Investigation of thermal characteristics of CNF-based nanofluids for electronic cooling applications

Abstract

A major problem being faced by existing coolants is the limited amount of heat that can be absorbed by the fluids. An innovative way to overcome this limitation is by utilizing a nano-coolant as a heat transfer medium in a cooling application. This paper was aimed at formulating an efficient nanofluid from Pyrograf III HHT24 carbon nanofibers (CNF) in a base fluid consisting of deionized water (DI) and ethylene glycol (EG) with polyvinylpyrrolidone (PVP) as the dispersant. The experiment was conducted by setting the variable weight percentage of CNF from 0.1 wt% to 1.0 wt%, with the base fluid ratio of 90:10 (DI:EG) weight percent. Then, the thermal properties of the formulated nanofluids were investigated. The test on the thermal conductivity of the nanofluids showed that the highest thermal conductivity of 0.642 W/m.K in this experiment was produced when the concentration of nanofluid is 0.5 wt% at a temperature of 40°C. Experimental investigations into the forced convective heat transfer performance of the CNF-based nanofluid in a laminar flow through a mini heat transfer test rig showed that the presence of nanoparticles enhanced the heat transfer coefficient as opposed to the original base fluid. The highest heat transfer coefficient was reported using nanofluid with a concentration of 0.6 wt% at 40°C. The enhancement of the heat transfer coefficient was due to the higher thermal conductivity value. The Nusselt number was also calculated and presented in this paper. This study showed that the CNF-based nanofluids have a huge potential to replace existing coolants in electronic cooling applications. Thus, in order to commercialize nanofluids in practice, more fundamental studies are needed to understand the crucial parameters that affect their thermal characteristics.

Investigation of thermal and hydrodynamic behaviour of Al2O3-water nanofluid through a rough parallel plate

“…Nanofluids are popular heat transfer fluids made up of a base fluid and nanoparticles. The execution of nanoparticles into heat transfer base fluid significantly enhances the heat transfer performance of the working fluids [2][3][4][5][6][7]. Solid nanoparticles have a higher thermal conductivity which supports the overall thermal and hydrodynamic properties of the heat transfer fluid as investigated by Li et al [8] and Cheng et al [9].…”

Heat and Flow Characteristics of Nanofluid Flow in Porous Microchannels

“…To achieve convection performance enhancement, synergy angle β' (º) needs to be decreased in order to increase the left-hand-side term of Eq. (29). For the ideal case of cos β' = 1, the heat and flow fields are at the highest degree of synergy.…”

“…(28) can be used for the non-dimensionalization of Eq. (27) to obtain: (29) The dot product of the convection term in Eq. (29) can be written as Eq.…”

“…Besides, convection performance can be further increased through the suspension of high-thermal-conductivity nanoparticle in conventional coolant [15][16][17][18]. This innovative type of fluid is coined as nanofluid which displays an exceptional potential in increasing the convection performance [19][20][21][22] because of the intensified synergy between the heat and flow fields [23][24][25][26][27][28][29].…”

Titanium oxide with nanocoolant for heat exchanger application

“…Thermal properties of the nanofluid are mainly dependent on the metal nanoparticle properties. When metal nanoparticles are dispersed into the carrier liquids, the heat transfer efficiency of the fluid compared to the carrier liquid by itself increases [24][25][26][27][28]. Theoretically, the improvement can be up to 350% because compared to liquid such as water or other organic fluids, metal has a much higher thermal conductivity, no matter what state it stays at.…”