Hydrodynamic and thermal analysis of water, ethylene glycol and water-ethylene glycol as base fluids dispersed by aluminum oxide nano-sized solid particles
Abstract:Purpose
The purpose of this paper is to carry out a hydrodynamic and thermal analysis of turbulent forced-convection flows of pure water, pure ethylene glycol and water-ethylene glycol mixture, as base fluids dispersed by Al2O3 nano-sized solid particles, through a constant temperature-surfaced rectangular cross-section channel with detached and attached obstacles, using a computational fluid dynamics (CFD) technique. Effects of various base fluids and different Al2O3 nano-sized solid particle solid volume fra… Show more
“…However, the platelet shape provided the highest frictional entropy generation rate and minimum thermal and total entropy generation rates. Menni et al, [24] inspected the hydrodynamic and thermal behavior of water, ethylene glycol and water-ethylene glycol as base fluids dispersed by aluminum oxide nano-sized solid particles. Boertz et al, [25] used the single-phase approach to model the flow of SiO2/water-Ethylene glycol nanofluids through a heat pipe heat exchanger under a constant heat flux.…”
The convective heat transfer of Al2O3-water nanofluids through a circular tube with a constant heat flux boundary condition is studied numerically. Turbulent flow conditions are considered with a Reynolds number ranging from 3500 to 20000. The numerical method used is based on the single-phase model. Four volume concentrations of Al2O3-water nanoparticles (0.1, 0.5, 1, and 2%) are used with a diameter of nanoparticle of 40 nm. A considerable increase in Nusselt number, axial velocity, and turbulent kinetic energy was found with increasing Reynolds number and volume fractions. However, the pressure losses were also increased with the raise of Re and nanoparticles concentration.
“…However, the platelet shape provided the highest frictional entropy generation rate and minimum thermal and total entropy generation rates. Menni et al, [24] inspected the hydrodynamic and thermal behavior of water, ethylene glycol and water-ethylene glycol as base fluids dispersed by aluminum oxide nano-sized solid particles. Boertz et al, [25] used the single-phase approach to model the flow of SiO2/water-Ethylene glycol nanofluids through a heat pipe heat exchanger under a constant heat flux.…”
The convective heat transfer of Al2O3-water nanofluids through a circular tube with a constant heat flux boundary condition is studied numerically. Turbulent flow conditions are considered with a Reynolds number ranging from 3500 to 20000. The numerical method used is based on the single-phase model. Four volume concentrations of Al2O3-water nanoparticles (0.1, 0.5, 1, and 2%) are used with a diameter of nanoparticle of 40 nm. A considerable increase in Nusselt number, axial velocity, and turbulent kinetic energy was found with increasing Reynolds number and volume fractions. However, the pressure losses were also increased with the raise of Re and nanoparticles concentration.
“…Thermal conductivity enhancement was witnessed for water-based aluminum/aluminum oxide NFs [ 15 ]. In another report, details on the Al 2 O 3 NPs based NFs with pure water, pure ethylene glycol, and water-ethylene glycol mixture, as base fluids are presented in relevance to the hydrodynamic and thermal analysis of turbulent forced-convection flows [ 16 ]. Al 2 O 3 NPs possess the capabilities to function as a heterogeneous Lewis acid catalyst or catalyst support and progress on various catalytic reactions is reviewed [ 17 ].…”
The introduction of toxic chemicals into the environment can result in water pollution leading to the degradation of biodiversity as well as human health. This study presents a new approach of using metal oxides (Al2O3 and SiO2) modified with a plasmonic metal (silver, Ag) nanoparticles (NPs)-based nanofluid (NF) formulation for environmental remediation purposes. Firstly, we prepared the Al2O3 and SiO2 NFs of different concentrations (0.2 to 2.0 weight %) by ultrasonic-assisted dispersion of Al2O3 and SiO2 NPs with water as the base fluid. The thermo-physical (viscosity, activation energy, and thermal conductivity), electrical (AC conductivity and dielectric constant) and physical (ultrasonic velocity, density, refractive index) and stability characteristics were comparatively evaluated. The Al2O3 and SiO2 NPs were then catalytically activated by loading silver NPs to obtain Al2O3/SiO2@Ag composite NPs. The catalytic reduction of 4-nitrophenol (4-NP) with Al2O3/SiO2@Ag based NFs was followed. The catalytic efficiency of Al2O3@Ag NF and SiO2@Ag NF, for the 4-NP catalysis, is compared. Based on the catalytic rate constant evaluation, the catalytic reduction efficiency for 4-NP is found to be superior for 2% weight Al2O3@Ag NF (92.9 Ă 10â3 sâ1) as compared to the SiO2@Ag NF (29.3 Ă 10â3 sâ1). Importantly, the enhanced catalytic efficiency of 2% weight Al2O3@Ag NF for 4-NP removal is much higher than other metal NPs based catalysts reported in the literature, signifying the importance of NF formulation-based catalysis.
“…Kalita et al [36,37] discussed the effect of various emerging parameter on CNT and nanofluids with different shapes. Many recent researches [19][20][21]34,35,[37][38][39] have been done on nanofluids with its powerful effect and found useful conclusions.…”
An analysis is conducted to investigate the problem of heat/mass transfer in MHD free convective flow of Casson-fluid in a vertical channel embedded with saturated porous medium past through carbon nanotubes in the form of single-wall carbon nanotubes (SWCNTs) and multiple-wall carbon nanotubes (MWCNTs) with engine oil as base fluid. In this article, the impact of CNTâs on velocity, temperature, shear stress and rate of heat transfer of the nanofluid has been investigated and studied graphically for the effects of different key physical parameters involved. The validity of this flow model is presented and is found satisfactory agreement with published results. The results state that, fluid velocity accelerates for greater values of Casson parameter and nanoparticles volume fraction, while thermal radiation (R) and heat generation (Q) assume a significant role in CNT's. Applications of this study arise in broad area of science and engineering such as thermal conductivity, energy storage, biomedical applications, air and water filtration, fibers and fabrics.
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