Thermal Conductivity of Ionic Liquids at Atmospheric Pressure: Database, Analysis, and Prediction Using a Topological Index Method

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.

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Tunning CO2 Separation Performance of Ionic Liquids through Asymmetric Anions

Molecules ◽

10.3390/molecules27020413 ◽

2022 ◽

Vol 27 (2) ◽

pp. 413

Author(s):

Bruna F. Soares ◽

Daniil R. Nosov ◽

José M. Pires ◽

Andrey A. Tyutyunov ◽

Elena I. Lozinskaya ◽

...

Keyword(s):

Ionic Liquids ◽

Atmospheric Pressure ◽

Time Lag ◽

Gas Permeation ◽

Separation Performance ◽

Experimental Conditions ◽

Feed Pressure ◽

Similar Chemical ◽

Supported Ionic Liquid Membranes ◽

Gas Separation Performance

This work aims to explore the gas permeation performance of two newly-designed ionic liquids, [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2], in supported ionic liquid membranes (SILM) configuration, as another effort to provide an overall insight on the gas permeation performance of functionalized-ionic liquids with the [C2mim]+ cation. [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2] single gas separation performance towards CO2, N2, and CH4 at T = 293 K and T = 308 K were measured using the time-lag method. Assessing the CO2 permeation results, [C2mim][CF3BF3] showed an undermined value of 710 Barrer at 293.15 K and 1 bar of feed pressure when compared to [C2mim][BF4], whereas for the [C2mim][CF3SO2C(CN)2] IL an unexpected CO2 permeability of 1095 Barrer was attained at the same experimental conditions, overcoming the results for the remaining ILs used for comparison. The prepared membranes exhibited diverse permselectivities, varying from 16.9 to 22.2 for CO2/CH4 and 37.0 to 44.4 for CO2/N2 gas pairs. The thermophysical properties of the [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2] ILs were also determined in the range of T = 293.15 K up to T = 353.15 K at atmospheric pressure and compared with those for other ILs with the same cation and anion’s with similar chemical moieties.

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405 Measurement of Thermal Conductivity of Thermal Insulations under Atmospheric Pressure and Vacuum Conditions

The Proceedings of Yamanashi District Conference ◽

10.1299/jsmeyamanashi.2004.99 ◽

2004 ◽

Vol 2004 (0) ◽

pp. 99-100

Author(s):

Takahiro OHMURA ◽

Mikinori TSUBOI ◽

Toshio TOMIMURA

Keyword(s):

Thermal Conductivity ◽

Atmospheric Pressure ◽

Thermal Insulations

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

ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer ◽

10.1115/mnhmt2012-75118 ◽

2012 ◽

Cited By ~ 1

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.

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A New Method to Measure Prandtl Number and Thermal Conductivity of Fluids

Journal of Applied Mechanics ◽

10.1115/1.4011438 ◽

1957 ◽

Vol 24 (1) ◽

pp. 25-28

Author(s):

E. R. G. Eckert ◽

T. F. Irvine

Keyword(s):

Thermal Conductivity ◽

Boundary Layer ◽

Prandtl Number ◽

High Velocity ◽

Atmospheric Pressure ◽

New Method ◽

Test Results ◽

Test Setup ◽

Velocity Boundary Layer ◽

Layer Flow

Abstract A new method is described by which the Prandtl number and indirectly the thermal conductivity of fluids can be measured. The method is based on the fact that a well-established, unique relation exists between the Prandtl number and the recovery factor for laminar high-velocity boundary-layer flow. The test setup is described which has been devised for such measurements, and test results are presented for air at atmospheric pressure and temperatures between 60 and 350 F.

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