Numerical Study of Nanocomposites for Energy Applications

2020 ◽  
pp. 1-31
Author(s):  
Siddhartha Kosti
Keyword(s):  
Thermal Conductivity ◽  
Numerical Study ◽  
Numerical Models ◽  
Base Material ◽  
Volume Ratio ◽  
High Heat ◽  
Effective Density ◽  
Energy Transfer Rate ◽  
Energy Devices ◽  
Energy Applications

Nanocomposites are defined as a combination of nanoparticles reinforced into the base material. They are of very small sizes (1nm = 10-9m) and possesses higher thermal properties. They are widely utilized in different applications, like in energy, construction, biomedical, chemical, electronics, agriculture, cosmetics, etc. This chapter deals with the application of nanocomposites (SiC/Al2O3/B4C/TiO2/ZnO/SiO2) in the field of energy applications by analyzing their properties (thermal-conductivity/density/specific-heat) using numerical models. The effect of nanoparticles reinforced wt. % concentration into a base material (Al6061/Al7075/H2O) is also analyzed. Results show that nanocomposites have higher effective thermal conductivity and are suitable for high heat-releasing energy devices. It is found that the addition of nanoparticles increases the surface area to volume ratio, which further increases the energy transfer rate. Results show that nanocomposites with lower effective density are suitable when there is a requirement of reduction in weight for the same heat release application.

Numerical Study of Nanocomposites for Energy Applications

2021 ◽  
pp. 656-684
Author(s):  
Siddhartha Kosti
Keyword(s):  
Thermal Conductivity ◽  
Numerical Study ◽  
Numerical Models ◽  
Base Material ◽  
Volume Ratio ◽  
High Heat ◽  
Effective Density ◽  
Energy Transfer Rate ◽  
Energy Devices ◽  
Energy Applications

Nanocomposites are defined as a combination of nanoparticles reinforced into the base material. They are of very small sizes (1nm = 10-9m) and possesses higher thermal properties. They are widely utilized in different applications, like in energy, construction, biomedical, chemical, electronics, agriculture, cosmetics, etc. This chapter deals with the application of nanocomposites (SiC/Al2O3/B4C/TiO2/ZnO/SiO2) in the field of energy applications by analyzing their properties (thermal-conductivity/density/specific-heat) using numerical models. The effect of nanoparticles reinforced wt. % concentration into a base material (Al6061/Al7075/H2O) is also analyzed. Results show that nanocomposites have higher effective thermal conductivity and are suitable for high heat-releasing energy devices. It is found that the addition of nanoparticles increases the surface area to volume ratio, which further increases the energy transfer rate. Results show that nanocomposites with lower effective density are suitable when there is a requirement of reduction in weight for the same heat release application.

scholarly journals Nanoporous Metallic Films

2021 ◽  
Author(s):  
Swastic ◽  
Jegatha Nambi Krishnan
Keyword(s):  
Thermal Conductivity ◽  
High Surface ◽  
Volume Ratio ◽  
Metallic Films ◽  
Top Down ◽  
Drug Delivery Vehicles ◽  
Energy Applications ◽  
Potential Applications ◽  
Current Scenario ◽  
Delivery Vehicles

Nanoporous metallic films are known to have high surface to volume ratio due to the presence of pores. The presence of pores and ligaments make them suitable for various critical applications like sensing, catalysis, electrodes for energy applications etc. Additionally, they also combine properties of metals like good electrical and thermal conductivity and ductility. They can be fabricated using top-down or bottom-up approaches also known as dealloying and templating which give the fabricator room to tailor properties according to need. In addition, they could find potential applications in many relevant fields in current scenario like drug delivery vehicles. However, there is a long way to go to extract its whole potential.

Investigation of Properties of Diesel Fuel and Carbon Nanotubes Mixture and Characteristics of its Atomization

2021 ◽  
pp. 48-64
Author(s):  
Bowen Sa ◽  
V.A. Markov ◽  
Ying Liu ◽  
V.G. Kamaltdinov ◽  
Wenpei Qiao
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Diesel Fuel ◽  
Numerical Models ◽  
Volume Ratio ◽  
Fuel Vapor ◽  
Data Simulation ◽  
Constant Volume Combustion Chamber ◽  
Research Show ◽  
Good Agreement

The fuel economy and exhaust emissions of diesel engines can be improved by adding carbon nanotubes to petroleum diesel fuel. Carbon nanotubes, used as a promising nanoscale additive for diesel fuel, have high thermal conductivity and a large surface area to volume ratio. The thermophysical properties of these fuels, which depend on the composition of the mixtures, are analyzed in this study. Findings of research show that carbon nanotubes added to diesel fuel have little effect on its dynamic viscosity and thermal conductivity. By means of numerical models, we simulated the process of atomization and evaporation of diesel fuel with the different carbon nanotubes content in a constant volume combustion chamber. The accuracy of the calculations is confirmed by the good agreement between the calculated and experimental data. Simulation of mixture atomization showed that the jet length linearly depends on the carbon nanotubes content in diesel fuel. The more carbon nanotubes are in the mixture, the smaller the droplet Sauter mean diameter and the angle of the jet cone opening are. The presence of carbon nanotubes in diesel fuel insignificantly affects the fuel vapor content in it.

Thermal Performance of Natural Graphite Heat Spreaders With Embedded Thermal Vias

2007 ◽  
Author(s):  
Martin Smalc ◽  
Prathib Skandakumaran ◽  
Julian Norley
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Thermal Performance ◽  
Numerical Models ◽  
Accelerated Aging ◽  
High Heat ◽  
High Heat Flux ◽  
Natural Graphite ◽  
Heat Spreaders ◽  
Graphite Heat

Natural graphite heat spreaders are in use in electronic cooling applications where heat flux density is low. Natural graphite is an anisotropic material, with a high thermal conductivity in the plane of the spreader combined with a much lower thermal conductivity through its thickness. This low through-thickness thermal conductivity poses a problem when attempting to cool heat sources with relatively high heat flux densities. This problem can be overcome by embedding a thermal via in the graphite material. This via is made from an isotropic material with a thermal conductivity significantly higher than the through-thickness graphite conductivity. This paper examines the thermal performance of a natural graphite heat spreader with an embedded thermal via. The work is primarily experimental although numerical models were used to guide the experiments. The thermal performance of these spreaders is compared to that of spreaders made from conventional isotropic materials. The effect of accelerated aging tests on the performance of these graphite spreaders is reviewed. Finally, two applications are examined; first cooling an ASIC module and second, cooling an FB-DIMM memory card.

Evaluation of Turbulence Models for the Numerical Study of Reciprocating-Mechanism Driven Heat Loop

2016 ◽  
Author(s):  
Olubunmi T. Popoola ◽  
Ayobami A. Bamgbade ◽  
Y. Cao
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Numerical Study ◽  
Numerical Models ◽  
Turbulence Models ◽  
Boussinesq Approximation ◽  
High Heat ◽  
Working Fluid ◽  
High Heat Transfer ◽  
Transfer Device

A bellows-type Reciprocating-Mechanism Driven Heat Loops (RMDHL) is a novel heat transfer device that could attain a high heat transfer rate through a reciprocating flow of the working fluid inside the heat transfer device. Although the device has been tested and validated experimentally, analytical or numerical study have not been undertaken to understand its working mechanism and to provide guidance for the device design. In a bid to improve the accuracy of the numerical models of the RMDHL, seven turbulence models for fluid flow have been alternately adapted and implemented in an existing numerical RMDHL model. The obtained results were studied and compared with prior experimental results to gain confidence and select the most suitable turbulence modeling techniques. The Boussinesq approximation has been used and the governing equations have been numerically solved using the CFD solver FLUENT. For the three-dimensional fluid flow, the turbulence models were studied are the Standard, RNG, and Realizable k-ε Models, Standard and SST k-ω Models, Transition k-kL-ω Model and the Transition SST Model. The result of each numerical simulation have been analyzed and ranked using a numerical model calibration template. It was found that the standard k-ω Models provided the least accurate results while the RNG-k-ε Model provided the most accurate predictions. It is expected that the results will help improve the accuracy of the work on the RMDHL modeling.

Effective thermal conductivity of open-pore metal foams as a function of the base material

2015 ◽  
Vol 57 (10) ◽  
pp. 825-836 ◽  
Author(s):  
Alexander Martin Matz ◽  
Bettina Stefanie Mocker ◽  
Norbert Jost ◽  
Peter Krug
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Base Material ◽  
Metal Foams

Electrochemical Deposition of Polypyrrole Nanostructures for Energy Applications: A Review

2020 ◽  
Vol 16 (4) ◽  
pp. 462-477 ◽  
Author(s):  
Patrizia Bocchetta ◽  
Domenico Frattini ◽  
Miriana Tagliente ◽  
Filippo Selleri
Keyword(s):  
Lithium Batteries ◽  
High Performance ◽  
Relevant Literature ◽  
Chemical Parameters ◽  
Energy Devices ◽  
Energy Applications ◽  
Physico Chemical ◽  
Potential Applications ◽  
Template Free ◽  
Cathodic Polymerization

By collecting and analyzing relevant literature results, we demonstrate that the nanostructuring of polypyrrole (PPy) electrodes is a crucial strategy to achieve high performance and stability in energy devices such as fuel cells, lithium batteries and supercapacitors. In this critic and comprehensive review, we focus the attention on the electrochemical methods for deposition of PPy, nanostructures and potential applications, by analyzing the effect of different physico-chemical parameters, electro-oxidative conditions including template-based or template-free depositions and cathodic polymerization. Diverse interfaces and morphologies of polymer nanodeposits are also discussed.

scholarly journals Design of Thermal Insulation Materials with Different Geometries of Channels

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2217
Author(s):  
Daniela Șova ◽  
Mariana Domnica Stanciu ◽  
Sergiu Valeriu Georgescu
Keyword(s):  
Thermal Conductivity ◽  
Porous Structure ◽  
Base Material ◽  
Cost Effective ◽  
Heat Radiation ◽  
Average Temperature ◽  
Temperature Regimes ◽  
The Face ◽  
Inclined Channels ◽  
Air Channels

Investigating the large number of various materials now available, some materials scientists promoted a method of combining existing materials with geometric features. By studying natural materials, the performance of simple constituent materials is improved by manipulating their internal geometry; as such, any base material can be used by performing millimeter-scale air channels. The porous structure obtained utilizes the low thermal conductivity of the gas in the pores. At the same time, heat radiation and gas convection is hindered by the solid structure. The solution that was proposed in this research for obtaining a material with porous structure consisted in perforating extruded polystyrene (XPS) panels, as base material. Perforation was performed horizontally and at an angle of 45 degrees related to the face panel. The method is simple and cost-effective. Perforated and simple XPS panels were subjected to three different temperature regimes in order to measure the thermal conductivity. There was an increase in thermal conductivity with the increase in average temperature in all studied cases. The presence of air channels reduced the thermal conductivity of the perforated panels. The reduction was more significant at the panels with inclined channels. The differences between the thermal conductivity of simple XPS and perforated XPS panels are small, but the latter can be improved by increasing the number of channels and the air channels’ diameter. Additionally, the higher the thermal conductivity of the base material, the more significant is the presence of the channels, reducing the effective thermal conductivity. A base material with low emissivity may also reduce the thermal conductivity.

scholarly journals Anion ordering enables fast H− conduction at low temperatures

2021 ◽  
Vol 7 (23) ◽  
pp. eabf7883
Author(s):  
Hiroki Ubukata ◽  
Fumitaka Takeiri ◽  
Kazuki Shitara ◽  
Cédric Tassel ◽  
Takashi Saito ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Room Temperature ◽  
Structural Transition ◽  
Hexagonal Lattice ◽  
Ionic Conductors ◽  
Activation Barriers ◽  
Energy Devices ◽  
Energy Applications ◽  
Chemical Disorder ◽  
New Energy

The introduction of chemical disorder by substitutional chemistry into ionic conductors is the most commonly used strategy to stabilize high-symmetric phases while maintaining ionic conductivity at lower temperatures. In recent years, hydride materials have received much attention owing to their potential for new energy applications, but there remains room for development in ionic conductivity below 300°C. Here, we show that layered anion-ordered Ba2−δH3−2δX (X = Cl, Br, and I) exhibit a remarkable conductivity, reaching 1 mS cm−1 at 200°C, with low activation barriers allowing H− conduction even at room temperature. In contrast to structurally related BaH2 (i.e., Ba2H4), the layered anion order in Ba2−δH3−2δX, along with Schottky defects, likely suppresses a structural transition, rather than the traditional chemical disorder, while retaining a highly symmetric hexagonal lattice. This discovery could open a new direction in electrochemical use of hydrogen in synthetic processes and energy devices.

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