Thermal Conductivity Enhancement of Metal Oxide Nanofluids: A Critical Review

Abstract

Advancements in technology related to energy systems, such as heat exchangers, electronics, and batteries, are associated with the generation of high heat fluxes which requires appropriate thermal management. Presently, conventional thermal fluids have found limited application owing to low thermal conductivity (TC). The need for more efficient fluids has become apparent leading to the development of nanofluids as advanced thermal fluids. Nanofluid synthesis by suspending nano-size materials into conventional thermal fluids to improve thermal properties has been extensively studied. TC is a pivotal property to the utilization of nanofluids in various applications as it is strongly related to improved efficiency and thermal performance. Numerous studies have been conducted on the TC of nanofluids using diverse nanoparticles and base fluids. Different values of TC enhancement have been recorded which depend on various factors, such as nanoparticles size, shape and type, base fluid and surfactant type, temperature, etc. This paper attempts to conduct a state-of-the-art review of the TC enhancement of metal oxide nanofluids owing to the wide attention, chemical stability, low density, and oxidation resistance associated with this type of nanofluid. TC and TC enhancements of metal oxide nanofluids are presented and discussed herein. The influence of several parameters (temperature, volume/weight concentration, nano-size, sonication, shape, surfactants, base fluids, alignment, TC measurement techniques, and mixing ratio (for hybrid nanofluid)) on the TC of metal oil nanofluids have been reviewed. This paper serves as a frontier in the review of the effect of alignment, electric field, and green nanofluid on TC. In addition, the mechanisms/physics behind TC enhancement and techniques for TC measurement have been discussed. Results show that the TC enhancement of metal oxide nanofluids is affected by the aforementioned parameters with temperature and nanoparticle concentration contributing the most. TC of these nanofluids is observed to be actively enhanced using electric and magnetic fields with the former requiring more intense studies. The formulation of green nanofluids and base fluids as sustainable and future thermal fluids is recommended.

Temperature‐dependent electrical conductivity impact on radiative and dissipative peristaltic transport of boron nitride‐ethylene glycol nanofluid through asymmetric channels

“…The following are the possible expressions for the governing equations of the flowing underneath study in laboratory frame $$( {X,Y} )$$ become [52– 56, 59, 60, 67–69]:…”

“…According to Zeeshan et al [41], a complicated travelling wave with zeta potential and a heat source was used to generate the electroosmosis-modulated bio flow of nanofluid through a rectangular peristaltic pump. Several attempts to describe the use of nanofluid and peristaltic flow could be identified in the literature [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56].…”

Spherical Hybrid Nanoparticles for Homann Stagnation-Point Flow in Porous Media via Homotopy Analysis Method

“…Research on the effects of nanofluid type, nanoparticle concentration, and nanofluid depth on solar cell performance was reviewed by Modi et al [ 15 ]. How nanofluids can be applied to solar cells and various enhancement techniques have also been discussed [ 16 ]. As part of their experimental investigation, Jana et al [ 17 ] explored the impact of hybrid nanoparticles on fluid heat transfer.…”

A computational convection analysis of SiO2/water and MoS2‐SiO2/water based fluidic system in inverted cone

“…The single‐phase modeling approach of NFs is especially important for lubricant refining, coolants, and applications in daily life including portable computer systems, air conditioners, coolers, and nanostructures 1 . In the manufacturing industry, solar thermal collectors are recognized as a highly straightforward and environmentally friendly way to convert UV irradiation to heat energy 2,3 . In such collectors, various fluids such as glycol and water are used to improvise their performance and power 4,5 .…”

“…1 In the manufacturing industry, solar thermal collectors are recognized as a highly straightforward and environmentally friendly way to convert UV irradiation to heat energy. 2,3 In such collectors, various fluids such as glycol and water are used to improvise their performance and power. 4,5 Recently, numerically and experimentally, several researchers have researched the use of NFs in many kinds of solar collectors.…”