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 applicability of the modulated temperature differential scanning calorimetry technique to measure specific heat of copper nanofluids by using the ASTM E2719 standard procedure, which is generally applied to thermally stable solids and liquids.
74 citations
TL;DR: In this paper, the combined effects of nonlinear thermal convection and radiation in 3D boundary layer flow of non-Newtonian nanofluid are scrutinized numerically.
Abstract: The combined effects of nonlinear thermal convection and radiation in 3D boundary layer flow of non-Newtonian nanofluid are scrutinized numerically. The flow is induced by the stretching of a flat plate in two lateral directions. The mechanism of heat and mass transport under thermophoretic and Brownian motion is elaborated via implementation of the thermal convective condition. The prevailing two-point nonlinear boundary value problem is reduced to a two-point ordinary differential problem by employing suitable similarity transformations. The solutions are computed by the implementation of homotopic scheme. At the end, a comprehensive parametric study has been conducted to analyze the typical trend of the solutions. It is found that the nanoparticle volume fraction and temperature profiles are stronger for the case of solar radiation in comparison with problem without radiation.
74 citations
TL;DR: In this paper, a thermal non-equilibrium model of the porous medium was used to investigate the thermal convection of a micropolar nanofluid inside a porous enclosure.
Abstract: The present paper deals with numerical investigation of natural convection of a micropolar nanofluid inside a porous enclosure using thermal non-equilibrium model. Rates of the heat transfer and micropolar nanofluid flow are widely considered by presenting contours of nanofluid flow, isotherms of fluid and solid phases, and contours of micro-rotation. Numerical results have been validated with previous references and good concordance has been observed. The results confirm that the thermal non-equilibrium model of the porous medium approaches the thermal equilibrium one by increasing thermal conductivity ratio parameter as well as the heat transfer interface parameter. The strength of convection inside pores of porous medium arises from augmenting H that can result in micro-rotations amplification. The characteristic equations of a micropolar fluid flow are transformed into classic Navier–Stokes equations by increasing porosity and the dimension of pores. Results indicate that the reduction of the thermal resistance of the fluid phase due to an increment of Kr can enhance the heat transfer rate through porous media. Finally, the permeability is important and influences the Nusselt numbers of both the solid matrix and the nanofluid when the nanofluid particles rotate around the center of their gravity.
73 citations
01 Dec 2021
TL;DR: In this paper, a two-dimensional Cattaneo-Christov model was designed by considering the influence of magnetic dipole on a stretching sheet with suspended TC4 (Ti-6Al-4 V) nanoparticles, and the resulting transformed equations were then numerically solved by using shooting technique with Runge-Kutta Fehlberg fourth-fifth order method.
Abstract: Sequel to the fact that nanofluids exhibit greater thermal resistance and noting the applications of non-Newtonian (Maxwell) liquid flow on a stretching sheet with suspended nanoparticles TC4 (Ti-6Al-4 V), the current mathematical model is designed by considering the influence of magnetic dipole. The heat transfer in a two-dimensional flow of Maxwell nanoliquid over a stretching sheet is carried out by means of Cattaneo–Christov model. The base liquid (Engine oil) with suspended TC4 (Ti-6Al-4 V) nanoparticles are considered in the study. By using suitable similarity transformations, the flow and energy equations of the flow model are converted into ordinary differential equations (ODEs). Further, the resulting transformed equations are then numerically solved by using shooting technique with Runge–Kutta Fehlberg fourth–fifth order method (RKF-45). The significant findings of the current model are that the Newtonian liquid shows better thermal performance for rise in values of volume fraction and ferromagnetic interaction parameter as compared to Maxwell fluid. The upsurge in values of volume fraction and thermal relaxation parameter improves the rate of heat transfer and skin friction coefficient.
73 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