scholarly journals Effect of Particle Sizes of Nickel Powder on Thermal Conductivity of Epoxy Resin-Based Composites under Magnetic Alignment

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1990
Author(s):  
Zheng Jin ◽  
Fei Liang ◽  
Wenzhong Lu ◽  
Jinhang Dai ◽  
Shunliang Meng ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Particle Size ◽  
Aluminum Nitride ◽  
Epoxy Resin ◽  
Nickel Powder ◽  
Chain Structure ◽  
Particle Sizes ◽  
Anisotropic Thermal Conductivity ◽  
Powder Particles

Magnetically oriented three-phase composite systems of epoxy resin, aluminum nitride, and nickel have been prepared, the thermal conductivity of composites filled with nickel powder with different particle sizes and content under different applied magnetic fields was studied. The vibrating scanning magnetometer (VSM) and scanning electron microscopy (SEM) were applied to investigate the dispersion of nickel powder in the composites. The results showed that the anisotropic thermal conductivity of the composites treated by applied magnetic field forming chain structure is obtained. The epoxy resin-based composites filled with 30 vol% aluminum nitride with particle size of 1 μm and 2 vol% nickel powder with particle size of 1 μm and aligned with vertical magnetic field have the highest thermal conductivity (1.474 W/mk), which increases the thermal conductivity of the composites by 737% and 58% compared to the pure epoxy resin (0.2 W/mk) and the composites filled with 30 vol% aluminum nitride (0.933 W/mk). In addition, we simulated the influence of nickel powder particles with different particle sizes and arrangements on the thermal conductivity of the composite material in COMSOL Multiphysics software, and the results were consistent with the experimental results.

scholarly journals Preparation and Thermal Conductivity of Epoxy Resin/Graphene-Fe3O4 Composites

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2013
Author(s):  
Zhong Wu ◽  
Jingyun Chen ◽  
Qifeng Li ◽  
Da-Hai Xia ◽  
Yida Deng ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Thermal Stability ◽  
Epoxy Resin ◽  
Thermomechanical Properties ◽  
Packaging Materials ◽  
Mass Ratio ◽  
Degree Of Orientation ◽  
Ep Matrix ◽  
Electrical Insulation Properties

By modifying the bonding of graphene (GR) and Fe3O4, a stable structure of GR-Fe3O4, namely magnetic GR, was obtained. Under the induction of a magnetic field, it can be orientated in an epoxy resin (EP) matrix, thus preparing EP/GR-Fe3O4 composites. The effects of the content of GR and the degree of orientation on the thermal conductivity of the composites were investigated, and the most suitable Fe3O4 load on GR was obtained. When the mass ratio of GR and Fe3O4 was 2:1, the thermal conductivity could be increased by 54.8% compared with that of pure EP. Meanwhile, EP/GR-Fe3O4 composites had a better thermal stability, dynamic thermomechanical properties, and excellent electrical insulation properties, which can meet the requirements of electronic packaging materials.

Binary Particle Mixtures as a Heat Transfer Media in Shell-and-Plate Moving Packed Bed Heat Exchangers

2021 ◽  
Author(s):  
Chase Ellsworth Christen
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Particle Size ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Packed Bed ◽  
Particle Sizes ◽  
Overall Heat Transfer Coefficient ◽  
Solid Media

Solid particles are being considered in several high temperature thermal energy storage systems and as heat transfer media in concentrated solar power (CSP) plants. The downside of such an approach is the low overall heat transfer coefficients in shell-and-plate moving packed bed heat exchangers caused by the inherently low packed bed thermal conductivity values of the low-cost solid media. Choosing the right particle size distribution of currently available solid media can make a substantial difference in packed bed thermal conductivity, and thus, a substantial difference in the overall heat transfer coefficient of shell-and-plate moving packed bed heat exchangers. Current research exclusively focuses on continuous unimodal distributions of alumina particles. The drawback of this approach is that larger particle sizes require wider particle channels to meet flowability requirements. As a result, only small particle sizes with low packed bed thermal conductivities have been considered for the use in the falling-particle Gen3 CSP concepts. Here, binary particle mixtures, which are defined in this thesis as a mixture of two continuous unimodal particle distributions leading to a continuous bimodal particle distribution, are considered to increase packed bed thermal conductivity, decrease packed bed porosity, and improve moving packed bed heat exchanger performance. This is the first study related to CSP solid particle heat transfer that has considered the packed bed thermal conductivity and moving packed bed heat exchanger performance of bimodal particle size distributions at room and elevated temperatures. Considering binary particle mixtures that meet particle sifting segregation criteria, the overall heat transfer coefficient of shell-and-plate moving packed bed heat exchangers can be increased by 23% when compared to a monodisperse particle system. This work demonstrates that binary particle mixtures should be seriously considered to improve shell-and-plate moving packed bed heat exchangers.

Liquid Layering and the Enhanced Thermal Conductivity of Ar-Cu Nanofluids: A Molecular Dynamics Study

2016 ◽  
Author(s):  
Jithu Paul ◽  
A. K. Madhu ◽  
U. B. Jayadeep ◽  
C. B. Sobhan
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Particle Size ◽  
Molecular Dynamics Simulations ◽  
Volume Fraction ◽  
Strong Dependence ◽  
Particle Sizes ◽  
Dynamics Simulations ◽  
Enhanced Thermal Conductivity ◽  
Liquid Layering

Nanofluids — colloidal suspensions of nanoparticles in base fluids — are known to possess superior thermal properties compared to the base fluids. Various theoretical models have been suggested to explain the often anomalous enhancement of these properties. Liquid layering around the nanoparticle is one of such reasons. The effect of the particle size on the extent of liquid layering around the nanoparticle has been investigated in the present study. Classical molecular dynamics simulations have been performed in the investigation, considering the case of a copper nanoparticle suspended in liquid argon. The results show a strong dependence of thickness of the liquid layer on the particle size, below a particle diameter of 4nm. To establish the role of liquid layering in the enhancement of thermal conductivity, simulations have been performed at constant volume fraction for different particle sizes using Green Kubo formalism. The thermal conductivity results show 100% enhancement at 3.34% volume fraction for particle size of 2nm. The results establish the dominant role played by liquid layering in the enhanced thermal conductivity of nanofluids at the low particle sizes used. Contrary to the previous findings, the molecular dynamics simulations also predict a strong dependence of the liquid layer thickness on the particle size in the case of small particles.

The Thermal and Di-Electric Properties of a Silicone-Based Thermal Pad

2011 ◽  
Vol 295-297 ◽  
pp. 804-807 ◽  
Author(s):  
Wern Shiarng Jou ◽  
Chih Feng Hsu ◽  
Yu Kun Yeh
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Dielectric Properties ◽  
Electrical Property ◽  
Single Particle ◽  
Electric Properties ◽  
Particle Sizes ◽  
Mixing Ratio

The properties of a silicone-based elastomeric thermal pad filled with inexpensive ceramic additives were studied in this research. The effects of the content, particle size and mixing ratio of two additives upon the thermal and di-electrical property of the thermal pad are investigated. The result shows that the higher the content, the higher the thermal and dielectric properties are. In addition, the thermal conductivity of two particles filled thermal pads are higher than that of a single particle filled thermal pad. The thermal conductivity of the two kind of particle sizes (14 and 2 um) of 60 % (vol.) SiC filled thermal pad is the highest (2.14 W/m·K).

scholarly journals Measuring anisotropic thermal conductivity of aluminum nitride films with the ultra-fast hot strip technique

2020 ◽  
Vol 151 ◽  
pp. 106259
Author(s):  
B.E. Belkerk ◽  
J. Camus ◽  
B. Garnier ◽  
H. Al Brithen ◽  
S. Sahli ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Aluminum Nitride ◽  
Anisotropic Thermal Conductivity ◽  
Hot Strip

Thermal Conductivity Affected by Temperature and Particle Size in Al2O3-Water Nanofluids

2011 ◽  
Author(s):  
D. Kwek ◽  
A. Crivoi ◽  
Fei Duan
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Effective Thermal Conductivity ◽  
Experimental Results ◽  
Al2o3 Nanoparticles ◽  
Particle Sizes ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
Nanoparticle Concentration ◽  
Wire Method

The effective thermal conductivity of Al2O3-water nanofluids has been measured using a transient hot wire method. Experimental results demonstrate that the thermal conductivity of Al2O3 nanofluids increases linearly with increasing nanoparticle concentration. Adding 5 vol % of Al2O3 nanoparticles in water increases the effective thermal conductivity of the nanofluids by 20%. Thermal conductivity of Al2O3 nanofluids increases with an increase of temperature. The enhancement is around 1.7% at 15 °C in comparison with around 16% at 55 °C in a 1 vol % nanofluid. The particle size is another important parameter for the effective thermal conductivity. The increase of thermal conductivity reduces from 30% to 10% as the particle sizes increase from 10 nm to 35 nm. The increase of the effective thermal conductivity starts as the particle size increases above 35 nm, reaching about 27.5% in the nanofluid with the particle size at 150 nm.

scholarly journals Magnetic Field Effect on Thermal, Dielectric, and Viscous Properties of a Transformer Oil-Based Magnetic Nanofluid

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4532 ◽  
Author(s):  
Michal Rajnak ◽  
Zan Wu ◽  
Bystrik Dolnik ◽  
Katarina Paulovicova ◽  
Jana Tothova ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Volume Fraction ◽  
Effective Medium Theory ◽  
Transformer Oil ◽  
Dielectric Anisotropy ◽  
Magnetic Nanofluid ◽  
Conductivity Sensor ◽  
Anisotropic Thermal Conductivity ◽  
Transformer Oils

Progress in electrical engineering puts a greater demand on the cooling and insulating properties of liquid media, such as transformer oils. To enhance their performance, researchers develop various nanofluids based on transformer oils. In this study, we focus on novel commercial transformer oil and a magnetic nanofluid containing iron oxide nanoparticles. Three key properties are experimentally investigated in this paper. Thermal conductivity was studied by a transient plane source method dependent on the magnetic volume fraction and external magnetic field. It is shown that the classical effective medium theory, such as the Maxwell model, fails to explain the obtained results. We highlight the importance of the magnetic field distribution and the location of the thermal conductivity sensor in the analysis of the anisotropic thermal conductivity. Dielectric permittivity of the magnetic nanofluid, dependent on electric field frequency and magnetic volume fraction, was measured by an LCR meter. The measurements were carried out in thin sample cells yielding unusual magneto-dielectric anisotropy, which was dependent on the magnetic volume fraction. Finally, the viscosity of the studied magnetic fluid was experimentally studied by means of a rheometer with a magneto-rheological device. The measurements proved the magneto-viscous effect, which intensifies with increasing magnetic volume fraction.

scholarly journals A Study on the utilization of coffee grounds for particle board

2021 ◽  
Vol 10 (2) ◽  
pp. 48-52
Author(s):  
Cut Rizka Maulida ◽  
Mursal Mursal ◽  
Ismail Ismail
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Compressive Strength ◽  
Physical Properties ◽  
Epoxy Resin ◽  
Particle Sizes ◽  
Particle Board ◽  
Thickness Swelling ◽  
Coffee Grounds ◽  
Coffee Ground

Abstrak. Penelitian ini bertujuan untuk membuat papan partikel dengan menggunakan limbah ampas kopi dan resin epoksi sebagai perekat. Komposisi resin epoksi divariasikan yaitu 5, 10, 15 dan 20 vol.% untuk masing-masing partikel ampas kopi berukuran 20 dan 40 mesh. Papan partikel dibuat dengan teknik pressing dengan beban sebesar 9 ton selama 30 menit. Sifat mekanik yang diuji adalah MOE, MOR, dan kuat tekan. Sifat fisis papan partikel yang diuji adalah kerapatan dan pengembangan tebal. Hasil menunjukkan bahwa nilai MOE tertinggi yaitu 20,910 kgf/cm2 pada komposisi 95 vol.% ampas kopi dan 5 vol.% resin epoksi dengan ukuran ampas kopi 40 mesh. MOR tertinggi yaitu 167 kgf/cm2 pada ukuran partikel 40 mesh dengan komposisi ampas kopi 90 vol.% dan resin epoksi 10 vol.%. Nilai kuat tekan tertinggi diperoleh 220 kgf/cm2 pada 20 mesh, dengan komposisi 85 vol.% ampas kopi dan 15 vol.% resin epoksi. Kerapatan dan pengembangan tebal papan partikel yang tertinggi masing-masing adalah 1,16 g/cm3 dan 0,85%. Secara umum, sifat mekanis papan partikel ampas kopi tergantung pada komposisi dan ukuran partikel ampas kopi. Namun, sifat fisisnya tidak berubah secara signifikan untuk ukuran partikel dan komposisi yang berbeda. Papan partikel yang diperoleh dari penelitian ini memenuhi standar ANSI sehingga berpotensi untuk dijadikan sebagai papan partikel atau komposit. Abstract.. This study aims to make a particle board using coffee ground waste and epoxy resin as an adhesive. The composition of the epoxy resin was varied, namely 5, 10, 15 and 20 vol.% for 20 mesh and 40 mesh of coffee grounds particles. Particle board is made by pressing technique with a load of 9 tons for 30 minutes. The mechanical properties tested were MOE, MOR, and compressive strength. The physical properties of the particle board tested were density and thickness swelling. The results showed that the highest MOE particle board was 20.910 kgf/cm2 (95 vol.% coffee grounds:5 vol.% epoxy resin; 40 mesh). The highest MOR was 167 kgf/cm2 (90 vol.% coffee grounds:10 vol.% epoxy resin;40 mesh). The hihgest compressive strength values was 220 kgf/cm2 (85 vol.% coffee grounds:15 vol.% epoxy resin;20 mesh). The highest density and thickness expansion were 1.16 g/cm3 and 0.85%, respectively. In general, the mechanical properties of coffee grounds particleboard depend on the composition and particle size of coffee grounds. However, their physical properties do not change significantly for different particle sizes and compositions. The particle board obtained from this study meets the standard of ANSI. Thus, coffee grounds have the potential to be used as particle board or composite. Keywords particle board, coffee grounds, epoxy resin, mechanical properties, physical properties

Studies on the Thermal Conductivity of Al2O3/Epoxy Resin Composite Materials

2012 ◽  
Vol 535-537 ◽  
pp. 235-238 ◽  
Author(s):  
Xiao Hu Wan ◽  
Li Ge Wang ◽  
Bin Zuo ◽  
En Ze Wang ◽  
Guang Zhi Zhu
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Composite Materials ◽  
Epoxy Resin ◽  
Resin Composite ◽  
Pure Epoxy ◽  
Mean Particle Size ◽  
Epoxy Resin Composite

Al2O3/epoxy resin composite materials were prepared with alumina as filler in this paper, and the effects of particle size and added quantity of Al2O3 powers on the thermal conductivity of the composites have been investigated. The results show that, thermal conductivity of the composites increases with the increase of the added quantity of Al2O3 powders, and suitable particle size of alumina filler could help to form heat conductive chain which can improve the thermal conductivity of the composites effectively. The thermal conductivity could reach 0.48 W/(m•K), which is five times than that of pure epoxy resin, when the amount of alumina powders is 60% and its mean particle size is 100µm.

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