Search Results (3)

Nano fluids are widely used today for various energy-related applications such as coolants, refrigerants, and fuel additives. New coolants and design modifications are being explored due to renewed interest in improving the working fluid properties of heat exchangers. Several studies have investigated nanofluids to enhance radiator and heat exchanger performance. A new class of coolants includes single, binary, and tertiary nanoparticle-based hybrid nano-coolants using ethylene glycol/deionized water combinations as base fluids infused with different nanoparticles. This review article focuses on the hydrothermal behavior of heat exchangers (radiators for engine applications) with mono/hybrid nanofluids. The first part of the review focuses on the preparation of hybrid nanofluids, highlighting the working fluid properties such as density, viscosity, specific heat, and thermal conductivity. The second part discusses innovative methodologies adopted for accomplishing higher heat transfer rates with relatively low-pressure drop and pump work. The third part discusses the applications of mono and hybrid nanofluids in engine radiators and fuel additives in diesel and biodiesel blends. The last part is devoted to a summary of the research and future directions using mono and hybrid nanofluids for various cooling applications. Full article

In response to the issues of environment, climate, and human health coupled with the growing demand for energy due to increasing population and technological advancement, the concept of sustainable and renewable energy is presently receiving unprecedented attention. To achieve these feats, energy savings and efficiency are crucial in terms of the development of energy-efficient devices and thermal fluids. Limitations associated with the use of conventional thermal fluids led to the discovery of energy-efficient fluids called “nanofluids, which are established to be better than conventional thermal fluids. The current research progress on nanofluids has led to the development of the advanced nanofluids coined “hybrid nanofluids” (HNFs) found to possess superior thermal-optical properties than conventional thermal fluids and nanofluids. This paper experimentally explored the published works on the application of HNFs as thermal transport media in solar energy collectors and thermal energy storage. The performance of hybrid nano-coolants and nano-thermal energy storage materials has been critically reviewed based on the stability, types of hybrid nanoparticles (HNPs) and mixing ratios, types of base fluids, nano-size of HNPs, thermal and optical properties, flow, photothermal property, functionalization of HNPs, magnetic field intensity, and orientation, and φ, subject to solar and thermal energy storage applications. Various HNFs engaged in different applications were observed to save energy and increase efficiency. The HNF-based media performed better than the mono nanofluid counterparts with complementary performance when the mixing ratios were optimized. In line with these applications, further experimental studies coupled with the influence of magnetic and electric fields on their performances were research gaps to be filled in the future. Green HNPs and base fluids are future biomaterials for HNF formulation to provide sustainable, low-cost, and efficient thermal transport and energy storage media. Full article

In the current industry, coolants are widely used in numerous operations for the purpose of cooling and heat transfer. These operations include all kinds of heat sinks for electronic devices and manufacturing processes such as milling, drilling, turning, and CNC machining. The thermophysical properties of coolants play a vital role in determining the effectiveness of heat transfer and help prevent the components from wear and tear caused by extremely high temperatures. The computational domain consists of a drill bit and rectangular workpiece, and hybrid nanocoolants are sprayed from duplex nozzles. The nanocoolant heat transfer and flow characteristics of the drill bit–workpiece interface were analysed using the large eddy simulation (LES) turbulence model. The workpiece is made of Ti-6Al-4V alloy maintained at a temperature of 1073.15 K. The coolant used is a mineral oil into which different nanoparticles of Al₂O₃, TiO₂, Cu, MWCNT, and SWCNT are dispersed by varying the volume concentration. The variations in temperature, Nusselt number, and wall heat transfer coefficient, with respect to the volume fraction of nanoparticles and the Reynolds number, were investigated. It was concluded that Cu–Al₂O₃ nanoparticles dispersed in mineral oil depicted the most favourable heat transfer. Full article