Investigation on Convective Heat Transfer and Flow Features of Nanofluids
01 Feb 2003-Journal of Heat Transfer-transactions of The Asme (American Society of Mechanical Engineers)-Vol. 125, Iss: 1, pp 151-155
TL;DR: In this article, an innovative new class of heat transfer fluids can be engineered by suspending metallic nanoparticles in conventional heat-transfer fluids, which are expected to exhibit high thermal conductivities compared to those of currently used heat transfer fluid, and they represent the best hope for enhancing heat transfer.
Abstract: Low thermal conductivity is a primary limitation in the development of energy-efficient heat transfer fluids that are required in many industrial applications. In this paper we propose that an innovative new class of heat transfer fluids can be engineered by suspending metallic nanoparticles in conventional heat transfer fluids. The resulting {open_quotes}nanofluids{close_quotes} are expected to exhibit high thermal conductivities compared to those of currently used heat transfer fluids, and they represent the best hope for enhancement of heat transfer. The results of a theoretical study of the thermal conductivity of nanofluids with copper nanophase materials are presented, the potential benefits of the fluids are estimated, and it is shown that one of the benefits of nanofluids will be dramatic reductions in heat exchanger pumping power.
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TL;DR: In this article, an overview of the important physical phenomena necessary for the determination of effective thermal conductivity of nanofluid is provided, and the increase in the specific area as well as Brownian motion are supposed to be the most significant reasons for the anomalous enhancement in thermal conductivities.
Abstract: This paper provides an overview of the important physical phenomena necessary for the determination of effective thermal conductivity of nanofluid. Increase in the specific area as well as Brownian motion are supposed to be the most significant reasons for the anomalous enhancement in thermal conductivity of nanofluid. Usual heat transfer fluids with suspended ultra fine particles of nanometre size are named as nanofluids, which have opened a new dimension in heat transfer processes. This work presents the increase of thermal conductivity with temperatures for nanofluids with water as base fluid and particles of Al2O3 or CuO as suspension material. Transient hot-wire method is used for the measurement of thermal conductivity. Heat retaining time is introduced and estimated experimentally. The heat retaining time of 0.8% volume fraction of Al22O3 nanofluid increases up to 47.05% of the base fluid and 0.8% volume fraction of CuO nanofluid increases up to 61.7% of the base fluid. The results indicate an increase of enhancement of thermal conductivity with temperature found to be agreeing excellently with a wide range of different models as well as the data published in literature.
69 citations
TL;DR: In this paper, the authors used an apparatus based on the laser flash method to determine the thermal conductivity of MoS2 nanofluid at temperatures ranging from 40 to 200°C.
Abstract: The lipophilic MoS2 nanoparticles are synthesized by surface modification with stearic acid (SA). The heat transfer oil-based nanofluids, with the mass fraction of lipophilic nanoparticles varying from 0.25% up to 1.0%, are prepared and their thermal conductivity is determined at temperatures ranging from 40 to 200°C using an apparatus based on the laser flash method. It has been found that the nanofluids have higher thermal conductivity and the thermal conductivity enhancement increased not only with increasing mass fraction of nanoparticles, but also with increasing temperature in the range 40-180°C The results show a 38.7% enhancement of the thermal conductivity of MoS2 nanofluid with only 1.0% mass fraction at 180°C.
69 citations
TL;DR: In this paper, the authors investigated the buoyancy driven mixed convective flow and heat transfer characteristics of water-based nanofluid past a circular cylinder in cross flow using a SUPG based finite element method.
69 citations
TL;DR: In this article, the photonic nanofluids composed of magnetic-plasmonic Fe3O4/TiN nanoparticles were designed and prepared to realize the full-spectrum absorption of incident solar energy.
69 citations
TL;DR: In this paper, the authors numerically examined heat transfer and flow in circular tubes fitted with dimpled twisted tape inserts, and Al 2 O 3 -water nanofluid is employed.
69 citations
References
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Book•
01 Jan 1985
TL;DR: In this article, the physical concepts and methodologies of heat and mass transfer are explained for advanced undergraduate engineering majors, using a systematic method for problem solving and discusses the relationship of heat transfer to many important practical applications through examples and problems.
Abstract: This book, designed for advanced undergraduate engineering majors, explains the physical concepts and methodologies of heat and mass transfer. It uses a systematic method for problem solving and discusses the relationship of heat and mass transfer to many important practical applications through examples and problems. A and significant contribution is the extensive use of the First Law of thermodynamics.
4,113 citations
TL;DR: In this article, the authors used a Brookfield rotating viscometer to measure the viscosities of the dispersed fluids with γ-alumina (Al2O3) and titanium dioxide (TiO2) particles at a 10% volume concentration.
Abstract: Turbulent friction and heat transfer behaviors of dispersed fluids (i.e., uttrafine metallic oxide particles suspended in water) in a circular pipe were investigated experimentally. Viscosity measurements were also conducted using a Brookfield rotating viscometer. Two different metallic oxide particles, γ-alumina (Al2O3) and titanium dioxide (TiO2), with mean diameters of 13 and 27 nm, respectively, were used as suspended particles. The Reynolds and Prandtl numbers varied in the ranges l04-I05 and 6.5-12.3, respectively. The viscosities of the dispersed fluids with γ-Al2O3 and TiO2 particles at a 10% volume concentration were approximately 200 and 3 times greater than that of water, respectively. These viscosity results were significantly larger than the predictions from the classical theory of suspension rheology. Darcy friction factors for the dispersed fluids of the volume concentration ranging from 1% to 3% coincided well with Kays' correlation for turbulent flow of a single-phase fluid. The Nusselt n...
3,730 citations
3,019 citations
"Investigation on Convective Heat Tr..." refers background in this paper
...Hamilton and Crasser (1962) have developed a more elaborate model for the effective thermal conductivity of twocomponent mixtures as a function of the conductivity of the pure materials, the composition of the mixture, and the shape of the dispersed particles....
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TL;DR: In this paper, a transient hot-wire method was used to measure the thermal conductivity of a small amount of nanoparticles and the experimental results showed that these nanoparticles have substantially higher thermal conductivities than the same liquids without nanoparticles.
Abstract: Oxide nanofluids were produced and their thermal conductivities were measured by a transient hot-wire method. The experimental results show that these nanofluids, containing a small amount of nanoparticles, have substantially higher thermal conductivities than the same liquids without nanoparticles. Comparisons between experiments and the Hamilton and Crosser model show that the model can predict the thermal conductivity of nanofluids containing large agglomerated Al{sub 2}O{sub 3} particles. However, the model appears to be inadequate for nanofluids containing CuO particles. This suggests that not only particle shape but size is considered to be dominant in enhancing the thermal conductivity of nanofluids.
2,811 citations
TL;DR: In this article, the authors proposed two different approaches for deriving heat transfer correlation of the nanofluid, and investigated the mechanism of heat transfer enhancement of the nano-fluid.
2,355 citations