An introduction to heat transfer

A review of the applications of nanofluids in solar energy

This article reports on the International Nanofluid Property Benchmark Exercise, or INPBE, in which the thermal conductivity of identical samples of colloidally stable dispersions of nanoparticles or “nanofluids,” was measured by over 30 organizations worldwide, using a variety of experimental approaches, including the transient hot wire method, steady-state methods, and optical methods. The nanofluids tested in the exercise were comprised of aqueous and nonaqueous basefluids, metal and metal oxide particles, near-spherical and elongated particles, at low and high particle concentrations. The data analysis reveals that the data from most organizations lie within a relatively narrow band (±10% or less) about the sample average with only few outliers. The thermal conductivity of the nanofluids was found to increase with particle concentration and aspect ratio, as expected from classical theory. There are (small) systematic differences in the absolute values of the nanofluid thermal conductivity among the various experimental approaches; however, such differences tend to disappear when the data are normalized to the measured thermal conductivity of the basefluid. The effective medium theory developed for dispersed particles by Maxwell in 1881 and recently generalized by Nan et al. [J. Appl. Phys. 81, 6692 (1997)], was found to be in good agreement with the experimental data, suggesting that no anomalous enhancement of thermal conductivity was achieved in the nanofluids tested in this exercise.

A Benchmark Study on the Thermal Conductivity of Nanofluids

Selection of suitable heat transfer fluid for heat dissipation is an important consideration in the design of heat exchanging systems. Nanofluid, a colloidal mixture made of a base fluid and a nanoparticle, is a new generation of heat transfer fluids becoming a high potential fluid in heat transfer applications due to enhanced thermal conductivity. Research studies about nanofluids are on the rise owing to the mounting interest and demand for nanofluids as heat transfer fluids in a wide variety of applications. Recently, nanofluid technology has a new dimension of impregnating two or more nanoparticles in base fluids, namely hybrid or composite nanofluids. This paper reviews the preparation of metal and metal oxides nanofluids and hybrid nanofluids and the various techniques used to study the physical and chemical characteristics of nanofluids. Thermo-physical and heat transfer properties of nanofluids including the improved thermal conductivity, viscosity and specific heat models for nanofluids are presented. Finally, various application areas of nanofluids, such as transportation, electronic cooling, energy storage, mechanical applications etc. are discussed.

A review on preparation, characterization, properties and applications of nanofluids

Enhanced heat transfer and friction factor of MWCNT–Fe3O4/water hybrid nanofluids

Experimental investigation of thermal–rheological properties and heat transfer behavior of the heat transfer oil–copper oxide (HTO–CuO) nanofluid in smooth tubes

Experimental investigation of flow boiling heat transfer of R-600a/oil/CuO in a plain horizontal tube

Experimental study of condensation heat transfer of R-134a flow in corrugated tubes with different inclinations

Condensation and pressure drop characteristics of R600a in a helical tube-in-tube heat exchanger at different inclination angles

Experimental study of horizontal flattened tubes performance on condensation of R600a vapor

M.A. Akhavan-Behabadi

Papers

Experimental investigation of thermal–rheological properties and heat transfer behavior of the heat transfer oil–copper oxide (HTO–CuO) nanofluid in smooth tubes

Experimental investigation of flow boiling heat transfer of R-600a/oil/CuO in a plain horizontal tube

Experimental study of condensation heat transfer of R-134a flow in corrugated tubes with different inclinations

Condensation and pressure drop characteristics of R600a in a helical tube-in-tube heat exchanger at different inclination angles

Experimental study of horizontal flattened tubes performance on condensation of R600a vapor