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.

Temperature and Viscosity Effects on the Thermal Conductivity of Ferro-Nanofluid

2009 ◽  
Author(s):  
Chin-Ting Yang ◽  
Shao-Hua Cheng
Keyword(s):  
Thermal Conductivity ◽  
Brownian Motion ◽  
Diesel Fuel ◽  
Base Fluid ◽  
Volume Fraction ◽  
Volume Ratio ◽  
Polydimethyl Siloxane ◽  
Viscosity Effects ◽  
Lower Viscosity ◽  
Lower Temperature

The aim of this study is to understand the temperature and viscosity effects on the thermal conductivity of ferro-nanofluid. The base-fluid of ferro-nanofluid is made of polydimethyl-siloxane (PDMS) and diesel fuel which have similar thermal property but different viscosity. The viscosity of base-fluid is controlled by changing the volume ratio of both fluids. The measured results show that the thermal conductivity is smaller when the base fluid is highly viscous, and the thermal conductivity approaches to the value predicted by the Maxwell equation. It should be that the Brownian motion effect on highly viscous fluid is not as important as on lower viscosity fluid. Usually rising temperature will decrease viscosity of base fluid. In our study, rising temperature to 58°C can reduce the viscosity of 90%diesel fuel+10%PDMS to pure diesel fuel base fluid at 23 °C. At the same viscosity condition, rising temperature will decrease the thermal conductivity of ferro-nanofluid. The reason is that the thermal conductivity of base-fluid decrease dramatically. Comparing thermal conductivity of 2% volume fraction ferro-nanofluid to base-fluid at 23°C and 58°C respectively, the value increases 8.3% at 23 °C but increases 18.8% when the temperature is 58°C. This means the Brownian motion is more active at higher temperature than lower temperature.

Effect of the Carbon Nanotube Distribution on the Thermal Conductivity of Composite Materials

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Iman Eslami Afrooz ◽  
Andreas Öchsner
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Finite Element Analysis ◽  
Composite Materials ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Volume ◽  
Element Analysis ◽  
The Matrix ◽  
Good Agreement

Finite element analysis has been employed to investigate the effect of carbon nanotubes (CNTs) distribution on the thermal conductivity of composite materials. Several kinds of representative volume elements (RVEs) employed in this study are made by assuming that unidirectional CNTs are randomly distributed in a polymer matrix. It is also assumed that each set of RVEs contains a constant fiber volume fraction and aspect ratio. Results show that randomness—the way in which fibers are distributed inside the matrix—has a significant effect on the thermal conductivity of CNT composites. Results of this study were compared using the analytical Xue and Nan model and good agreement was observed.

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 Experimental and numerical investigation of thermal improvement of window frames

2020 ◽  
pp. 189-189
Author(s):  
Milan Gojak ◽  
Aleksandar Kijanovic ◽  
Nedzad Rudonja ◽  
Ruzica Todorovic
Keyword(s):  
Thermal Conductivity ◽  
Numerical Models ◽  
Wooden Frame ◽  
Thermal Transmittance ◽  
Different Types ◽  
Thermal Improvement ◽  
Air Cavities ◽  
Glass Unit ◽  
Good Agreement ◽  
Window Frames

In this article are presented experimental and numerical determinations of thermal transmittance performed on three different types of window frames (vinyl, aluminium and wooden) within the same insulated glass unit. Good agreement between experimental and numerical results was attained. Using the numerical models, thermal improvement techniques of the frames and their influence on thermal transmittance of frames were studied. The first thermal improvement technique was using the insulation materials inserted inside large air cavities. By filling the cavity of vinyl frame with the polyurethane foam, thermal transmittance of vinyl frame was lowered by 10%. The second technique was based on repeating the procedure with materials installed inside frames with the materials that have lower thermal conductivity. This technique can be applied on thermal breaks and on steel profiles inside cavities. The result of this thermal improvement (attained by replacing thermal break material with material that has lower thermal conductivity) was certain reduction of the thermal transmittance of frames, by 9%. Using stainless steel instead of the oxidized steel was reduction of the thermal transmittance of vinyl frame by 3%. For the case of wooden frames was analysed the influence of shifting glazing unit deeper into profile upon the thermal transmittance of the frame. Installing the glass unit by 5 mm deeper into the wooden frame reduced glass thermal transmittance by 5%.

A model for thermal conductivity of carbon nanotubes with ethylene glycol/water based nanofluids

2017 ◽  
Vol 59 (02) ◽  
pp. 10-13
Author(s):  
Trong Tam Nguyen ◽  
◽  
Hung Thang Bui ◽  
Ngoc Minh Phan ◽  
◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Ethylene Glycol ◽  
Water Based

scholarly journals Macroscopic weavable fibers of carbon nanotubes with giant thermoelectric power factor

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Natsumi Komatsu ◽  
Yota Ichinose ◽  
Oliver S. Dewey ◽  
Lauren W. Taylor ◽  
Mitchell A. Trafford ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Thermoelectric Power ◽  
Power Factor ◽  
Fermi Energy ◽  
Performance Enhancement ◽  
Thermoelectric Performance ◽  
Thermoelectric Power Factor ◽  
Large Power ◽  
Energy Tuning

AbstractLow-dimensional materials have recently attracted much interest as thermoelectric materials because of their charge carrier confinement leading to thermoelectric performance enhancement. Carbon nanotubes are promising candidates because of their one-dimensionality in addition to their unique advantages such as flexibility and light weight. However, preserving the large power factor of individual carbon nanotubes in macroscopic assemblies has been challenging, primarily due to poor sample morphology and a lack of proper Fermi energy tuning. Here, we report an ultrahigh value of power factor (14 ± 5 mW m−1 K−2) for macroscopic weavable fibers of aligned carbon nanotubes with ultrahigh electrical and thermal conductivity. The observed giant power factor originates from the ultrahigh electrical conductivity achieved through excellent sample morphology, combined with an enhanced Seebeck coefficient through Fermi energy tuning. We fabricate a textile thermoelectric generator based on these carbon nanotube fibers, which demonstrates high thermoelectric performance, weavability, and scalability. The giant power factor we observe make these fibers strong candidates for the emerging field of thermoelectric active cooling, which requires a large thermoelectric power factor and a large thermal conductivity at the same time.

scholarly journals Thermoelectric Materials for Textile Applications

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3154
Author(s):  
Kony Chatterjee ◽  
Tushar K. Ghosh
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Inorganic Materials ◽  
Peltier Effect ◽  
Electronic Textiles ◽  
Heating And Cooling ◽  
Recent Attention

Since prehistoric times, textiles have served an important role–providing necessary protection and comfort. Recently, the rise of electronic textiles (e-textiles) as part of the larger efforts to develop smart textiles, has paved the way for enhancing textile functionalities including sensing, energy harvesting, and active heating and cooling. Recent attention has focused on the integration of thermoelectric (TE) functionalities into textiles—making fabrics capable of either converting body heating into electricity (Seebeck effect) or conversely using electricity to provide next-to-skin heating/cooling (Peltier effect). Various TE materials have been explored, classified broadly into (i) inorganic, (ii) organic, and (iii) hybrid organic-inorganic. TE figure-of-merit (ZT) is commonly used to correlate Seebeck coefficient, electrical and thermal conductivity. For textiles, it is important to think of appropriate materials not just in terms of ZT, but also whether they are flexible, conformable, and easily processable. Commercial TEs usually compromise rigid, sometimes toxic, inorganic materials such as bismuth and lead. For textiles, organic and hybrid TE materials are more appropriate. Carbon-based TE materials have been especially attractive since graphene and carbon nanotubes have excellent transport properties with easy modifications to create TE materials with high ZT and textile compatibility. This review focuses on flexible TE materials and their integration into textiles.

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