A novel method to measure thermal conductivity of nanofluids

Xu, Guoqiang; Fu, Jian; Dong, Bensi; Quan, Yongkai; Song, Guquan

doi:10.1016/j.ijheatmasstransfer.2018.11.014

Cited by 37 publications

(17 citation statements)

References 37 publications

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“…Nanofluidics has shown that at nanoscale, heat diffusion phenomena may greatly differ from their macroscopic counterparts [53,54,55]. Moreover, it has been shown that the thermal conductivity of water at nanoscale is significantly dependent on temperature [56,57,58]. Although more experimental evidence is needed to unveil the rich processes behind the laser-induced deposition of nanostructures, the experimental results presented here show the pertinence of a detailed theoretical study in which the material properties of the solvent in laser-induced deposition experiments are adequately addressed.…”

Section: Discussionmentioning

confidence: 99%

Laser-Induced Deposition of Carbon Nanotubes in Fiber Optic Tips of MMI Devices

Cuando-Espitia

Bernal-Martínez²,

Torres-Cisneros

et al. 2019

Sensors

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The integration of carbon nanotubes (CNTs) into optical fibers allows the application of their unique properties in robust and versatile devices. Here, we present a laser-induced technique to obtain the deposition of CNTs onto the fiber optics tips of multimode interference (MMI) devices. An MMI device is constructed by splicing a section of no-core fiber (NCF) to a single-mode fiber (SMF). The tip of the MMI device is immersed into a liquid solution of CNTs and laser light is launched into the MMI device. CNTs solutions using water and methanol as solvents were tested. In addition, the use of a polymer dispersant polyvinylpyrrolidone (PVP) in the CNTs solutions was also studied. We found that the laser-induced deposition of CNTs performed in water-based solutions generates non-uniform deposits. On the other hand, the laser-induced deposition performed with methanol solutions generates uniform deposits over the fiber tip when no PVP is used and deposition at the center of the fiber when PVP is present in the CNTs solution. The results show the crucial role of the solvent on the spatial features of the laser-induced deposition process. Finally, we register and study the reflection spectra of the as-fabricated CNTs deposited MMI devices.

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Section: Discussionmentioning

confidence: 99%

Laser-Induced Deposition of Carbon Nanotubes in Fiber Optic Tips of MMI Devices

Cuando-Espitia

Bernal-Martínez²,

Torres-Cisneros

et al. 2019

Sensors

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“…The resistance variations measured in the wire can be correlated with the temperature variations and, therefore, the thermal conductivity is calculated. Systematic errors that might affect the measurements, such as errors resulting from natural convection, can be corrected experimentally [5,24].…”

Section: Transient Hot Wire Methodsmentioning

confidence: 99%

“…The current methods developed for thermal conductivity measurements are static methods and can be divided in Steady State Methods and Transient State Methods. The Steady State Methods comprise the parallel plane and coaxial cylinders methods, while the Transient State Methods include the transient hot wire, the transient plane source theory, the temperature oscillation method, the laser flash method and the 3ω method [24]. A brief description of the techniques will be presented in the following subsections.…”

Section: Thermal Conductivity Measurements Overviewmentioning

confidence: 99%

“…Similarly, to obtain the temperature and thus calculate the thermal conductivity, the time variation of the electrical resistance is recorded. Like in the case of the Transient Hot Wire Method, convection currents in the fluid might affect the measurements [5,24].…”

Section: Transient Plane Source Theorymentioning

confidence: 99%

“…The amplitude and phase of the temperature oscillation in the middle of the cylinder are registered. To avoid interferences from the convection phenomena, the amplitude of the applied oscillation should be as small as possible [24,25].…”

Section: Temperature Oscillationmentioning

confidence: 99%

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

et al. 2021

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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.

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Modeling and Performance Optimization of Louvered Fin Radiators in Negative Gauge Pressure Condition

Wan

Liu

et al. 2022

Advcd Theory and Sims

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The purpose of this paper is to study the effect of the structural parameters of louvered fin radiators on its thermal‐hydraulic performance, optimize its structural parameters, and improve the performance of louvered fin radiators in negative gauge pressure condition. The thermal calculation model of louvered fin radiator in negative gauge pressure is established. Then, the effects of design variables on thermal‐hydraulic characteristics are investigated. The second generation of nondominated sorting genetic algorithm (NSGA‐II) is applied to optimize the louvered fin heat exchanger in negative gauge pressure environment. Technique for order preference by similarity to an ideal solution is applied to choose the final optimal solution. Numerical simulation of the solution is conducted and the result is compared with literature in order to verify the optimization method. The optimal structural parameters are obtained under constraints. Compared with the original test piece, the heat transfer rate of optimal solution is increased by 7.7%, and total annual cost is reduced by 24.8%. The present paper establishes optimization method of louvered fin radiators in negative gauge pressure condition, the optimization result is superior to the original radiator. The optimization method can be used in the design of radiators operating in negative gauge pressure conditions.

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A novel method to measure thermal conductivity of nanofluids

Cited by 37 publications

References 37 publications

Laser-Induced Deposition of Carbon Nanotubes in Fiber Optic Tips of MMI Devices

Laser-Induced Deposition of Carbon Nanotubes in Fiber Optic Tips of MMI Devices

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

Modeling and Performance Optimization of Louvered Fin Radiators in Negative Gauge Pressure Condition

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