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 paper, the migration characteristics of nanoparticles in the pool boiling process of both nanorefrigerant and nanorefsoil mixture were experimentally studied and numerically simulated, and the deviations between the model predictions and experimental data were in the range of 7.7-38.4%.
Abstract: Migration characteristics of nanoparticles in the pool boiling process of nanorefrigerant and nanorefrigerant–oil mixture are fundamental knowledge for the application of nanorefrigerants in refrigeration systems. In this paper, migration characteristics of nanoparticles in the nanorefrigerant–oil mixture as well as in the nanorefrigerant were experimentally studied and numerically simulated. Experimental results show that the migrated mass of nanoparticles in the pool boiling process of both nanorefrigerant and nanorefrigerant–oil mixture, increase with the increase of the original mass of nanoparticles and the mass of refrigerant; the migration ratio decreases with the increase of volume fraction of nanoparticles; the migrated mass of nanoparticles and migration ratio in the nanorefrigerant are larger than those in the nanorefrigerant–oil mixture. A numerical model, which can qualitatively well predict the migrated mass of nanoparticles, was established, and the deviations between the model predictions and experimental data were in the range of 7.7–38.4%.
107 citations
TL;DR: In this paper, the authors investigated the steady flow and heat transfer of a Cu-Al2O3/water hybrid nanofluid over a nonlinear permeable stretching/shrinking surface with radiation effects.
Abstract: This paper aims to investigate the steady flow and heat transfer of a Cu-Al2O3/water hybrid nanofluid over a nonlinear permeable stretching/shrinking surface with radiation effects. The surface velocity condition is assumed to be of the power-law form with an exponent of 1/3. The governing equations of the problem are converted into a system of similarity equations by using a similarity transformation.,The problem is solved numerically using the boundary value problem solver (bvp4c) in Matlab software. The results of the skin friction coefficient and the local Nusselt number as well as the velocity and temperature profiles are presented through graphs and tables for several values of the parameters. The effects of these parameters on the flow and heat transfer characteristics are examined and discussed.,Results found that dual solutions exist for a certain range of the stretching/shrinking and suction parameters. The increment of the skin friction coefficient and reduction of the local Nusselt number on the shrinking sheet is observed with the increasing of copper (Cu) nanoparticle volume fractions for the upper branch. The skin friction coefficient and the local Nusselt number increase when suction parameter is increased for the upper branch. Meanwhile, the temperature increases in the presence of the radiation parameter for both branches.,The problem of Cu-Al2O3/water hybrid nanofluid flow and heat transfer over a nonlinear permeable stretching/shrinking surface with radiation effects is the important originality of the present study where the dual solutions for the flow reversals are obtained.
107 citations
TL;DR: In this article, a hollow cylinder with a uniformly distributed heat source was used to evaluate the cooling performance of a battery thermal management (BTM) system for electric vehicles, and the simulation results showed that the nanofluid based BTM is able to maintain the temperature.
107 citations
TL;DR: In this article, the authors reviewed the recent trends in the solar concentrating collectors and gave the emphasis on the performance enhancement methods which applied to the concentrating technologies, and concluded that the most effective enhancement methods in the concentrating solar collectors, as well as the future fields that have to be investigated.
Abstract: Solar concentrating solar thermal collectors are promising technologies for various applications which demand medium- and high-temperature levels. The objective of this work is to review the recent trends in the solar concentrating collectors and to give the emphasis on the performance enhancement methods which applied to the concentrating technologies. Optical and thermal enhancements methods are investigated for the following collector types: compound parabolic concentrator, parabolic trough collector, linear Fresnel reflector and solar dish concentrator. The emphasis is given to the utilization of nanofluids as working fluids because a lot of research has been focused on them in the last years. Moreover, the use of internal fins and inserts in the flow, the use of modified absorbers, as well as various optical design optimizations are included in this review. The final conclusions of this work clearly indicate the most effective enhancement methods in the concentrating solar collectors, as well as the future fields that have to be investigated.
107 citations
Additional excerpts
...The term ‘‘Nanofluid’’ has been introduced by Choi at 1995 [6]....
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TL;DR: In this article, the stagnation point flow with variable heat flux is investigated and the effects of physical parameters on velocity and temperature profiles are pointed out, it is observed that velocity profile enhances for larger values of nanoparticles volume fraction.
107 citations