Study of transport coefficients of nanodiamond nanofluids

Abstract

Abstract. Experimental data on the thermal conductivity coefficient and viscosity coefficient of nanodiamond nanofluids are presented. Distilled water and ethylene glycol were used as the base fluid. Dependences of transport coefficients on concentration are obtained. It was shown that the thermal conductivity coefficient increases with increasing nanodiamonds concentration. It was shown that base fluids properties and nanodiamonds concentration affect on the rheology of nanofluids. IntroductionNanoparticle colloidal suspensions, referred to as 'nanofluids' [1], have potential application in many heat transfer areas because of their intriguing properties such as a considerable increase in thermal conductivity, long-term stability and prevention of clogging in micro-channels [2][3]. Recently extensive efforts have been made to prepare thermal performance enhanced nanofluids [4][5]. Diamond is one of the materials with very high thermal conductivity, and diamond particles are often used as filler in mixtures for upgrading the performance of a matrix [6].In some studies nanodiamonds are used as particles that improve the thermal conductivity of heat-transfer liquids, such as water, oil and ethylene glycol just as particles of metals (gold, copper), metal oxides (aluminum and copper oxides) and silicon carbide [7][8][9][10][11]. It is reasonable to expect that the addition of diamond nanoparticles would lead to thermal performance enhancement in a base fluid. However, available information about them in the open literature is very scant. Torii et al. [12] conducted experiments in nanodiamond-water nanofluids. The authors of work [12] investigated the coefficients of viscosity and thermal conductivity of nanodiamond-water nanofluids. Particle size ranged from 2 to 10 nm were used. Viscosity coefficient of nanofluid with a particle volume concentration of 2% is 55% higher the viscosity coefficient of water. Thermal conductivity coefficient of nanofluid with a particle volume concentration of 5% is 15% higher the thermal conductivity of water.In work [13], nanodiamonds were chosen to form nanofluids with mixture base fluid composed of distilled water with a volume fraction of 0.55 and ethylene glycol with a volume fraction of 0.45. The thermal transport properties, including the thermal conductivity, the viscosity and the convective heat transfer coefficient, were investigated. The thermal conductivity enhancement of nanodiamond nanofluids increases with nanodiamonds loading and the thermal conductivity enhancement is more than 18.0% for a nanofluid at a nanodiamonds volume fraction of 0.02. Viscosity measurements show that the nanodiamond nanofluids demonstrate Newtonian behaviour, and the viscosity significantly decreases with temperature.

A comprehensive review of recent progress of nanofluid in engineering application: Microchannel heat sink (MCHS)

“…The finding is also agreed by another researcher with the statement that the thermal conductivity enhancement is higher using fluid with lower thermal conductivity [58]. The thermal conductivity for various nanoparticles such as titanium oxide, copper oxide, aluminium oxide, and ferrosoferric oxide are 11.7 W/mK, 20 W/mK, 36 W/mK, and 7 W/mK respectively [57].…”