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

Flow and heat transfer characteristics of magnetic nanofluids: A review

Electronics cooling with nanofluids: A critical review

The expectation of sustainable development of energy and environment has widely attracted public׳s attention, and the high-efficiency heat transfer device is greatly needed. As a new heat transfer device, pulsating heat pipe (PHP) has been considered have a bright prospect due to its obvious advantages – simple structure, low cost and excellent heat transfer capability. A number of experimental and theoretical researches have been conducted on PHP in the past decades since it was proposed by Akachi in 1990. However, due to the hydrodynamic and thermodynamic coupling effect, the operational mechanism of PHP is extremely complex and has not been completely revealed so far. With great expectation of applications for the PHP in the near future, this paper attempts to review the development of PHP on the basis of systematic summary of the latest results of both experimental and theoretical studies. Meanwhile, some promising and innovatory applications of the PHP are also reported. This paper is expected to provide basic reference for future researches.

Review of the development of pulsating heat pipe for heat dissipation

Phase change materials (PCMs) have huge potential for latent thermal energy storage, waste heat recovery, heating, and cooling systems, due to their excellent thermal storage properties. However, the low thermal conductivity is most significant problem related with the PCMs, which retards the heat transfer rate and limits their practical applications. Heat pipe (HP) is extensively used heat transferring device, due to their ability to transfer heat isothermally over small and large distances. This review focuses on the systems that use a combination of PCM and heat pipes to enhance thermal performance and efficiencies. Overall efficiency, heat storage and release rate of PCM is reported to greatly improve by the integration of HP. These hybrid systems also have shown to overwhelm the issues such as low thermal conductivity of PCM and overheating of heat pipes.

Applications of combined/hybrid use of heat pipe and phase change materials in energy storage and cooling systems: A recent review

Currently, the thermal management of microelectromechanical systems (MEMS) has become a challenge. In the present research, a micro pulsating heat pipe (MPHP) with a hydraulic diameter of 508lm, is experimented. The thermal performance of the MPHP in both the transient and steady conditions, the effects of the working fluid (water, silver nanofluid, and ferrofluid), heating power (4, 8, 12, 16, 20, 24, and 28W), charging ratio (20, 40, 60, and 80%), inclination angle (0 deg, 25 deg, 45 deg, 75 deg, and 90 deg relative to horizontal axis), and the application of magnetic field, are investigated and thoroughly discussed. The experimental results show that the optimum charging ratio for water is 40%, while this optimum for nanofluids is 60%. In most of situations, the nanofluid charged MPHPs have a lower thermal resistance relative to the water charged ones. For ferrofluid charged MPHP, the application of a magnetic field substantially reduces the thermal resistance. This study proposes an outstanding technique for the thermal management of electronics. [DOI: 10.1115/1.4023847]

Zahra Shiee

Papers

Promising Technology for Electronic Cooling: Nanofluidic Micro Pulsating Heat Pipes