Experimental and numerical investigation of nanofluids heat transfer characteristics for application in solar heat exchangers

Ebrahimnia-Bajestan, Ehsan; Moghadam, Mohammad Charjouei; Niazmand, Hamid; Daungthongsuk, Weerapun; Wongwises, Somchai

doi:10.1016/j.ijheatmasstransfer.2015.08.107

Cited by 213 publications

(65 citation statements)

References 56 publications

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“…Reddy and Rao [71], Arulprakasajothi et al [74] and Abdolbaq et al [75] found that for TiO 2 nanofluids in intensely low concentrations, the Nu enhancements were higher than friction factor. In particular, Water (a) Nanoparticles in smaller diameters could bring out greater Brownian motion and result in higher average shear stress ratio and heat transfer effect (b) Size of particle plays greater roles in the enhancement of convection heat transfer than that in thermal conductivity (c) Particle migrations on the boundary layer can improve h of TiO 2 nanofluids Saha and Paul [90] Numerical Tube Turbulent Water (a) h was positively related to particle loading and Re, but negatively correlated to nanoparticle size (b) h was more affected by the particle size and Brownian motion than thermal conductivity of nanofluid Celata et al [91] Experimental and numerical Two-loop test rig Laminar to transitional Water (a) h was interactional with the parameters including k, q, l, cp, particle size, shape, loading and surfactants (b) h was affected by the initial values of particle size and the size of agglomeration occurring in the nanofluids He et al [20] Experimental Vertical tube Laminar to turbulent Water (a) The maximum enhancement of h was 12% for 1.18 vol.% particle loading in laminar flow regime (b) h increased with an increase in particle loading in both of laminar and turbulent flow regimes (c) Particle loading had greater role in turbulent flow regime (d) Particle size did not show great role in h Chen et al [92] Experimental Vertical tube Turbulent Water (a) The enhancements of the h at 0.5, 1.0 and 2.5 wt.% loading at x/D = 50.4 were respectively 11.8%, 23.5% and 24.9% (b) Enhancement of h by nanofluids was much higher than that of thermal conductivity (c) The tubular nanoparticles with large aspect ratios provided a higher enhancement of h than spherical particles Ebrahimnia-Bajestan et al [93] Experimental and numerical…”

Section: Influence Of Particle Loading and Rementioning

confidence: 98%

A comprehensive review on heat transfer characteristics of TiO2 nanofluids

Yang

2017

International Journal of Heat and Mass Transfer

121

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Section: Influence Of Particle Loading and Rementioning

confidence: 98%

A comprehensive review on heat transfer characteristics of TiO2 nanofluids

Yang

2017

International Journal of Heat and Mass Transfer

121

View full text Add to dashboard Cite

“…In order to perform the CFD analysis first, Author has developed the solid model of the solar heat exchanger on the basis of geometry considered during the experimental analysis performed by Bajestan et.al [1].…”

Section: Development Cfd Model Of Heat Exchangermentioning

confidence: 99%

Numerical Analysis of Solar Heat Exchanger with Different Types of Ribs to Enhance Heat Transfer

Gupta¹

2018

IJRASET

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The solar heat exchanger is used for transferring solar energy to another medium. To increase the heat transfer rate many researchers optimized the different process parameters of the solar heat exchanger. Here in this work, it performs the numerical analysis of solar heat exchanger. To calculated the effect of different Reynolds number on heat transfer here it considered four different Reynolds number that is 500, 900, 1300 and 1700. Here in this work, considered solar heat exchanger with different shapes of ribs inside the heat exchanger, for calculating the effect of the shape of ribs, it considered three different types of rib that are circular, square and triangular shape rib and calculate the value of heat transfer coefficient at different Reynolds number. After analyzing rib type solar heat exchanger for simple water flow, it is then considered for nanofluid flow. For calculating the effect of ribs on nanofluid flow here it considered Titanium-oxide nanofluid for all different types of ribs and calculate the value of heat transfer coefficient. Keywords: Solar heat exchanger, nanofluid, ribs, single phase model, multiphase model I.INTRODUCTION Nanotechnology is a branch of science and technology which makes use of the particles in the nanoscale order, namely in the molecular and atomic order respectively. In this field, the particles considered are analyzed individually from their bulk specifications. The properties of the bulk materials, on the whole, are expected to remain unchanged, whereas at the nanoscale order these properties alter. When these solid particles of nanoscale order are dispersed in any fluid medium known as the base fluids collectively they are stated as nanofluids. In this study, the behavior of these nanofluids is analyzed when they are used in the solar heat exchangers. Many researchers discuss the synthesis of nanofluids, but first, it is necessary to understand what heat exchangers are and what its various types. A heat exchanger is a device that exchanges the heat between two or more flowing fluids. In simple words, one flowing fluid is at the lower temperature, called the cold fluid, and the other fluid is at the higher temperature, called the hot fluid, from which heat has to be extracted.

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“…For example, the thermal conductivity of copper at room temperature is about 700 times greater than that of water, and about 3000 times greater than that of engine oil [8,9]. As a result, nanofluids, which are dilute suspensions of nano-size particles, have drawn much attention [10][11][12][13]. For instance, heat transfer of natural convection could be enhanced with a small volume fraction of nanoparticles [14].…”

Section: Introductionmentioning

confidence: 99%

Effect of Thermal-Electric Cross Coupling on Heat Transport in Nanofluids

Kang

Wang

2017

Energies

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Nanofluids have an enhanced thermal conductivity compared with their base fluid. Although many mechanisms have been proposed, few of them could give a satisfactory explanation of experimental data. In this study, a mechanism of heat transport enhancement is proposed based on the cross coupling of thermal and electric transports in nanofluids. Nanoparticles are viewed as large molecules which have thermal motion together with the molecules of the base fluid. As the nanoparticles have surface charges, the motion of nanoparticles in the high-temperature region will generate a relatively strong varying electric field through which the motion will be transported to other nanoparticles, leading to a simultaneous temperature rise of low-temperature nanoparticles. The local base fluid will thus be heated up by these nanoparticles through molecular collision. Every nanoparticle could, therefore, be considered as an internal heat source, thereby enhancing the equivalent thermal conductivity significantly. This mechanism qualitatively agrees with many experimental data and is thus of significance in designing and applying nanofluids.

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Experimental and numerical investigation of nanofluids heat transfer characteristics for application in solar heat exchangers

Cited by 213 publications

References 56 publications

A comprehensive review on heat transfer characteristics of TiO2 nanofluids

A comprehensive review on heat transfer characteristics of TiO2 nanofluids

Numerical Analysis of Solar Heat Exchanger with Different Types of Ribs to Enhance Heat Transfer

Effect of Thermal-Electric Cross Coupling on Heat Transport in Nanofluids

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