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.

Thermal Conductivity Enhancement by Adding Nanoparticles to Ionic Liquids

2017 ◽  
Vol 261 ◽  
pp. 121-126 ◽  
Author(s):  
Alina Adriana Minea ◽  
Madalina Georgiana Moldoveanu ◽  
Oana Dodun
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Thermophysical Properties ◽  
Base Fluid ◽  
Thermal Conductivity Enhancement ◽  
Conductivity Enhancement ◽  
New Class ◽  
Enhanced Thermal Conductivity

Ionanofluids are a very new class of nanofluids having ionic liquids as the base fluid. Thermophysical properties of base ionic liquids (ILs) and nanoparticle enhanced ionic liquids (NEILs) are part of studying a new class of fluids for heat transfer. NEILs are formed by dispersing different volume fractions of nanoparticles in a base ionic liquid. In this article, only the thermal conductivity enhancement was considered for comparison of the different ionanofluids. NEILs show enhanced thermal conductivity compared to the base ILs. Maximum thermal conductivity enhancement was observed by adding 1 % MWCNT to [C4mim][(CF3SO2)2N] ionic liquid. However, if 0.05% MWCNT are added to [(C6)3PC14)][NTf2] no enhancement in thermal conductivity was noticed.

Thermal Conductivity Enhancement of Room Temperature Ionic Liquids (RTILs) With Various Magnetic Nanoparticles

2012 ◽  
Author(s):  
N. Y. Jagath B. Nikapitiya ◽  
Hyejin Moon
Keyword(s):  
Thermal Conductivity ◽  
Ionic Liquids ◽  
Magnetic Nanoparticles ◽  
Magnetic Fields ◽  
Room Temperature ◽  
Particle Concentration ◽  
Thermal Conductivity Enhancement ◽  
Room Temperature Ionic Liquids ◽  
Conductivity Enhancement ◽  
Magnetic Nanofluids

This paper reports an experimental study of thermal conductivity of room temperature ionic liquids (RTILs) based magnetic nanofluids. Various magnetic nanoparticles of metal oxides with high thermal conductivity, such as CuO, Al2O3, Fe3O4 and Carbon Nano Tubes (CNTs), were used to prepare magnetic nanofluids, while RTIL, trihexyl (tetradecyl) posphonium dicyanamide was used as the base fluid. Two major parameters that affect to the thermal conductivity enhancement of fluids were investigated. The effect of particle concentration and external magnetic fields were tested. It was observed that the magnetic nanofluids thermal conductivities increase with increment of particle concentration and external magnetic field parallel to the temperature gradient. Besides, it was observed that under higher magnetic fields, thermal conductivity enhancement tends to approach a saturation state. Surfactant was used to disperse magnetic nanoparticles within the RTILs. The transient hot wire method was used for this investigation.

Thermal Conductivity Enhancement of Aluminium Oxide Nanofluid in Ethylene Glycol

2014 ◽  
Vol 660 ◽  
pp. 730-734 ◽  
Author(s):  
Khamisah Abdul Hamid ◽  
Wan Hamzah Azmi ◽  
Rizalman Mamat ◽  
Nur Ashikin Usri
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Properties ◽  
Ethylene Glycol ◽  
Volume Concentration ◽  
Conductivity Measurement ◽  
Thermal Conductivity Enhancement ◽  
Heat Transfer Fluid ◽  
Coolant Fluid ◽  
Conductivity Enhancement

Nanofluids are the new coolant fluid that has been widely investigates due to its ability to improved heat transfer better than conventional heat transfer fluid. The need to study the nanofluid properties has been increased to provide better understanding on nanofluid thermal properties and behavior. This study presents the measurement analysis on thermal conductivity enhancement of Al2O3 nanoparticles dispersed in ethylene glycol. The nanofluids are prepared using two step method for volume concentration range from 1.0 % to 4.0 %. The thermal conductivity measurement of the nanofluid is performed by KD2 Pro Thermal Properties Analyzer at working temperature range from 30 °C to 80 °C. The maximum enhancement in thermal conductivity is 21.1 % at volume concentration of 2.0 % and temperature of 70 °C. The results show that the thermal conductivity increases with the increase of nanofluid concentration and temperature. Also, the nanofluid shows enhancement in thermal conductivity compare to the base fluid.

scholarly journals Ultrasonic and thermophysical studies of ethylene glycol nanofluids containing TiO2 nanoparticles and their heat transfer enhancements

2020 ◽  
Author(s):  
Mohit Gupta ◽  
Devraj Singh ◽  
Shakti Pratap Singh ◽  
Ashish Mathur ◽  
Shikha Wadhwa ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Tio2 Nanoparticles ◽  
Ultrasonic Velocity ◽  
Base Fluid ◽  
Sol Gel ◽  
Interaction Force ◽  
Thermal Conductivity Enhancement ◽  
Conductivity Enhancement

In present investigation, TiO2 nanostructures were synthesized via simple sol-gel technique and characterized with XRD, SEM-EDX, HRTEM and UV-visible spectroscopy techniques. The temperature and concentration dependence of thermal conductivity enhancement and ultrasonic velocity have been explored in ethylene glycol (EG)-based TiO2 nanofluids. The obtained results showed 24% enhancement in thermal conductivity at higher temperature (80°C) of base fluid ethylene glycol by adding 1.0 wt.% of TiO2 nanoparticles. The behaviour of thermal conductivity enhancement and ultrasonic velocity with temperature in prepared nanofluids has been explained with help of existing phenomena. The increase the ultrasonic velocity in ethylene glycol with TiO2 nanoparticles shows that strong cohesive interaction force rises among the nanoparticles and base fluid. These results divulge that TiO2 nanoparticles can be considered for the applications of next-generation competent heat transfer in nanofluids.

Influencing Factors for Thermal Conductivity Enhancement of Nanofluids

2009 ◽  
Author(s):  
Huaqing Xie ◽  
Wei Yu ◽  
Yang Li ◽  
Lifei Chen
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Influencing Factors ◽  
Silicone Oil ◽  
Thermal Conductivity Enhancement ◽  
Zno Nps ◽  
Conductivity Enhancement ◽  
Heat Transfer Fluids ◽  
Different Shapes ◽  
Al2o3 Nps

Nanofluids have attracted increasing interest for more than a decade. A number of studies have demonstrated that nanofluids presented intriguing heat transfer enhancement performances. We produced a series of nanofluids and measured their thermal conductivities. The most used heat transfer fluids including deionized water (DW), ethylene glycol (EG), glycerol, silicone oil, and the binary mixture of DW and EG were used as the base fluids. Various nanoparticles (NPs) including Al2O3 NPs with different sizes, SiC NPs with different shapes, MgO NPs, ZnO NPs, SiO2 NPs, Fe3O4 NPs, TiO2 NPs, diamond NPs (DNPs), and carbon nanotubes (CNTs) with different pretreatments have been used as additives. In the present paper, we summarized our experimental results to elucidate the influencing factors for thermal conductivity enhancement of nanofluids. The thermal transport mechanisms in nanofluids were further discussed and the promising approaches for optimizing the thermal conductivity of nanofluids were proposed.

scholarly journals Preparation and Enhancement of Thermal Conductivity of Heat Transfer Oil-Based MoS2Nanofluids

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Yuan-Xian Zeng ◽  
Xiu-Wen Zhong ◽  
Zhao-Qing Liu ◽  
Shuang Chen ◽  
Nan Li
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Surface Modification ◽  
Stearic Acid ◽  
Mass Fraction ◽  
Laser Flash ◽  
Thermal Conductivity Enhancement ◽  
Flash Method ◽  
Conductivity Enhancement ◽  
Increasing Temperature

The lipophilic MoS2nanoparticles are synthesized by surface modification with stearic acid (SA). The heat transfer oil-based nanofluids, with the mass fraction of lipophilic nanoparticles varying from 0.25% up to 1.0%, are prepared and their thermal conductivity is determined at temperatures ranging from 40 to 200°C using an apparatus based on the laser flash method. It has been found that the nanofluids have higher thermal conductivity and the thermal conductivity enhancement increased not only with increasing mass fraction of nanoparticles, but also with increasing temperature in the range 40–180°C The results show a 38.7% enhancement of the thermal conductivity of MoS2nanofluid with only 1.0% mass fraction at 180°C.

Nanoparticles Shape Effect on Thermal Conductivity of Nanofluids: A Molecular Dynamics Study

2019 ◽  
Author(s):  
Md. Rakibul Hasan Roni ◽  
AKM M. Morshed ◽  
Amitav Tikadar ◽  
Titan C. Paul ◽  
Jamil A. Khan
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Performance ◽  
Volume Fraction ◽  
Thermal Conductivity Enhancement ◽  
Shape Effect ◽  
Cylindrical Shape ◽  
Transfer Performance ◽  
Conductivity Enhancement ◽  
System Temperature

Abstract Nanofluids have become the subject of theoretical and experimental researches over the few decades due to their enhanced heat transfer performance. In this study, thermal conductivity of copper argon nanofluids is determined through MD simulation. Different types of nanoparticles based on shape was used to make nanofluids. Role of different shape of nanoparticles such as cylindrical, cubical and spherical was disused. Green Kubo method is employed to determine the thermal conductivity of the nanofluids. Result shows that, for volume fraction 3% and 86 K system temperature, thermal conductivity enhancement of nanofluid containing spherical, cubical and cylindrical shape is 15%, 40% and 50% respectively compared with that of base fluid. Thermal conductivity enhancement of nanofluid for spherical particle at 86 K, 94 K and 102 K is 15%, 30% and 40% respectively while for volume fraction 3%, 6% and 9%, the enhancement is 15%, 35% and 45% respectively. The mechanism of increased heat transfer performance for different shape of the nanoparticles is discussed in this paper.

Enhanced Thermal Performance of Ionic Liquid-Al2O3 Nanofluid as Heat Transfer Fluid for Solar Collector

2013 ◽  
Author(s):  
Titan C. Paul ◽  
A. K. M. M. Morshed ◽  
Elise B. Fox ◽  
Ann E. Visser ◽  
Nicholas J. Bridges ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Ionic Liquids ◽  
Thermal Performance ◽  
Thermophysical Properties ◽  
Heat Transfer Fluid ◽  
Al2o3 Nanoparticles ◽  
Diphenyl Oxide ◽  
Volume Percentage

Next generation Concentrating Solar Power (CSP) system requires high operating temperature and high heat storage capacity heat transfer fluid (HTF), which can significantly increase the overall system efficiency for power generation. In the last decade several research going on the efficacy of ionic liquids (ILs) as a HTF in CSP system. ILs possesses superior thermophysical properties compare to currently using HTF such as Therminol VP-1 (mixture of biphenyl and diphenyl oxide) and thermal oil. However, advanced thermophysical properties of ILs can be achieved by dispersing small volume percentage of nanoparticles forming nanofluids, which is called Nanoparticle Enhanced Ionic Liquids (NEILs). In the present study NEILs were prepared by dispersing 0.5% Al2O3 nanoparticles (spherical and whiskers) in N-butyl-N, N, N-trimetylammonium bis(trifluormethylsulfonyl)imide ([N4111][NTf2]) IL. Viscosity, heat capacity and thermal conductivity of NEILs were measured experimentally and compared with the existing theoretical models for liquid–solid suspensions. Additional, the convective heat transfer experiment was performed to investigate thermal performance. The thermal conductivity of NEILs enhanced by ∼5%, heat capacity enhanced by ∼20% compared to the base IL, which also gives 15% enhancement in heat transfer performance.

scholarly journals Thermal Conductivity Enhancement Phenomena in Ionic Liquid-Based Nanofluids (Ionanofluids)

2019 ◽  
Vol 72 (2) ◽  
pp. 21 ◽  
Author(s):  
Kamil Oster ◽  
Christopher Hardacre ◽  
Johan Jacquemin ◽  
Ana P. C. Ribeiro ◽  
Abdulaziz Elsinawi
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Ionic Liquids ◽  
Theoretical Calculations ◽  
Industrial Applications ◽  
Theoretical Modelling ◽  
Conductivity Enhancement ◽  
Heat Transfer Fluids ◽  
Transfer Unit ◽  
Dispersion Of Nanoparticles

The dispersion of nanoparticles into ionic liquids leads to enhancement of their thermal conductivity. Several papers report on various enhancement values, whereas the comparison between these values with those from theoretical calculations is not always performed. These thermal conductivity enhancements are desired due to their beneficial impact on heat transfer performance in processes requiring the utilisation of heat transfer fluids. Moreover, on the one hand, the theoretical modelling of these enhancements might lead to an easier, cheaper, and faster heat transfer unit design, which could be an enormous advantage in the design of novel industrial applications. On the other hand, it significantly impacts the enhancement mechanism. The aim of this work is to discuss the enhancement of thermal conductivity caused by the dispersion of nanoparticles in ionic liquids, including the analysis of their errors, followed by its theoretical modelling. Furthermore, a comparison between the data reported herein with those available in the literature is carried out following the reproducibility of the thermal conductivity statement. The ionic liquids studied were 1-butyl-3-methylimidazolium dicyanamide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium ethylsulfate, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, and 1-hexyl-3-methylimidazolium hexafluorophosphate, while carbon nanotubes, boron nitride, and graphite were selected as nanoparticles to be dispersed in the investigated ionic liquids to design novel heat transfer fluids.

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