Phase change materials (PCMs) proved to be valuable and drew the attention of numerous scientists striving to establish novel techniques to minimize energy consumption and expand heat storage; yet a ...number of challenges hampered their research. This paper provides an overall overview on how to overcome those constraints by adapting nano-enhanced phase change materials, the motivation behind their investigation, their advantages, area of applications, and their impact on thermal management and storage equipment. Recent computational and experimental studies have revealed that nanoparticles are extremely useful in terms of improving the thermo-physical properties of PCMs, allowing nano-PCMs, mainly nano-paraffin, to have a major positive influence on thermal concepts at the economical, ecological, and effectiveness levels. In this context, nano-enhanced PCMs are now able to store and release large amounts of heat in short intervals of time, which is relevant to thermal storage systems and contributes to augmenting and boosting their efficiency. It also improves the thermal performance of cooling and heating systems in buildings and regulates the operating temperature of PV systems, electronic components, and batteries.
The current study uses the multi-physics COMSOL software and the Darcy-Brinkman-Forchheimer model with a porosity of ε = 0.4 to conduct a numerical study on heat transfer by Cu-TiO
/EG hybrid ...nano-fluid inside a porous annulus between a zigzagged triangle and different cylinders and under the influence of an inclined magnetic field. The effect of numerous factors is detailed, including Rayleigh number (103 ≤ Ra ≤ 106), Hartmann number (0 ≤ Ha ≤ 100), volume percent of the nano-fluid (0.02 ≤
≤ 0.08), and the rotating speed of the cylinder (-4000 ≤ w ≤ 4000). Except for the Hartmann number, which decelerates the flow rate, each of these parameters has a positive impact on the thermal transmission rate.
Purpose
This paper aims to present a numerical study that investigates the flow of MgO-Al2O3/water hybrid nanofluid inside a porous elliptical-shaped cavity, in which we aim to examine the ...performance of this thermal system when exposed to a magnetic field via heat transfer features and entropy generation.
Design/methodology/approach
The configuration consists of the hybrid nanofluid out layered by a cold ellipse while it surrounds a non-square heated obstacle; the thermal structure is under the influence of a horizontal magnetic field. This problem is implemented in COMSOL multiphysics, which solves the related equations described by the “Darcy-Forchheimer-Brinkman” model through the finite element method.
Findings
The results illustrated as streamlines, isotherms and average Nusselt number, along with the entropy production, are given as functions of: the volume fraction, and shape factor to assess the behaviour of the properties of the nanoparticles. Darcy number and porosity to designate the impact of the porous features of the enclosure, and finally the strength of the magnetic induction described as Hartmann number. The outcomes show the increased pattern of the thermal and dynamical behaviour of the hybrid nanofluid when augmenting the concentration, shape factor, porosity and Darcy number; however, it also engenders increased formations of irreversibilities in the system that were revealed to enhance with the permeability and the great properties of the nanofluid. Nevertheless, this thermal enhanced pattern is shown to degrade with strong Hartmann values, which also reduced both thermal and viscous entropies. Therefore, it is advised to minimize the magnetic influence to promote better heat exchange.
Originality/value
The investigation of irreversibilities in nanofluids heat transfer is an important topic of research with practical implications for the design and optimization of heat transfer systems. The study’s findings can help improve the performance and efficiency of these systems, as well as contribute to the development of sustainable energy technologies. The study also offers an intriguing approach that evaluates entropy growth in this unusual configuration with several parameters, which has the potential to transform our understanding of complicated fluid dynamics and thermodynamic processes, and at the end obtain the best thermal configuration possible.
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