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In fact, local thermal equilibrium (LTE) would be unsuitable when it comes to nuclear reactors, electronic equipment, space devices, geothermal engineering, and high-conductivity foams, due to prominent temperature discrepancy between the two constituents (solid and nanofluid) in porous material. Local thermal non-equilibrium (LTNE) situation may be considered in above real world applications. In view of above relevance, the effects of LTNE model on double-diffusive natural convection (DDNC) within a fluid-saturated porous container loaded with the TiO2-H2O nanofluid and emplacing four cooling and hot channels in Forchheimer-Brinkman-extended Darcy medium have been investigated in the present study. The momentum, heat and mass equations are solved by finite element method. Irreversibility in the two constituents (nanofluid and solid) of the porous structure has been analyzed. The significant outcomes are that fluid circulations enhance due to rise in porosity of the medium. Fluid friction entropy EnFF,T ameliorates significantly by 1514.16 % and 872.97 % with increase in Rayleigh number and porosity of the medium. It is clear that Nuloc,nf,Nuave,nf, Nuloc,s&Nuave,s enhance significantly with rise of buoyancy and thermal conductivity ratio, interstitial solid/fluid heat transfer coefficient.

Significant cooling is an essential requirement in the field of aeronautical and bio-medical engineering, nuclear reactor system, solar collectors, and in development of electronic chips etc. Involving rotating conical geometries. In view of this, flow and heat transfer over conical geometries subject to different constraints of motion are highly needed. Implementation of magnetic field subject to flow pattern controls the fluid motion thereby imparting better cooling. Consideration of nanofluid instead of regular fluid yields prominent cooling of the associated surface. Such relevance has motivated the authors to work on magnetohydrodynamics and heat transfer investigation of water-EG (50:50) mixture based Al2O3 and Fe3O4 past heated and rotating down-pointing upright cone subject to impact of space and temperature varying non-uniform heat source or sink. Numerical solution of dimensionless governing equations is accomplished by implementing Runge-Kutta method. The findings indicate that swirl and axial velocities peter out with rise in magnetic parameter while both exhibit opposite impact in response to slip parameter. Temperature profiles upgrade due to amplification of space and temperature dependent parameters. Skin friction and heat transportation upsurge with growth of solid volume fraction of nanoparticle.

Since performance of thermal systems may depend on fluids’ thermal conductivities being utilized as coolants, improvement of thermal efficiencies of fluids having micro-structures and involving ternary hybrid nanomaterials may be highly valued. In fact, microrotation of ternary hybrid nanofluids (THNFs) in oblique incinerator-shaped chamber may find applications in industrial processes involving polymeric solutions and lubricants where they help in reduction of drag forces and act as better cooling agent. In view of this, the present study carries out thermal and second law dissection of micropolar THNF within an oblique incinerator-shaped chamber heated from bottom emplacing a roundish heater under a fixed heat flux. The THNF comprises of Al2O3, CNT and graphene as nanoparticles. The study reveals that streamlines and isotherms undergo prominent change due to inclination of the chamber. When Raleigh number and diameter of heater amplify streamlines, microrotations, and entropy generation intensify while average Bejan number whittles down. Average heat transfer rate ameliorates by 4.54 % and 2.17 % when total volume fraction augments from 1.5 % to 3 % and 3 %–4.5 %, respectively. Heat transfer rate reduces by 1.23 %, 0.48 %, 3.33 %, 5.24 %, 2.07 %, and 1.66 % when inclination angle increases from 0° to 90° with inclination angle step 15°.

As witnessed worldwide, there has been rapid growth in research and the creation of energy storage devices such as supercapacitor electrodes that can store and deliver energy at a speedy rate, and provide high currents in a short duration. This article deals with a review on how supercapacitor (SC) electrode materials get developed from bio-waste like cooked chicken bone waste (CCBW), chicken egg shells, fish gills, fishbone waste, and biodegradable and non-biodegradable marine wastes such as plastics, mangroves, chitosans, and mussel shells, which provide economic benefit for the substantiality of supercapacitor technology. The synthesis and preparation involved in the study include one step activation and colloidal blending processes. The characterization of the as-prepared materials is carried out by implementing XRD, FESEM, EDS, FT-IR, TGA, TEM, and RAMAN spectroscopy. It is visualized that electrode materials possess high carbon content with porosity leading to a greater specific surface area, which is essential for high conductance SC electrodes. Researche on electrochemical analysis of prepared electrodes from such marine waste materials using CV, GCD, and EIS techniques has been analyzed.

Magnetohydrodynamic free convection liquid considering Hall along with ion-slip current has many engineering usages. In addition, boundary layer flow of power-law fluids due to a stretching plane possesses sundry applications in biological sciences, geophysics, and petroleum industries. Further, hybrid nanofluids are important due to their high heat transfer capability. In view of such relevance, the goal of this investigation is to analyze Hall along with ion-slip effects on thermo-fluidic flow of magnetic power-law hybrid nanofluid so as to accomplish effective cooling in the desired thermal systems. Present investigation’s novelty is adding hybrid nanostructure to power-law fluid flow influenced by Hall and ion-slip mechanism and implementation of modified Fourier’s law featured with velocity and temperature gradients. The key results are that fluid velocity amplifies with rise in ion-slip and Hall parameters. Modified Prandtl numbers and Hall parameter ameliorate heat transfer rate while ion-slip parameter diminishes it.

The study of natural convection and heat transfer in a trapezoidal cavity finds a wide range of technological applications including thermal energy storage systems, building ventilation/insulation, waste heat recovery, electronic device cooling, controlling PV panel temperature, energy conservation, exchangers, nuclear reactors, furnaces, glass production, food processing, and drying technologies. The purpose of the current study is to explore the entropy and natural convection of non-Newtonian nano-encapsulated phase change material (NEPCM) suspension in a saturated porous medium enshrouded in a trapezoid-shaped domain with three heated blocks fitted with the bottom surface. The novelty of the present work is the introduction of power-law (Ostwald-de Waele) model subject to NEPCM suspension in trapezoidal enclosure emplacing three heated fins at its bottom surface embedded in Brinkman-Forchheimer extended Darcy medium with variant porosity. The finite element method is implemented to solve the governing equations numerically. The important findings of the present study include streamlines, isotherms, velocities, and apparent viscosity enhance while entropy generation whittles down with rise in Darcy number. Entropy generation ameliorates by 519.16 % for low to high porosity of Brinkman-Forchheimer extended Darcy medium. The maximum apparent viscosity augments by 1441.24 % when power law index ameliorates.

The present work deals with thermal aspect and entropy of ternary hybrid nanofluid (Graphene, Al2O3, and MWCNT as nanoparticles and water as base fluid) inside an inclined domain considering heat generation/absorption. The domain possesses triangle-shaped corrugated walls with variable height and a semi-circular heater located on its bottom wall. Finite element method (FEM) is employed to acquire a well-defined solution of the non-dimensional governing equations along with the boundary conditions. The influence of the pertinent parameters along with their ranges (0.2≤b≤0.3), (105≤Ra≤106), (0o≤η≤90o), (−1≤Hs≤1) has been studied. Some striking outcomes of the present investigation are that streamlines and entropy generation (EnT) peter out while local Nusselt number (Nuloc) and average Bejan number (Beave) ameliorate with rise in dimensionless height of the corrugated wall (b). The absolute maximum values of vertical and horizontal velocities of ternary hybrid nanofluid enhance by 96.47 % and 29.5 %, respectively, when inclination angle (η) increases from 45o to 90o. It is visualized that Nusselt number is maximum subject to heat sink while it attains a minimum value in response to heat source. Because of triangle shaped corrugated walls and ternary hybrid nanofluid, the present problem contributes superior cooling in thermal systems featured with such complex geometry in industries.

The present study analyzes on the reviews carried out by the previous researchers on the entropy generation caused by the flow and heat transfer of several composite nanofluids subject to varieties of geometries under the influence of several constraints of motions. The composite nanofluids include binary hybrid nanofluids and ternary hybrid nanofluids involving disparate base fluids with different suitable nanoparticles. The geometries considered are deformed surfaces (stretched/shrunk sheets, cylinders, and disks), channels and cavities. Several numerical techniques such as Runge-Kutta method and finite element/difference/volume methods are implemented in the investigations. The major and significant outcome of the review analysis is the entropy comparison for different types of nanofluids. Growth of the volume percentage of nanoparticles at a fixed mass flow rate enhances entropy formation. When porosity strength increases, the irreversible entropy production caused by fluid friction results in increased thermal efficiency of certain systems than magnetic entropies. Compared to single nanofluids, hybrid nanofluids display the maximum entropy. With increasing Rayleigh numbers, the frictional and magnetic entropies in composite nanofluids ameliorate significantly than thermal entropy.

The present work may deal with the flow, heat transfer and entropy dissections of hydromagnetic buoyancy-driven nanoliquid inside a diamond-shaped container considering ⊥- shaped obstacle of varying configurations subject to heat/sink source and porous matrix. The importance of the above problem is due its potential utilizations in modern industries such as thermal extrusion systems, solar energy collectors, heat exchangers, microelectronic cooling, automobiles, building ventilation, bio-medicine etc. The equations governed may well be solved via finite element method. The present work's novelty would be the introduction of ⊥- shaped obstacle of varying configurations in a diamond shaped cavity embodying a porous matrix and analyzing the flow along with heat transfer aspects there in. The main findings are that alteration of flow nature from hydrodynamic to hydromagnetic whittles down streamlines and augments isotherms at given Rayleigh number in presence of source/sink subject to porous medium. Total entropy exhibits 3896 % enhancement and average Bejan number shows sharp 85.5 % diminution due to rise of Rayleigh number. The outcomes of the present study finds effective and persistent industrial cooling due to better stability of alumina nanoparticles in nanofluid involved in complex geometries like diamond shaped cavities which is the beyond of existing literature.