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: A review of the state-of-the-art nanofluid studies on such topics as thermo-physical properties, convective heat transfer performance, boiling heat transfer, and critical heat flux (CHF) enhancement can be found in this article.
183 citations
TL;DR: In this paper, the effect of nano particles on the bubble type absorption by experiment and to find the optimal conditions to design highly effective compact absorber for NH3/H2O absorption system is examined.
Abstract: The objectives of this paper are to examine the effect of nano particles on the bubble type absorption by experiment and to find the optimal conditions to design highly effective compact absorber for NH3/H2O absorption system. The initial concentrations of NH3/H2O solution and the kinds and the concentrations of nano particles are considered as key parameters. The results show that the addition of nano particles enhances the absorption performance up to 3.21 times. Moreover, the absorption rate increases with increasing concentration of nano particles and the nano particles are more effective for lower absorption potential solution. The potential enhancement mechanism for binary nanofluid is suggested. The experimental correlations of the effective absorption ratio for each nano particles, Cu, CuO, and Al2O3, are suggested within ±10% error-band.
182 citations
TL;DR: In this article, a dispersion model is used to account for the presence of nanoparticles in a Laminar-flow convective heat transfer of nanofluid in a circular tube with constant wall temperature boundary condition.
Abstract: Laminar-flow convective heat transfer of nanofluid in a circular tube with constant wall temperature boundary condition is investigated numerically. A dispersion model is used to account for the presence of nanoparticles. Numerical predictions are in agreement with experimental results obtained in our laboratory for different particles in different sizes. Results clearly show that addition of nanoparticles to base liquid produces considerable enhancement of heat transfer. Heat transfer coefficients increase with nanoparticle concentration. Decreasing nanoparticles size at a specific concentration increases heat transfer coefficients.
182 citations
Cites background from "Investigation on Convective Heat Tr..."
...Experimental measurements indicated that heat transfer enhancement in nanofluids compared to base fluids is greater than what the homogeneous model predicts [25]....
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...Also, Xuan and Li investigated heat transfer of Cu=water nanofluid under constant wall heat flux in turbulent flow regime and concluded that convective heat transfer enhancement of nanofluid may be related to thermal conductivity increase or random movement and dispersion of nanoparticles in nanofluid [25]....
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...6-fold the heat transfer for the base fluid [25]....
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TL;DR: In this article, the authors investigated the convective heat and mass transfer in nanofluid flow over a stretching sheet subject to hydromagnetic, viscous dissipation, chemical reaction and Soret effects.
182 citations
TL;DR: A review of the heat transfer applications of nanofluids to develop directions for future work is presented in this article, where most of the results are in agreement with the results of experimental work.
Abstract: The low thermal properties of liquids have led to investigations into additives of small size (less than 100 nm solid particles) to enhance their heat transfer properties and hydrodynamic flow. To summarise the experimental and numerical studies, this paper reviews these computational simulations and finds that most of them are in agreement with the results of experimental work. Many of the studies report enhancements in the heat transfer coefficient with an increase in the concentration of solid particles. Certain studies with a smaller particle size indicated an increase in the heat transfer enhancement when compared to values obtained with a larger size. Additionally, the effect of the shape of the flow area on the heat transfer enhancement has been explored by a number of studies. All of the studies showed a nominal increase in pressure drop. The significant applications in the engineering field explain why so many investigators have studied heat transfer with augmentation by a nanofluid in the heat exchanger. This article presents a review of the heat transfer applications of nanofluids to develop directions for future work. The high volume fraction of various nanofluids will be useful in car radiators to enhance the heat transfer numerically and experimentally. Correlation equations can expose relationships between the Nusselt number, the Reynolds number, the concentration and the diameter of the nanoparticles. On the other hand, more work is needed to compare the shapes (e.g., circular, elliptical and flat tube) that might enhance the heat transfer with a minimal pressure drop.
182 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