Nanofluid as a coolant for electronic devices (cooling of electronic devices)

Nanofluids are the suspension of ultrafine solid nanoparticles in a base fluid. Nanofluids are expected to be a promising coolant candidate for thermal management system of next generation high heat dissipation electronic systems. Nanofluids are used with different volume fractions. A minichannel heat sink with a 20 x 20 cm bottom is analyzed for SiC-water nanofluid and TiO(2)-water nanofluid turbulent flow as coolants through hydraulic diameters. The results showed that enhancement in thermal conductivity by dispersed SiC in water at 4 volume fraction was 12.44 and by dispersed TiO(2) in water was 9.99 for the same volume fraction. It was found that by using SiC-water nanofluid as a coolant instead of water, an improvement of approximately 7.25-12.43 could be achieved and by using TiO(2)-water 7.63-12.77. The maximum pumping power by using SiC-water nanofluid at 2 m/s and 4 vol. was 0.28 W and at 6 m/S and 4 volume equal to 5.39 W. By using TiO(2)-water nanofluid at 2 m/s and 4 vol. it was found to be 0.29 W and 5.64 W at 6 m/s with the same volume of 4

Cooling of minichannel heat sink using nanofluids

Nanofluids contain a small fraction of solid nanoparticles in base fluids. Nanofluids cooled small channel heat sinks, have been anticipated to be an excellent heat dissipation method for the next generation electronic devices. In this study, nanofluids are used with different volume fractions of nanoparticles as a coolant for the minichannel. Al2O3-water nanofluid and TiO2-water nanofluid were tested for the copper minichannel heat sink, with the bottom of 20 x 20 mm laminar flow as a coolant, through hydraulic diameters. The result showed that adding Al2O3 nanoparticles to water at 4 of volume fractions, enhanced the thermal conductivity by 11.98 and by dispersing TiO2 to the base fluid, was 9.97. It was found that using nanofluid such as Al2O3-water instead of water, improved the cooling by 2.95 to 17.32 and by using TiO2-water, 1.88 to 16.53 was achieved. The highest pumping power by using Al2O3-water and TiO2-water at 4 vol. and 0.1 m/s was 0.000552 W and at 4 vol. and 1.5 m/s was 0.12437 W

Stability, therrno-physical properties, and electrical conductivity of graphene oxide-deionized water/ethylene glycol based nanofluid

Stability, thermal conductivity, viscosity, specific heat, density and electrical conductivity of graphene oxide nanosheets-(60:40) deionized water/ethylene glycol (GONs-DW/EG) were experimentally examined. The stability of the nanofluids is examined with sedimentation time. Experiments were carried out with a weight fraction of (0.01-0.10) and different temperatures. Nanofluids were found to be stable for more than 2 months. The thermal conductivity is improved by 6.67-10.47 at a weight fraction of 0.10 and temperature of (25-45) degrees C. The nanofluids showed a shear thinning behavior at low shear rate; however, it behaved in Newtonian manner with higher shear rate. The viscosity of 0.10 wt. GONs-DW/EG nanofluid is increased by 35 compared to the base fluid at a temperature of 20 degrees C. However, it decreased by 48 with increasing the temperature from 20 to 60 degrees C for the same loading of GONs. The specific heat of the GONs-DW/EG nanofluid increased by 3.59-5.28 with a weight fraction of 0.05 and decreased by 9.05-8.215 with a weight fraction of 0.10 with temperature range of 20-60 degrees C. The density of the GONs-DW/EG nanofluid at weight fraction of 0.10 is decreased by 1.134-1 with temperature of 25-45 degrees C. An improvement in electrical conductivity of about 1664 is achieved at a weight fraction of 0.10 and temperature of 25 degrees C. Correlations were developed for predicting thermo-physical properties and electrical conductivity of the nanofluids based on the experimental data. (C) 2015 Elsevier Ltd, All rights reserved

Thermal conductivity enhancement of nanofluid by adding multiwalled carbon nanotubes: Characterization and numerical modeling patterns

© 2020 John Wiley & Sons, Ltd. Nanofluid is divided in two major section, mono nanofluid (MN) and hybrid nanofluid (HN). MN is created when a solid nanoparticle disperses in a fluid, whereas HN has more than one solid nanomaterial. In this research, iron (III) oxide (Fe3O4) is MN, and Fe3O4 plus multiwalled carbon nanotube (MWCNT) is HN, whereas both are mixed and dispersed into the water basefluid. Thermal conductivity (TC) of Fe3O4/water and MWCNT/Fe3O4/water was measured after preparation and numerical model performed on the resulted data. After that, field emission scanning electron microscope (FESEM) was studied for microstructural observation of nanoparticles. MN and HN TC were studied at temperature ranges of 25 to 50°C and volume fractions of 0.2% to 1.0%. For MN and HN, thermal conductivity enhancement (TCE) of 32.76% and 33.23% was measured at 50°C temperature—1.0% volume fraction, individually. Different correlations have been calculated for numerical modeling, with R2 = 0.9. Deviation of 0.6007% and 0.6096% was calculated for given correlations for MN and HN individually. Deviation of 0.5862% and 0.6057% was calculated for trained models, for MN and HN individually. Thus, by adding MWCNT to Fe3O4-H2O nanofluid, TC is enhanced 0.47%, and this HN has agreeable heat transfer potential