Showing papers on "Thermal published in 2021"
TL;DR: In this article, the thermal properties of AA7072-AA7075/water-based hybrid nanofluid over a curved stretching sheet using non-Fourier heat flux model were analyzed.
142 citations
TL;DR: In this paper, the effect of entropy generation through a non-linear radiative flow of viscous fluid of hybrid nanoparticles over a stretchable rotating disk was explored, where similarity transformations were utilized to reduce the governing problem into the nonlinear ordinary differential equations.
104 citations
TL;DR: In this article, the influence of several variables such as heat distribution methods, thermal and concentration boundary conditions, governing parameters, magnetic field types, numerical schemes, thermophysical correlation types, nanofluid types, slip conditions, Brownian motion, and thermophoresis on the magnetohydrodynamic (MHD) natural convection behaviors of nanofluid in square cavities has been reviewed.
Abstract: The emergence of nanofluids as high-performance thermal transport media has drawn great research attention in the field of heat transfer. Owning to the huge importance of natural convection applications in environmental, agricultural, manufacturing, electronics, aviation, power plants, and industrial processes, heat transfer and flow characteristics of these special fluids in various cavities have been extensively researched. This review paper has paid serious attention to the benefits of controlling the natural convection heat transfer and flow performance of nanofluids in square cavities using magnetic field sources in addition to the aspect ratio, porous media, cavity and magnetic field inclination, hybrid nanofluids, etc. The influence of several variables such as heat distribution methods, thermal and concentration boundary conditions, governing parameters, magnetic field types, numerical schemes, thermophysical correlation types, nanofluid types, slip conditions, Brownian motion, and thermophoresis on the magnetohydrodynamic (MHD) natural convection behaviours of nanofluids in square cavities has been reviewed. The paper focused on the application of numerical and experimental methods to hydromagnetic behaviours of nanofluids in square-shaped enclosures. The concept of bioconvection, bio-nanofluid (green nanofluid), ionic nanofluid, and hybrid nanofluid has also been reviewed in relation to natural convection for the first time. Special cases of MHD natural convection in cavities involving micropolar and hybrid nanofluids are also presented herein. Convective heat transfer in square cavities has been demonstrated to be altered due to the presence of magnetic fields.
104 citations
TL;DR: In this paper, the influence of a two-phase hybrid nanofluid approach on mixed convection characteristics including the consequences of varying Richardson number, number of oscillations, nanoparticle volume fraction, and dimensionless length and position of the solid obstacle was examined.
72 citations
TL;DR: In this paper, the authors demonstrate an approach for augmenting heat transfer through porous media subjected to nonuniform heating during the magnetohydrodynamic flow of a hybrid nanofluid of Cu-Al2O3/water.
Abstract: The intent of this study is to demonstrate an approach for augmenting heat transfer through porous media subjected to nonuniform heating during the magnetohydrodynamic flow of a hybrid nanofluid of Cu–Al2O3/water. The efficacy of such a heating technique is examined utilizing a classical flow geometry consisting of a square cavity. The heating is made at the bottom following a half-sinusoidal function of different frequencies, along with the presence of a uniform magnetic field. The thermal conditions of the cavity, particularly at the bottom wall, drive thermo-hydrodynamics and associated heat transfer. Furthermore, the addition of different types of nanoparticles to the base liquid in order to boost the thermal performance of conventional fluids and mono-nanofluids is a current technique. The coupled nonlinear governing equations are solved numerically in dimensionless forms adapting the finite volume approach, the Brinkman–Forchheimer–Darcy model, local thermal equilibrium and single-phase model. The study is conducted for wide ranges of parametric impacts to analyze global heat transfer performance. The results of this study reveal that the multi-frequency spatial heating during hybrid nanofluid flow can be utilized as a powerful means to improve the thermal performance of a system operating under different ranges of parameters, even with the presence of porous media and magnetic fields. In addition to different heating frequencies, the variations in amplitude (I) and superposed uniform temperature (
$$\theta_{\text{os}}$$
) to half-sinusoidal heating are also examined thoughtfully in the analysis for different concentrations of Cu–Al2O3 nanoparticles. Compared to the base liquid, the hybrid nanofluid can contribute toward higher heat transfer.
70 citations
TL;DR: In this article, the progress, challenges and opportunities in heat transfer research as applied to high-temperature solar thermal and thermochemical energy systems are reviewed, including the fundamentals of concentrated solar energy collection, convective heat transfer in solar receivers, application of liquid metals as heat transfer media, and heat transfer for non-reacting and reacting two-phase solid-gas systems such as particle-gas flows and gas-saturated porous structures.
70 citations
01 Feb 2021
TL;DR: In this paper, the authors reviewed the developments on the application of forced-air convection into battery thermal management system in terms of preheating and cooling and compared the computational fluid dynamics and short-cut methods.
Abstract: With the popularization of lithium ion battery cells, the battery thermal management system (BTMS) has been paid much attention since it is important in ensuring the safety and performance of lithium ion battery pack. Although the BTMS based on the forced-air convection with the advantage of low-cost, simple, and tight design has been favored by practical applications in electric vehicles and electrochemical energy storage stations, the forced-air convection is always criticized for its low cooling efficiency and low-temperature uniformity. Thus, extensive investigation has been conducted to optimize the BTMS based on the forced-air convection. This paper reviews the developments on the application of forced-air convection into BTMS in terms of preheating and cooling. Firstly, the thermal models for battery cells are introduced from the perspective of the lumped model and electrochemical model. Meanwhile, the methods to simulate the flow field are also presented. The computational fluid dynamics and short-cut methods have been compared in the paper. The main optimization route is summarized which includes optimization of pure forced-air convection, the combination with phase change material(PCM), and integration with heat pipe. For the optimization of the pure forced-air convection, four technical routes are concluded, which are the location of inlets and outlets, flowing tunnel, controlling strategy, and flowing state. As for the hybrid BTMS based on forced-air convection with heat pipe and PCM, some extra structures such as mesh or finned structure are also included for enhancing the heat dissipation. Finally, some perspectives and outlooks on BTMS based on the forced-air convection are put forward for future development.
67 citations
TL;DR: In this paper, a numerical study of flow and heat transport of nanoliquid with aggregation kinematics of nanoparticles is carried out using the modified Buongiorno model (MBM).
61 citations
TL;DR: In this paper, a sandwiched configuration of the heat pipes cooling system (SHCS) is suggested for the high current discharging of lithium-titanate (LTO) battery cell.
60 citations
TL;DR: In this paper, the performance of nano-enhanced phase changing materials (nano-PCMs) in terms of their thermal storage properties is investigated for renewable energy-based thermal systems such as solar thermal collectors.
60 citations
TL;DR: In this paper, the use of multiple PCMs of different melting temperatures to provide longer thermal management durations in photovoltaic modules (PVs) is reported as a cost-effective, sustainable approach to overcome the decline in PV conversion efficiency at high operating temperatures.
TL;DR: In this article, the authors developed an integrated numerical model for the optical-thermal-fluid-mechanical analysis of PTRs by coupling Monte Carlo ray-tracing method, finite volume method, and finite element method.
TL;DR: In this paper, the authors presented the concept of a passive thermal management system (TMS) including natural convection, heat pipe, and phase change material (PCM) for electric vehicles.
TL;DR: In this paper, a thermal interface material (TIM), with excellent bulk thermal conductivity and proper elastic modulus, which can fill the gap between contact surfaces, is of great importance to improve overall performance of thermal management in the electronic devices.
TL;DR: In this paper, the inclined magnetically driven Maxwell nanofluid flow on an endless plate was investigated and the governing equation in PDEs involved was converted into higher-order ODEs by utilizing the similarity variables.
TL;DR: In this paper, the effect of helically coiled evacuated tube on the outlet temperature, heat gain, thermal efficiency and pressure losses, has been studied under the normal and reversed system operation.
TL;DR: In this article, a numerical analysis of double diffusive convection in micropolar nanofluids flow governed by peristaltic pumping in an asymmetric microchannel, in the presence of thermal radiation and an external magnetic field is performed.
Abstract: A numerical computation is performed to analyze the double diffusive convection in micropolar nanofluids flow governed by peristaltic pumping in an asymmetric microchannel, in the presence of thermal radiation and an external magnetic field. The highly nonlinear governing equations are diluted by using desirable physical assumptions such as lubrication approximation and low zeta potential. Convective boundary conditions are employed. This enables us to determine numerical estimates of various physical flow variables such as velocity, pressure gradient, spin velocity, temperature of the nanofluid, concentration of solute, and volume fraction of nanoparticles for sundry parameters like micropolar parameter, coupling parameter, solutal Grashof number, thermophoretic diffusion coefficient, Grashof number, thermal radiation parameter and Helmholtz–Smoluchowski velocity with the aid of bvp4c function built-in command of MATLAB 2012b. Influence of each relevant parameter on flow, thermal and species characteristics are computed in this study. Influence of Soret and Dufour parameters are also simulated. This model is applicable to the study of chemical fraternization/separation procedures and various thermal management systems like of heat sinks, thermoelectric coolers, forced air systems and fans, heat pipes, and many more.
TL;DR: In this article, the authors focus on the response of the inclined plate solar collector when the base fluid of water is substituted by the hybrid nanofluid containing MgO (Magnesium oxide), CuO (Copper Oxide), with MWCNTs (Multiple wall carbon nanotubes), and water is used as a base solvent.
TL;DR: In this article, the effects of the porous media on both thermodynamic and hydrodynamic characteristics of the system, i.e., velocity profiles and the pressure drop, were investigated numerically.
Abstract: Photovoltaic-thermal (PVT) collectors, are useful systems to absorb solar energy and convert that to electrical and thermal energy. However, to make the best out of solar irradiation, it is vital to improve the thermal and energy efficiencies of such systems. Porous metal foams are suggested to be utilized in the present study for cooling of the PV cells and increase the thermal and electrical efficiencies. Moreover, the effects of various parameters, such as porous layer thickness, solar heat flux, and Reynolds number on these efficiencies are investigated numerically. Results mainly focus on the effects of the porous media on both thermodynamic and hydrodynamic characteristics of the system, i.e., velocity profiles and the pressure drop. The results indicated that the usage of porous media can improve both efficiencies (between 3 and 4% for the electrical and between 10 and 40% for the thermal efficiency) with a subsequent pressure loss. But for cases with a thickness of more than half of the channel height, it has a negative effect. In the best condition, Rp=0.5, the overall efficiency reaches up to 95%, however, in this case, the pressure drop rises considerably (up to 600 Pa), which causes destructive effects on the system and imposes additional costs.
TL;DR: In this paper, the authors proposed the concept of thermal superposition effect based on the relationship between the cooling efficiency of two hotspots and their relative positions, and the effective cooling area and superposition area describe the thermal characteristics and interaction of hotspots.
TL;DR: The major source of heat from the sun is solar energy, with enormous use of photovoltaic technology, solar power plates, solar energy lights and pumping solar water as discussed by the authors.
Abstract: The major source of heat from the sun is solar energy, with enormous use of photovoltaic technology, solar power plates, photovoltaic lights and pumping solar water. This time is about the analysis...
TL;DR: In this article, the state-of-the-art of the photovoltaic/thermal systems with different loop-pipe configurations and nanoparticles are summarized. And the standpoints, recommendations, and potential future development on the solar photiovoltaic and thermal system with various configurations and nanofluids are deliberated to overcome the barriers and challenges for the practical application.
Abstract: Solar photovoltaic/thermal technology has been widely utilized in building service area as it generates thermal and electrical energy simultaneously. In order to improve the photovoltaic/thermal system performance, nanofluids are employed as the thermal fluid owing to its high thermal conductivity. This paper summarizes the state-of-the-art of the photovoltaic/thermal systems with different loop-pipe configurations (including heat pipe, vacuum tube, roll-bond, heat exchanger, micro-channel, U-tube, triangular tube and heat mat) and nanoparticles (including Copper-oxide, Aluminium-oxide, Silicon carbide, Tribute, Magnesium-oxide, Cerium-oxide, Tungsten-oxide, Titanium-oxide, Zirconia-oxide, Graphene and Carbon). The influences of the critical parameters like nanoparticle optical and thermal properties, volume fraction, mass flux and mass flow rates, on the photovoltaic/thermal system performance are for the optimum energy efficiency. Furthermore, the structure and manufacturing of solar cells, micro-thermometry analysis of solar cells and recycling process of photovoltaic panels are explored. At the end, the standpoints, recommendations and potential future development on the solar photovoltaic/thermal system with various configurations and nanofluids are deliberated to overcome the barriers and challenges for the practical application. This study demonstrates that the advanced photovoltaic/thermal configuration could improve the system energy efficiency approximately 15%-30% in comparison with the conventional type whereas the nanofluid is able to boost the efficiency around 10%-20% compared to that with traditional working fluid.
TL;DR: A boundary layer analysis of three dimensional electromagnetic flows of single and multi walls carbon nanotubes over the surface of a thin needle is addressed in this article, where both single wall and multi wall (MWCNTs) are considered as nanoparticles whereas water is considered as base liquid.
TL;DR: In this paper, the performance of the solar air heater coupled with a finned photovoltaic system as an absorber plate was investigated, and the results showed that the CO2 mitigation of the system using 24, 16, 8, and 8 fins improved by 35.1%, 22.8%, and 10.7%, respectively.
TL;DR: In this paper, the authors investigated the thermal enhancement of a binary eutectic phase change material (PCM), laden with different concentrations of COOH-functionalized Graphene nanoplatelets (f-GNP) for a multi-effect solar cooling thermal storage system.
Abstract: The present work investigates the thermal enhancement of a binary eutectic phase change material (PCM) (150–200 °C), laden with different concentrations of COOH-functionalized Graphene nanoplatelets (f-GNP) for a multi-effect solar cooling thermal storage system. The novel nano-composite is prepared by varying the weight concentration of f-GNP from 1% to 5% in a pristine eutectic salt of LiNO3-KCl (50:50) using the standard nano synthesis protocol. The microstructure, dispersion uniformity are evaluated using scanning electron microscope (SEM) and thermophysical properties of the nano-composite are characterized using dynamic Differential scanning calorimetry (DSC). The thermal conductivity enhancement due to the doping of f-GNP is studied through a series of experimental trials conducted with Laser flash analysis (LFA). The obtained data is plotted and compared with a more robust theoretical thermal conductivity model. It is found that thermal conductivity rises by 104% with f-GNP dispersions, which reflects the improved thermal performance of the storage system. The specific heats of the solid and liquid phase show an increase of 80% & 38% respectively at f-GNP concentration of 5%. Finally, the effect of doping f-GNP on the conjugate heat transfer inside the PCM and fluid flow of HTF is investigated in a vertical shell and tube type storage system, suitable for the double effect solar cooling system. The f-GNP dispersions accelerate the heat storage process with a maximum decrease of 17.3% in the total melt duration. In addition, the role of increased viscosity on the natural convection is simultaneously studied with the increased thermal conduction due to nanoplatelets dispersions.
TL;DR: In this paper, a transient thermo-fluid simulation is developed to analyze the cooling performance characteristics of three BTMSs: liquid cooling (LC), liquid cooling with A-type heat pipes (LCA), and Liquid cooling with B-type Heat Pitches (LCB).
TL;DR: In this paper, a detailed review of the parameters affecting thermophysical performance of PCM-MFs is presented, and the most effective parameters are identified, and all their possible effects are investigated.
Abstract: Many efforts have been made to improve the weak thermal performance of phase change materials (PCMs). Among the common methods of such, embedment of open-cell metal foams (MFs) into PCMs offer unique opportunities to overcome the issue. The composites made of PCMs and MFs (PCM-MFs) have been extensively studied while behaviour of such composites is yet to be fully understood. There are a variety of parameters affecting thermophysical performance of PCM-MFs, some of which are well-known to date, and some are a subject of controversy. This study provides a detailed review of the parameters affecting thermophysical performance of PCM-MFs. In doing so and directed by literature, the most effective parameters are identified, and all their possible effects are investigated. The common observations along with the contradicting reports are pointed out and discussed in detail. Finally, the current gaps in the field are identified and opportunities for further research work to address them are discussed.
TL;DR: In this article, the effects of thermal and concentration convection on the peristaltic transport of Prandtl nanofluids and inclined magnetic field in non-uniform inclined channel is discussed.
TL;DR: In this paper, a thorough review of low-melting-point liquid metal convective heat transfer technologies is presented, where the authors describe typical driving techniques of liquid metals based on electromagnetic, thermal, electrical and magnetic methods.
TL;DR: In this article, the thermal performance of vacuumed copper pipe has been experimentally investigated by using different volume values of 5, 10, 15, and 20 with inclination angles of 45°, 60°, and 90° for variable vacuum pressures.