A comparative study of thermal behavior of iron and copper nanofluids

Abstract

Articles you may be interested inEnhancement of thermal conductivity of silver nanofluid synthesized by a one-step method with the effect of polyvinylpyrrolidone on thermal behavior Appl. Phys. Lett. 102, 231907 (2013); 10.1063/1.4809998 Effect of particle size on the thermoluminescence properties of Ba 0.97 Ca 0.03 SO 4 : Cu AIP Conf. Proc. 1512, 446 (2013); 10.1063/1.4791103 Unusual metallic behavior in nanostructured cobalt ferrite at superparamagnetic regime J. Appl. Phys. 112, 063926 (2012); 10.1063/1.4754855Thermal conductivity of polyethylene glycol nanofluids containing carbon coated metal nanoparticles Nanofluids consist of nanoparticles dispersed in heat transfer carrier fluid and are typically used for enhancing thermal conductivity in devices and systems. This study investigated the synthesis of iron and copper nanoparticle-based thermal fluids prepared using a two-step process. Chemical precipitation was used for the synthesis of the powders, and ultrasonic irradiation was used to disperse the nanoparticles in the carrier fluid ͑ethylene glycol͒. The size distributions of the nanopowders in the carrier fluid were determined using dynamic light scattering resulting in average particle sizes of around 500 nm. The crystallite sizes of the powders were below 20 nm. Thus, both types of nanofluids are comparable with regard to crystallite size, particle size, and morphology resulting in a direct comparison of material properties and their effect on thermal conductivity of the nanofluids. A guarded hot parallel-plate method and dynamic tests were used to compare the thermal conductivities of the nanofluids. It was shown that thermal conductivity can be enhanced by up to 70% for copper nanofluids. It was also demonstrated that for a given particle concentration, copper nanofluids are superior in thermal conductivity compared to iron nanofluids.

Mechanisms of pore formation in high-temperature carbides: Case study of TaC prepared by spark plasma sintering

“…TaC 1Àx (henceforth referred to as TaC) was produced by methods we previously developed [41][42][43] to generate powders with average crystallite size of 25 nm from X-ray line broadening, average particle (aggregate) size of 73 nm from dynamic light scattering [44][45][46][47][48][49][50][51][52][53][54][55][56][57], a C/Ta compound ratio of 0.94 (i.e. powders of composition TaC 0.94 ), an oxygen content of $6.1-7.9 wt.%, and a free carbon content of $2.4 wt.% [43].…”

Analysis of Particle and Crystallite Size in Tungsten Nanopowder Synthesis

“…This minimizes multiple scattering even at high particle concentrations. [21] For characterization, approximately 0.0125 g of powder was ultrasonically dispersed for 30 minutes in 25 mL of ethanol without any dispersant. This dispersion was then immediately tested in the instrument.…”

Ionic liquid-based stable nanofluids containing gold nanoparticles

“…Typically, 1.6 ml 1 wt.% sodium citrate aqueous solution was quickly added into 80 ml 0.01 wt.% boiling HAuCl 4 aqueous solution under vigorous stirring for 1/2 h, the color of the solution turned from slight yellow into wine red in less than 2 min and had no variation in the following reaction time, indicating the formation of gold colloid. Quantitative CTABr (3 mmol/l) was added into the aqueous gold colloid under stirring for 1/2 h after it was cooled to room temperature, the colloid was transferred to a separating funnel (250 ml) and 19 6 ] phase with a purplish red color [60]. The bottom phase was separated to a round bottom flask (100 ml) and distilled at reduced pressure for 3 h at 50°C to eliminate the moisture.…”

“…However, the anomalous enhancements of TC were only obtained in carbon nanotube-or metal-based nanofluids with low volume concentrations (vol.%) [11][12][13][14]. Then it is not difficult to understand why these nanofluids have recently been the focus of scientific research [18][19][20].…”