A New Type of Nanoengineered Heat Transfer Fluids: Nanoemulsion Fluids

2006 ◽  
Author(s):  
Bao Yang ◽  
Zenghu Han
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Solid Particles ◽  
Long Term Stability ◽  
Heat Transfer Fluids ◽  
Thermal Fluids ◽  
New Type ◽  
Improved Performance ◽  
Novel Concept

Thermal management in the next decade of microelectronics and optoelectronics will require heat transfer fluids with improved performance over those currently available. The strategy of adding SOLID particles to fluids for improving thermal conductivity has been pursued for nearly a century. In this work, a novel concept of using LIQUID nanodroplets for enhancing thermal conductivity has been developed and was experimentally-demonstrated in water-in-FC72 suspensions, called "nanoemulsion-fluids". The thermal conductivity of FC72 is found to be increased by up to 52% for a nanoemulsion-fluid containing 12vol% water nanodroplets of radius 9.8nm. Such types of nanoemulsion-fluids possess long-term stability and can be mass produced because of no needs for SOLID nanoparticles. The development of nanoemulsion-fluids would open a new direction for thermal fluids studies.

scholarly journals Thermal Conductivity of Nanofluids: A Review on Prediction Models, Controversies and Challenges

2021 ◽  
Vol 11 (6) ◽  
pp. 2525
Author(s):  
Inês Gonçalves ◽  
Reinaldo Souza ◽  
Gonçalo Coutinho ◽  
João Miranda ◽  
Ana Moita ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Machine Learning ◽  
Thermal Conductivity ◽  
Prediction Models ◽  
Statistical Machine Learning ◽  
Fundamental Parameters ◽  
Long Term Stability ◽  
Heat Transfer Fluids ◽  
Classical Models

In recent years, the nanofluids (NFs) have become the main candidates for improving or even replacing traditional heat transfer fluids. The possibility of NFs to be used in various technological applications, from renewable energies to nanomedicine, has made NFs and their thermal conductivity one of the most studied topics nowadays. Hence, this review presents an overview of the most important advances and controversial results related to the NFs thermal conductivity. The different techniques used to measure the thermal conductivity of NFs are discussed. Moreover, the fundamental parameters that affect the NFs thermal conductivity are analyzed, and possible improvements are addressed, such as the increase of long-term stability of the nanoparticles (NPs).The most representative prediction classical models based on fluid mechanics, thermodynamics, and experimental fittings are presented. Also, the recent statistical machine learning-based prediction models are comprehensively addressed, and the comparison with the classical empirical ones is made, whenever possible.

A Review of Preparation and Tribological Applications of Pickering Emulsion

2021 ◽  
pp. 1-27
Author(s):  
Yichen Bao ◽  
Kai Liu ◽  
Quan Zheng ◽  
Lulu Yao ◽  
Yufu Xu
Keyword(s):  
Pickering Emulsion ◽  
Solid Particles ◽  
Preparation Methods ◽  
Factors Affecting ◽  
Long Term Stability ◽  
New Strategy ◽  
New Type ◽  
The Stability ◽  
Near Future

Abstract Pickering emulsion is a new type of stable emulsion made by ultra-fine solid particles instead of traditional surfactants as stabilizers, which has received widespread attention in recent years. The preparation methods of stator-rotor homogenization, high-pressure homogenization, and ultrasonic emulsification were compared with others in this work. The main factors affecting the stability of Pickering emulsion are the surface humidity of the solid particles, the polarity of the oil phase, and the oil-water ratio. These factors could affect the nature of the solid particles, the preparation process of Pickering emulsion and the external environment. Consequently, the long-term stability of Pickering emulsion is still a challenge. The tribological investigations of Pickering emulsion were summarized, and the multifunctional Pickering emulsion shows superior prospects for tribological applications. Moreover, the latest development of Pickering emulsion offers a new strategy for smart lubrication in the near future.

scholarly journals AL2O3 Nanofluids as Heat Transfer Liquids in Automotives

2014 ◽  
pp. 206-212
Author(s):  
M. YASASWI ◽  
R.V. PRASAD ◽  
T.JAYANDA KUMAR
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Energy Efficient ◽  
Solid Particles ◽  
Al2o3 Nanoparticles ◽  
Particle Volume ◽  
Heat Transfer Fluids ◽  
Potential Impact ◽  
Efficient Heat Transfer

The thermal conductivity of heating or cooling fluids is a very important property in the development of energy efficient heat transfer systems, which is one of the important needs of many industries. However, low thermal conductivity is a primary limitation in developing energy-efficient heat transfer fluids that are required for cooling purposes. Nanofluids are nanotechnology-based heat transfer fluids that are engineered by stably dispersing nanometer-sized (below 100nm) solid particles (such as ceramics, metals, alloys, semiconductors, nanotubes, and composite particles) in conventional heat transfer fluids (such as water, oil, diesel, ethylene glycol and mixtures) at relatively low particle volume concentrations. These suspended nanoparticles can change the transport and thermal properties of the base fluid. Adding to ethylene glycol, it has been observed that an enhancement of nearly 36 % with al2o3 nanoparticles and 40% enhancement with copper nanoparticles in the thermal conductivity. This paper focuses on some of the automotive applications such as coolant for automobiles, showcases a few of them that are believed to have the highest probability of success in this highly competitive industry and to raise the awareness on the promise of nanotechnology, its potential impact on the future of the automotive industry.

Analytical Technique for Estimating the Termophysical Properties of Hybrid Nanofluids

2017 ◽  
Vol 1143 ◽  
pp. 207-213
Author(s):  
Madalina Georgiana Moldoveanu ◽  
Tudor Mihai Simionescu ◽  
Alina Adriana Minea ◽  
Adrian Dima
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
High Performance ◽  
Solid Particles ◽  
Drilling Fluids ◽  
Distilled Water ◽  
Worst Case ◽  
Analytical Technique ◽  
Heat Transfer Fluids ◽  
High Concentrations

Over the past years, the development of functional heat transfer fluids by compounding different substances or different phases of matter (solid, liquid, or gas) has raised increasing interest in view of their potential applications in technologies. In particular, the nanofluids in which the solid particles (<100 nm or smaller) are incorporated as the dispersed phase in the suspensions, are currently focus of great attention because of their perspective potentials as high-performance heat transfer fluids. The potential advantage of utilizing the nanofluid lies mainly in its drastic increase in the thermal conductivity. This paper presents a study of the thermophysical characteristics of some nanofluids and their hybrids. General correlations for the effective thermal conductivity and viscosity of nanofluids are used for this analysis. Regarding the importance of thermophysical properties of water based drilling fluids, the effects of insertion of two oxides in an alumina-water nanofluid on the thermal conductivity, viscosity and density of distilled water were investigated. According to the results, viscosity and density of the nanofluids increased with the concentration. At high concentrations, the least increase in the viscosity of distilled water by adding the nanomaterials is related to H2 (8.2% increase at 1.0 wt.%). As the results show, increase in the density of distilled water by adding the nanomaterials is insignificant, that in the worst case it did not exceed 0.9%. The least increase in the density of base fluid at high concentrations was for H1.

scholarly journals State of the Art in PEG-Based Heat Transfer Fluids and Their Suspensions with Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 86
Author(s):  
Alina Adriana Minea
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Polyethylene Glycol ◽  
Phase Change ◽  
Phase Change Materials ◽  
State Of The Art ◽  
Short Review ◽  
Numerical Work ◽  
Heat Transfer Fluids ◽  
Improved Performance

Research on nanoparticle enhanced fluids has increased rapidly over the last decade. Regardless of several unreliable reports, these new fluids have established performance in heat transfer. Lately, polyethylene glycol with nanoparticles has been demarcated as an innovative class of phase change materials with conceivable uses in the area of convective heat transfer. The amplified thermal conductivity of these nanoparticle enhanced phase change materials (PCMs) over the basic fluids (e.g., polyethylene glycol—PEG) is considered one of the driving factors for their improved performance in heat transfer. Most of the research, however, is centered on the thermal conductivity discussion and less on viscosity variation, while specific heat capacity seems to be fully ignored. This short review abridges most of the recent investigations on new PEG-based fluids and is dedicated especially to thermophysical properties of the chemicals, while a number of PEG-based nanofluids are compared in terms of base fluid and/or nanoparticle type and concentration. This review outlines the possibility of developing promising new heat transfer fluids. To conclude, this research is in its pioneering phase, and a large amount of experimental and numerical work is required in the coming years.

Pool Boiling Characteristics of Metallic Nanofluids

2011 ◽  
Vol 133 (11) ◽  
Author(s):  
K. Hari Krishna ◽  
Harish Ganapathy ◽  
G. Sateesh ◽  
Sarit K. Das
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Boiling Heat Transfer ◽  
Volume Fraction ◽  
Pool Boiling ◽  
Heat Fluxes ◽  
Solid Particles ◽  
Heater Surface ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Nanofluids, solid-liquid suspensions with solid particles of size of the order of few nanometers, have created interest in many researchers because of their enhancement in thermal conductivity and convective heat transfer characteristics. Many studies have been done on the pool boiling characteristics of nanofluids, most of which have been with nanofluids containing oxide nanoparticles owing to the ease in their preparation. Deterioration in boiling heat transfer was observed in some studies. Metallic nanofluids having metal nanoparticles, which are known for their good heat transfer characteristics in bulk regime, reported drastic enhancement in thermal conductivity. The present paper investigates into the pool boiling characteristics of metallic nanofluids, in particular of Cu-H2O nanofluids, on flat copper heater surface. The results indicate that at comparatively low heat fluxes, there is deterioration in boiling heat transfer with very low particle volume fraction of 0.01%, and it increases with volume fraction and shows enhancement with 0.1%. However, the behavior is the other way around at high heat fluxes. The enhancement at low heat fluxes is due to the fact that the effect of formation of thin sorption layer of nanoparticles on heater surface, which causes deterioration by trapping the nucleation sites, is overshadowed by the increase in microlayer evaporation, which is due to enhancement in thermal conductivity. Same trend has been observed with variation in the surface roughness of the heater as well.

Study of thermal conductivity of nanofluids for the application of heat transfer fluids

2007 ◽  
Vol 455 (1-2) ◽  
pp. 66-69 ◽  
Author(s):  
Dae-Hwang Yoo ◽  
K.S. Hong ◽  
Ho-Soon Yang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Fluids

scholarly journals Implicit Finite Difference Simulation of Prandtl-Eyring Nanofluid over a Flat Plate with Variable Thermal Conductivity: A Tiwari and Das Model

Mathematics ◽  
2021 ◽  
Vol 9 (24) ◽  
pp. 3153
Author(s):  
Nidal H. Abu-Hamdeh ◽  
Abdulmalik A. Aljinaidi ◽  
Mohamed A. Eltaher ◽  
Khalid H. Almitani ◽  
Khaled A. Alnefaie ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Finite Difference ◽  
Differential Equations ◽  
Ordinary Differential Equations ◽  
Variable Thermal Conductivity ◽  
Solid Particles ◽  
Engine Oil ◽  
Working Fluid ◽  
Implicit Finite Difference

The current article presents the entropy formation and heat transfer of the steady Prandtl-Eyring nanofluids (P-ENF). Heat transfer and flow of P-ENF are analyzed when nanofluid is passed to the hot and slippery surface. The study also investigates the effects of radiative heat flux, variable thermal conductivity, the material’s porosity, and the morphologies of nano-solid particles. Flow equations are defined utilizing partial differential equations (PDEs). Necessary transformations are employed to convert the formulae into ordinary differential equations. The implicit finite difference method (I-FDM) is used to find approximate solutions to ordinary differential equations. Two types of nano-solid particles, aluminium oxide (Al2O3) and copper (Cu), are examined using engine oil (EO) as working fluid. Graphical plots are used to depict the crucial outcomes regarding drag force, entropy measurement, temperature, Nusselt number, and flow. According to the study, there is a solid and aggressive increase in the heat transfer rate of P-ENF Cu-EO than Al2O3-EO. An increment in the size of nanoparticles resulted in enhancing the entropy of the model. The Prandtl-Eyring parameter and modified radiative flow show the same impact on the radiative field.

Heat Transfer Properties of Engine Oils

2005 ◽  
Author(s):  
Scott Wrenick ◽  
Paul Sutor ◽  
Harold Pangilinan ◽  
Ernest E. Schwarz
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Diesel Engine ◽  
Specific Heat ◽  
Mineral Oil ◽  
Engine Oil ◽  
Group V ◽  
Engine Oils ◽  
Heat Transfer Fluids ◽  
Transfer Properties

The thermal properties of engine oil are important traits affecting the ability of the oil to transfer heat from the engine. The larger the thermal conductivity and specific heat, the more efficiently the oil will transfer heat. In this work, we measured the thermal conductivity and specific heat of a conventional mineral oil-based diesel engine lubricant and a Group V-based LHR diesel engine lubricant as a function of temperature. We also measured the specific heat of ethylene glycol. The measured values are compared with manufacturers’ data for typical heat transfer fluids. The Group V-based engine oil had a higher thermal conductivity and slightly lower specific heat than the mineral oil-based engine oil. Both engine oils had values comparable to high-temperature heat transfer fluids.

Analysis of nanofluids as a means of thermal conductivity enhancement in heavy machineries

2014 ◽  
Vol 66 (2) ◽  
pp. 238-243 ◽  
Author(s):  
Ayush Jain ◽  
Imbesat Hassan Rizvi ◽  
Subrata Kumar Ghosh ◽  
P.S. Mukherjee
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Base Fluid ◽  
High Concentration ◽  
Content Type ◽  
Conductivity Enhancement ◽  
Heavy Machinery ◽  
Heat Transfer Fluids ◽  
Experimental Findings

Purpose – Nanofluids exhibit enhanced heat transfer characteristics and are expected to be the future heat transfer fluids particularly the lubricants and transmission fluids used in heavy machinery. For studying the heat transfer behaviour of the nanofluids, precise values of their thermal conductivity are required. For predicting the correct value of thermal conductivity of a nanofluid, mathematical models are necessary. In this paper, the effective thermal conductivity of various nanofluids has been reported by using both experimental and mathematical modelling. The paper aims to discuss these issues. Design/methodology/approach – Hamilton and Crosser equation was used for predicting the thermal conductivities of nanofluids, and the obtained values were compared with the experimental findings. Nanofluid studied in this paper are Al2O3 in base fluid water, Al2O3 in base fluid ethylene glycol, CuO in base fluid water, CuO in base fluid ethylene glycol, TiO2 in base fluid ethylene glycol. In addition, studies have been made on nanofluids with CuO and Al2O3 in base fluid SAE 30 particularly for heavy machinery applications. Findings – The study shows that increase in thermal conductivity of the nanofluid with particle concentration is in good agreement with that predicted by Hamilton and Crosser at typical lower concentrations. Research limitations/implications – It has been observed that deviation between experimental and theoretical results increases as the volume concentration of nanoparticles increases. Therefore, the mathematical model cannot be used for predicting thermal conductivity at high concentration values. Originality/value – Studies on nanoparticles with a standard mineral oil as base fluid have not been considered extensively as per the previous literatures available.

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