The field of nanofluids has received interesting attention since the concept of dispersing nanoscaled particles into a fluid was first introduced in the later part of the twentieth century This is evident from the increased number of studies related to nanofluids published annually The increasing attention on nanofluids is primarily due to their enhanced thermophysical properties and their ability to be incorporated into a wide range of thermal applications ranging from enhancing the effectiveness of heat exchangers used in industries to solar energy harvesting for renewable energy production Owing to the increasing number of studies relating to nanofluids, there is a need for a holistic review of the progress and steps taken in 2019 concerning their application in heat transfer devices This review takes a retrospective look at the year 2019 by reviewing the progress made in the area of nanofluids preparation and the applications of nanofluids in various heat transfer devices such as solar collectors, heat exchangers, refrigeration systems, radiators, thermal storage systems and electronic cooling This review aims to update readers on recent progress while also highlighting the challenges and future of nanofluids as the next-generation heat transfer fluids Finally, a conclusion on the merits and demerits of nanofluids is presented along with recommendations for future studies that would mobilise the rapid commercialisation of nanofluids

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An updated review of nanofluids in various heat transfer devices

Performance and emissions of a diesel engine using sunflower biodiesel with a renewable antioxidant additive from bio-oil

The synthesis method of in-situ/chemical co-precipitation was implemented for the addition of Fe3O4 nanoparticles on the surface of nanodiamond (ND) nanoparticles, and it is characterized by using x-ray diffraction, transmission electron microscopy and the magnetic property was estimated from the vibrating sample magnetometer. The 60:40% water-ethylene glycol mixture is used as a base fluid for the preparation of ND-Fe3O4 hybrid nanofluids. Experimental techniques are used to measure the thermophysical properties at various particle volume loadings, and temperatures and the obtained data is validated with literature data. The heat transfer, friction factor, and pumping power are evaluated at particle volume loadings from 0.05% to 0.2% and in the Reynolds number range from 2105 to 8126. The concepts of the second law of thermodynamics are used to evaluate the thermal entropy generation, frictional entropy generation and exergy efficiency of the hybrid nanofluids. The thermal conductivity enhancements are 5.03% and 12.79%, whereas, the viscosity enhancements are 108% and 50.84% at particle loading of 0.2% at temperatures of 20 °C and 60 °C in comparison with base fluid. The Nusselt number is augmented to 15.65%; thermal entropy generation is reduced to 20%, frictional entropy generation is augmented to 272.48% and exergy efficiency is increased to 38.24% with a maximum penalty in friction factor of 1.128-times at 0.2% particle loading and a Reynolds number of 7502 against base fluid data. New equations are modelled to evaluate the thermophysical properties, Nusselt number, and friction factor.

Experimental investigation of thermo-physical properties, heat transfer, pumping power, entropy generation, and exergy efficiency of nanodiamond + Fe3O4/60:40% water-ethylene glycol hybrid nanofluid flow in a tube

Innovative heat elimination technologies from the radiator are needed for weight reduction in an automotive vehicle to increase the overall performance. The fluids used nowadays are based on a combination of distilled water (DW) and ethylene glycol (EG), and also using nanofluids for improving heat transfer performance has been increased within the last couple of years. The use of aluminum oxide (Al2O3) doped with unmilled silicon carbide (SiCUM) nanoparticles and milled Silicon carbide (SiCM) nanoparticles dispersed in DW and EG at 50:50 volumetric proportions experimented in this work. The focus for the important characterization of the nf which includes thermophysical properties is elaborated in this paper. The outcomes showed an optimum improvement regarding the overall thermal performance of 28.34 % making use of Al2O3 doped with milled Silicon carbide(SiCM) at a volume concentration of 0.8 %. This might be due to the size reduction of SiC nanoparticles by the milling process involved in this experiment.

Assessment of heat transfer characteristics and system physiognomies using hybrid nanofluids in an automotive radiator

Entropy generation and exergy efficiency analysis of ethylene glycol-water based nanodiamond + Fe3O4 hybrid nanofluids in a circular tube

Consequence of nanoparticles size on heat transfer characteristics of a radiator

In this present study, biodiesel is a cleaner burning alternative fuel to the Neat diesel fuel. However, several studies are pointed out that increase in NOx emission for biodiesel when compared with the Neat diesel fuel. The aim of the present study is to analyze the effect of antioxidant (p-phenylenediamine) on engine emissions of a Diesel engine fuelled with methyl ester of annona oil. The antioxidant is mixed in various concentrations (0.010 to 0.040% (w/w)) with methyl ester of annona oil. Result shows that antioxidant additive mixture (MEAO + P200) is effective in control of NOx and HC emission of methyl ester of annona oil fuelled engine without doing any engine modification.

Effects of antioxidant additives on exhaust emissions reduction in compression ignition engine fueled with methyl ester of annona oil

In this paper, the heat transfer coefficient and the heat transfer rate of a heat exchanger is evaluated by using nanofluids. The silicon carbide nanoparticles, milled and sonificated as nanofluids...

Consequence of nanoparticle physiognomies on heat transfer characteristics of heat exchanger

In heat transfer applications, nanofluids are utilized to increase thermal
 conductivity and heat transfer coefficient. The difficulty of nanoparticle
 stabilization in the fluids is a significant problem in heat transfer
 applications. Heat exchanger materials may wear and erode as a result of the
 additional nanoparticle. When compared to mono nanofluids, this can be
 lowered by using hybrid nanofluids. In this work, hybrid nanofluids are used
 in a radiator under laminar flow at 75?C, and the effect of volume
 concentration on heat transfer enhancement is investigated. The
 thermophysical characteristics of hybrid nanofluids are investigated using
 SiC and Al2O3 at 0.1v % and 0.2v %. The results revealed that a hybrid
 nanofluid with a higher volume concentration improves heat transfer.
 Finally, regression analysis for laminar flow is carried out and
 correlations for experimental Nusselt number and friction factor values were
 developed. The impact of particle size, flow rate, and temperature on the
 radiator?s heat transfer enhancement is investigated using hybrid nanofluid
 at 75?C. It is observed that the size of the nanoparticle has a substantial
 effect on heat transfer characteristics. It is concluded that using
 smaller-sized hybrid nanoparticles of Al2O3/SiC-S with less volume
 concentration enhances heat transfer and reduces radiator size compared to
 conventional coolants.

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Ratchagaraja Dhairiyasamy

Papers

Assessment of heat transfer characteristics and system physiognomies using hybrid nanofluids in an automotive radiator

Consequence of nanoparticles size on heat transfer characteristics of a radiator

Effects of antioxidant additives on exhaust emissions reduction in compression ignition engine fueled with methyl ester of annona oil

Consequence of nanoparticle physiognomies on heat transfer characteristics of heat exchanger

Experimental investigation of thermophysical properties and heat transfer characteristics of hybrid nanofluids based on particle size