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 paper, the authors analyzed the Darcy-Forchheimer flow of viscous nanofluid by curved stretchable surface and solved the resulting nonlinear system through shooting technique.
Abstract: Purpose
The purpose of present communication is to analyze Darcy–Forchheimer flow of viscous nanofluid by curved stretchable surface. Flow in porous medium is characterized by Darcy–Forchheimer relation. Brownian diffusion and thermophoresis are considered. Convective heat and mass boundary conditions are also used at the curved stretchable surface.
Design/methodology/approach
The resulting nonlinear system is solved through shooting technique.
Findings
Skin friction coefficient is enhanced for larger porosity parameter and inertia coefficient while reverse trend is noticed for curvature parameter. Local Nusselt number is enhanced for higher Prandtl number and thermal Biot number, whereas the opposite trend is seen via curvature parameter, porosity parameter, inertia coefficient, thermophoresis parameter and Brownian motion parameter. Local Sherwood number is enhanced for Schmidt number, Brownian motion parameter and concentration Biot number, while reverse trend is noticed for curvature parameter, porosity parameter, inertia coefficient and thermophoresis parameter.
Originality/value
To the best of author’s knowledge, no such consideration has been given in the literature yet.
81 citations
TL;DR: In this article, the authors present the significant effects of suction and magnetic field over a moving plate containing hybrid nanofluid with base fluid is water, Alumina Oxide (Al2O3) and copper (Cu) as the nanoparticles.
Abstract: In this new era of technology in fluid field, hybrid nanofluid has become a fruitful interest topic among researchers due to it thermal properties and potential which gives better result compared to nanofluid in enhancing the heat transfer rate. The intention here is to present the significant effects of suction and magnetic field over a moving plate containing hybrid nanofluid with base fluid is water, Alumina Oxide (Al2O3) and Copper (Cu) as the nanoparticles. A mathematical modelling consists of partial differential equation for the fluid flow are constructed and transformed to a set of ordinary differential equations hence solved numerically using bvp4c in MATLAB. Effects of magnetohydrodynamics (MHD), M, suction, S and relevant thermophysical properties on velocity, temperature, skin friction, C f and local Nusselt, N u x number are thoroughly examined and presented graphically. It is noted that duality exists in certain range when λ c - 1 and unique solution at λ > - 1 . The range on duality of solution are widen as the values of M and S increase. Due to that, a stability analysis is implied to determine which duality of solution is stable and realizable. As M and ϕ 2 increase, the skin friction increases. For rate of heat transfer, as M increase, the heat transfer rate increase while for arising of ϕ 2 , the heat transfer decrease. Furthermore, it is noted that the hybrid nanofluid possess better result compared to nanofluid.
81 citations
TL;DR: A comparison of thermal characteristics of Al 2 O 3 /water and CuO/water nanofluids in transition flow through a straight circular duct fitted with helical screw tape inserts was made in this paper.
80 citations
TL;DR: In this paper, a horn ultrasonic dismembrator was used for different periods from 0h to 5h for nanofluid preparation, and the effect of ultrasonication duration on colloidal dispersion and thermophysical properties was analyzed.
80 citations
TL;DR: In this paper, the mixed convective peristaltic transport of copper-water nanofluid under the influence of constant applied magnetic field was examined in an asymmetric channel.
Abstract: Recent development in biomedical engineering has enabled the use of the magnetic nanoparticles in modern drug delivery systems with great utility Nanofluids composed of magnetic nanoparticles have the characteristics to be manipulated by external magnetic field and are used to guide the particles up the bloodstream to a tumor with magnets In this study we examine the mixed convective peristaltic transport of copper–water nanofluid under the influence of constant applied magnetic field Nanofluid is considered in an asymmetric channel Aside from the effect of applied magnetic field on the mechanics of nanofluid, its side effects ie the Ohmic heating and Hall effects are also taken into consideration Heat transfer analysis is performed in presence of viscous dissipation and heat generation/absorption Mathematical modeling is carried out using the lubrication analysis Resulting system of equations is numerically solved Impact of embedded parameters on the velocity, pressure gradient, streamlines and temperature of nanofluid is examined Effects of applied magnetic field in presence and absence of Hall effects are studied and compared Results depict that addition of copper nanoparticles reduces the velocity and temperature of fluid Heat transfer rate at the boundary enhances by increasing the nanoparticles volume fraction Increase in the strength of applied magnetic field tends to decrease/increase the velocity/temperature of nanofluid Further presence of Hall effects reduces the variations brought in the state of fluid when strength of applied magnetic field is increased
80 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