Nanofluids are potential heat transfer fluids with enhanced thermophysical properties and heat transfer performance can be applied in many devices for better performances (i.e. energy, heat transfer and other performances). In this paper, a comprehensive literature on the applications and challenges of nanofluids have been compiled and reviewed. Latest up to date literatures on the applications and challenges in terms of PhD and Master thesis, journal articles, conference proceedings, reports and web materials have been reviewed and reported. Recent researches have indicated that substitution of conventional coolants by nanofluids appears promising. Specific application of nanofluids in engine cooling, solar water heating, cooling of electronics, cooling of transformer oil, improving diesel generator efficiency, cooling of heat exchanging devices, improving heat transfer efficiency of chillers, domestic refrigerator-freezers, cooling in machining, in nuclear reactor and defense and space have been reviewed and presented. Authors also critically analyzed some of the applications and identified research gaps for further research. Moreover, challenges and future directions of applications of nanofluids have been reviewed and presented in this paper. Based on results available in the literatures, it has been found nanofluids have a much higher and strongly temperature-dependent thermal conductivity at very low particle concentrations than conventional fluids. This can be considered as one of the key parameters for enhanced performances for many of the applications of nanofluids. Because of its superior thermal performances, latest up to date literatures on this property have been summarized and presented in this paper as well. However, few barriers and challenges that have been identified in this review must be addressed carefully before it can be fully implemented in the industrial applications.

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A review on applications and challenges of nanofluids

A review of the applications of nanofluids in solar energy

A review of nanofluid stability properties and characterization in stationary conditions

Rheological behaviour of ethylene glycol based titania nanofluids

The purpose of this review summarizes the important published articles on the enhancement of the convection heat transfer in heat exchangers using nanofluids on two topics. The first section focuses on presenting the theoretical and experimental results for the effective thermal conductivity, viscosity and the Nusselt number reported by several authors. The second section concentrates on application of nanofluids in various types of heat exchangers: plate heat exchangers, shell and tube heat exchangers, compact heat exchangers and double pipe heat exchangers.

Application of nanofluids in heat exchangers: A review

https://philon.cheng.auth.gr/philon/site/sdocs/s36.pdf

Counter-current gas-liquid flow in a vertical narrow channel—Liquid film characteristics and flooding phenomena

New data are presented on drop size distribution at high dispersed phase fractions of organic-in-water mixtures, obtained with a light back scattering technique (3 Dimensional Optical Reflectance Measurement technique, 3D ORM). The 3D ORM technique, which provides fast, in-situ and on-line drop distribution measurements even at high concentrations of the dispersed phase, is validated using an endoscope attached to a high-speed video recorder. The two techniques compared favourably when used in a dispersion of oil (density (p) = 828 kg m(-3), viscosity (mu) = 5.5 mPa s, interfacial tension (sigma(i)) = 44.7 mNm(-1)) in water for a range of 5-10% dispersed phase fractions. Data obtained with the ORM instrument for dispersed phase fractions up to 60% and impeller speeds 3 50 - 5 50 rpm showed a decrease in the maximum and the Sauter mean drop diameters with increasing impeller speed. Phase fractions did not seem to significantly affect drop size. Both techniques showed that drop size distributions could be fitted by the log-normal distribution. (c) 2005 Society of Chemical Industry

Drop size distribution in highly concentrated liquid–liquid dispersions using a light back scattering method

Liquid layer characteristics in stratified—Atomization flow

Characteristics of developing free falling films at intermediate Reynolds and high Kapitza numbers

A photometric technique for film thickness measurements is described in this paper It is based on the absorption of light passing through a layer of dyed liquid and takes advantage of small sized diode laser sources and sensitive light sensors The method is non-intrusive, easy to use and to calibrate and can be implemented at relatively low cost Laboratory tests of the technique have yielded satisfactory accuracy and repeatability Moreover, the technique allows measurements with a good spatial resolution Flowing film thickness measurements made photometrically are compared directly to measurements taken simultaneously with a “parallel wire conductance probe” Time-averaged film heights, RMS values and other statistical information have been obtained by analyzing these instantaneous film thickness records With regard to the time-averaged values of liquid film thickness, there is a satisfactory agreement between the two measuring techniques

Spiros V. Paras

Papers

Counter-current gas-liquid flow in a vertical narrow channel—Liquid film characteristics and flooding phenomena

Drop size distribution in highly concentrated liquid–liquid dispersions using a light back scattering method

Liquid layer characteristics in stratified—Atomization flow

Characteristics of developing free falling films at intermediate Reynolds and high Kapitza numbers

Measurement of liquid film thickness using a laser light absorption method