Enhancing thermal conductivity of fluids with nano-particles
01 Jan 1995-Vol. 231, pp 99-105
About: The article was published on 1995-01-01 and is currently open access. It has received 7263 citations till now. The article focuses on the topics: Thermal conductivity & Nanoparticle.
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TL;DR: In this article, the effect of Brownian motion on the effective thermal conductivity and viscosity of the nanofluid is calculated by KKL (Koo-Kleinstreuer-Li) correlation, which is then solved numerically by the fourth-order Runge-Kutta integration scheme featuring a shooting technique.
Abstract: The aim of the present paper is to study the nanofluid flow and heat transfer over a stretching porous cylinder. The effective thermal conductivity and viscosity of the nanofluid are calculated by KKL (Koo–Kleinstreuer–Li) correlation. In KKL model, the effect of Brownian motion on the effective thermal conductivity is considered. The governing partial differential equations with the corresponding boundary conditions are reduced to a set of ordinary differential equations with the appropriate boundary conditions using similarity transformation, which is then solved numerically by the fourth-order Runge–Kutta integration scheme featuring a shooting technique. Numerical results for flow and heat transfer characteristics are obtained for various values of the nanoparticle volume fraction, suction parameter, Reynolds number and different kinds of nanofluids. Results show that inclusion of a nanoparticle into the base fluid of this problem is capable to change the flow pattern. It is found that Nusselt number is an increasing function of nanoparticle volume fraction, suction parameter and Reynolds number.
199 citations
TL;DR: In this article, the effect of Brownian motion on the effective thermal conductivity and viscosity of nanofluid is calculated by KKL (Koo-Kleinstreuer-Li) correlation.
Abstract: Control volume based finite element method (CVFEM) is applied to investigate flow and heat transfer of CuO–water nanofluid in presence of magnetic field. The enclosure has a sinusoidal wall under constant heat flux. The effective thermal conductivity and viscosity of nanofluid are calculated by KKL (Koo–Kleinstreuer–Li) correlation. In this model effect of Brownian motion on the effective thermal conductivity is considered. The numerical investigations are conducted at a fixed Prandtl number equal to 6.2. Various values of non-dimensional governing parameters such as volume fraction of nanoparticles (ϕ), Rayleigh number (Ra), dimensionless amplitude of the sinusoidal wall (a) and Hartmann number (Ha) are examined. Also a correlation of Nusselt number corresponding to active parameters is presented. The results show that Nusselt number is an increasing function of nanoparticles volume fraction, dimensionless amplitude of the sinusoidal wall and Rayleigh number while it is a decreasing function of Hartmann number.
198 citations
TL;DR: Both the dispersion process and the use of some dispersants were investigated as a function of the nanoparticle concentration, and the high-pressure homogenization was found to be the best method and the addition of n-dodecyl sulphate and polyethylene glycol as dispersants, respectively, improved the nanofluid stability.
Abstract: In the recent years, great interest has been devoted to the unique properties of nanofluids. The dispersion process and the nanoparticle suspension stability have been found to be critical points in the development of these new fluids. For this reason, an experimental study on the stability of water-based dispersions containing different nanoparticles, i.e. single wall carbon nanohorns (SWCNHs), titanium dioxide (TiO2) and copper oxide (CuO), has been developed in this study. The aim of this study is to provide stable nanofluids for selecting suitable fluids with enhanced thermal characteristics. Different dispersion techniques were considered in this study, including sonication, ball milling and high-pressure homogenization. Both the dispersion process and the use of some dispersants were investigated as a function of the nanoparticle concentration. The high-pressure homogenization was found to be the best method, and the addition of n-dodecyl sulphate and polyethylene glycol as dispersants, respectively in SWCNHs-water and TiO2-water nanofluids, improved the nanofluid stability.
198 citations
Cites background from "Enhancing thermal conductivity of f..."
...The first nanofluids were studied by Choi and Eastman in 1995 [1], to exploit their potentialities, in particular, for heat conduction applications, but until now the studies have not delved into the behaviour of these fluids....
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TL;DR: In this paper, a two-phase mixture model has been chosen to study forced convective heat transfer of nanofluid introducing a new concept of heat transfer enhancement in this article.
198 citations
TL;DR: In this paper, the enhancement in yield of passive double slope solar still (DSSS) using Al2O3 nanoparticles in the basefluid (water) for two different masses 35 kg and 80 kg was presented.
196 citations