Thermal and thermo‐hydraulic behaviour of alumina‐graphene hybrid nanofluid in minichannel heat sink: An experimental study

Abstract

Summary Thermal and pressure drop aspects of a minichannel heat sink have been investigated experimentally using distilled water as base fluid with alumina, graphene and alumina‐graphene hybrid composition at 0.01% volume concentration. The reasons to select alumina‐graphene as a potential nanomaterials combination for hybrid nanofluids are as: (i) thermal conductivity enhancement and (ii) to investigate the effect of morphology (shape and size of nanoparticles). Alumina (Al2O3) is oxide and has spherical shape whereas graphene is allotrope of carbon and has platelet shape. To examine the effect of different nanoparticles (in terms of shape, size and properties) dispersed hybrid nanofluid on hydrothermal bahaviour is an interesting study. Effects of Reynolds number (80‐450), flow rate (0.1‐0.5 L/min) and fluid inlet temperature (20‐40°C) are studied. The effects of uniform heat flux of 50 and 66.7 W/cm2 on hydrothermal behaviour of a minichannel are also examined. The increment in convective heat transfer coefficient (HTC) is 30.93% at 30°C with graphene/water composition nanofluid than water base fluid. A penalty of 23.82% has been observed in pressure drop with graphene/water nanofluid over base fluid. As inlet temperature increases, Nusselt number (Nu) increases while adverse effect is found in case of friction factor. Performance evaluation criteria (PEC) has been observed more than 1 for all nanofluids and hybrid nanofluids, which ensured that nanofluids act as a better electronic cooling agent than water. Al2O3 + graphene hybrid nanofluid delivers optimum comparison factor (HTC to pressure drop ratio) and lower entropy generation rate among used working fluids. Graphene/water nanofluid yields less comparison factor compared to other working fluids irrespective of high HTC. h/Δp is favourable for nanofluid of unlike particles of hybrid composition (in terms of particle size, properties and shape) as compared to mono nanofluid and hybrid nanofluid having similar particles.

Enhancement of Thermo-Hydraulic Performance using Water-Based Alumina Nanofluids: A Numerical Investigation

“…The cold-water temperature increased along the heat exchanger's length. Verma M et al [21] Geopolymer concrete (GPC) is a sustainable and environmentally friendly alternative to conventional concrete. It forms a geopolymer bond, unlike regular concrete, which forms a calcium silicate hydrate bond.…”

Heat transfer enhancement of Fe 3 O 4 ‐water nanofluid by the thermo‐magnetic convection and thermophorestic effect

“…The augment of the heat transfer by magnetic field has caught more extensive attention because nuclear reactions and liquid metal cooling in nuclear energy system are often magnetically controlled. Another approach to augment the heat transfer of MCHS is replaced the traditional working fluid by nanofluid due to the higher thermal conductivity (TC) 10,11 . It is especially suitable in microdevices 12 .…”

“…Another approach to augment the heat transfer of MCHS is replaced the traditional working fluid by nanofluid due to the higher thermal conductivity (TC). 10,11 It is especially suitable in microdevices. 12 The underlying reason for ameliorating TC of nanofluids is the behaviors of nanoparticles, including Brownian motion, 13 thermophoresis, 14 nanolayer, 15 aggregation, 16 and so on.…”

Design of Novel Cooling Systems Based on Metal Plates with Channels of Shapes Inspired by Nature

“…In this sense, some works related to microchannels technology are focused on increasing the thermal conductivity of the cooling fluid by introducing nanoparticles with higher thermal conductivity in the fluid, generating the so-called nanofluids. This enhancement of the heat transfer properties of the nanofluids implies an increment on the convective heat transfer coefficient, improving the heat dissipation [10,11]. Nevertheless, the use of these fluids also produces an increment in the pressure drop due to the higher density and viscosity of nanofluids, penalizing the ratio of heat transfer dissipation to pumping power supply.…”