAs on the phase transition of paraffin is studied, and the results show that the melting enthalpy, solidification enthalpy and initial melting temperature of AGA/paraffin composites decreases as the GO content in the AGAs increases, whereas the melting range, solidifying range and subcooling degree increases. The highest axial thermal conductivity of the AGA/paraffin composite is 1.45 W/(mK), and the thermal conductivity enhancement efficiency is 884% (AGA content was 0.53 vol %). Compared with previously investigated, similar AGA/paraffin composites, the aerogels fabricated in this study have the obvious advantages of a simple fabrication process, a low cost and a high thermal conductivity enhancement efficiency. These aerogels possess the potential for application in phase-change energy storage (PES), thermal energy management and other fields.

Graphene foam-embedded epoxy composites with significant thermal conductivity enhancement

Nanoscale ◽  
2019 ◽  
Vol 11 (38) ◽  
pp. 17600-17606 ◽  
Author(s):  
Zhiduo Liu ◽  
Yapeng Chen ◽  
Yifan Li ◽  
Wen Dai ◽  
Qingwei Yan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Polymer Composites ◽  
Thermal Transport ◽  
Low Cost ◽  
Three Dimensional ◽  
Thermal Conductivity Enhancement ◽  
Epoxy Composites ◽  
Graphene Foam ◽  
Conductivity Enhancement ◽  
Transport Channels

A facile, low-cost and scalable method is developed to construct three-dimensional thermal transport channels like highways in polymer composites.

THERMAL CONDUCTIVITY ENHANCEMENT OF MATERIAL FOR CALCIUM CHLORIDE/WATER THERMOCHEMICAL ENERGY STORAGE

2018 ◽  
Author(s):  
Takuma Ohtaki ◽  
Maho Mitsuo ◽  
Takayuki Terauchi ◽  
Hiroshi Iguchi ◽  
Keiko Fujioka ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Energy Storage ◽  
Calcium Chloride ◽  
Thermal Conductivity Enhancement ◽  
Conductivity Enhancement ◽  
Chloride Water

scholarly journals Anomalous thermal conductivity enhancement in low dimensional resonant nanostructures due to imperfections

Nanoscale ◽  
2021 ◽  
Author(s):  
Hongying Wang ◽  
Yajuan Cheng ◽  
Zheyong Fan ◽  
Yangyu Guo ◽  
Zhongwei Zhang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Energy Conversion ◽  
Thermal Conductivity Enhancement ◽  
Heat Management ◽  
Thermoelectric Energy Conversion ◽  
Conductivity Enhancement ◽  
Thermoelectric Energy ◽  
Low Dimensional

Nanophononic metamaterials have broad applications in fields such as heat management, thermoelectric energy conversion, and nanoelectronics. Phonon resonance in pillared low-dimensional structures has been suggested to be a feasible approach...

scholarly journals Thermal Conductivity of Ionic Liquids and IoNanofluids. Can Molecular Theory Help?

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 116
Author(s):  
Xavier Paredes ◽  
Maria José Lourenço ◽  
Carlos Nieto de Castro ◽  
William Wakeham
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Ionic Liquids ◽  
Imaging Techniques ◽  
Interfacial Area ◽  
Thermal Conductivity Enhancement ◽  
Molecular Theory ◽  
Estimation Methods ◽  
Diphenyl Oxide ◽  
Conductivity Enhancement

Ionic liquids have been suggested as new engineering fluids, specifically in the area of heat transfer, and as alternatives to current biphenyl and diphenyl oxide, alkylated aromatics and dimethyl polysiloxane oils, which degrade above 200 °C, posing some environmental problems. Addition of nanoparticles to produce stable dispersions/gels of ionic liquids has proved to increase the thermal conductivity of the base ionic liquid, potentially contributing to better efficiency of heat transfer fluids. It is the purpose of this paper to analyze the prediction and estimation of the thermal conductivity of ionic liquids and IoNanofluids as a function of temperature, using the molecular theory of Bridgman and estimation methods previously developed for the base fluid. In addition, we consider methods that emphasize the importance of the interfacial area IL-NM in modelling the thermal conductivity enhancement. Results obtained show that it is not currently possible to predict or estimate the thermal conductivity of ionic liquids with an uncertainty commensurate with the best experimental values. The models of Maxwell and Hamilton are not capable of estimating the thermal conductivity enhancement of IoNanofluids, and it is clear that the Murshed, Leong and Yang model is not practical, if no additional information, either using imaging techniques at nanoscale or molecular dynamics simulations, is available.

Sign in / Sign up

Export Citation Format

Share Document