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In this study, a new control of the heat transport process utilizing phase-change materials (PCMs), as latent thermal energy storage, and nanofluid flow in a thermal system is explored numerically. The proposed model comprises PCM domain divided square enclosure, filled with two different nanofluids (TiO2 and CuO) heated and cooled, respectively, at the left and right sides of the enclosure. Horizontal walls are adiabatic. The coupled mathematical model comprises phase-change materials, nanofluids, and thermal gradients, which are solved numerically following the finite volume-based approach. The enthalpy-porosity technique is adopted to assess the melting behavior of the PCM domain. The thermo-hydraulic performance of the complex system of nanofluids and the melting process of PCM is assessed for the set of control variables such as Grashof numbers (Gr) and nanoparticle concentration (ϕ). Analysis revealed that the melting performance of the PCM domain is significantly influenced by the concentration of the nanoparticles on both sides. The results revealed that, for the early stage of the melting process, the thickness of the melted layer strongly depends on the interaction of the thermal gradient inside the cavity. Higher Gr value and ϕ lead to higher thermal convection in the heated section, which allows the faster melting process of the PCM domain and more amount of thermal energy storage inside the PCM. This transport process further enhances with the increase in the nanoparticles concentrations. A higher Gr value with higher nanoparticle concentrations is always beneficial for the higher amount of thermal energy storage and storage goes up to 35.80%. [ABSTRACT FROM AUTHOR]

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Achievement of thermal comfort in air conditioning is a vital issue in the verge of global warming, where it is essential to provide a system that is less harmful to the environment, energy-efficient and economical. In this regard, dehumidification plays an important role in achieving thermal comfort of air conditioning system. Most of the dehumidification systems as of now require high energy and induce negative environmental impacts. Recently a vacuum membrane-based dehumidification has been considered for the alternative air-conditioning system. Development of efficient membranes for the dehumidification operation is indispensable for moisture removal. Typically, the membrane is constructed out of a fine and porous twilled Dutch weave stainless steel wire mesh serving as the support structure laminated with a film of active materials that serve to attract and isolate the moisture from the working air. In this work a combination of nanomaterial and hygroscopic polymer was adopted to improve the film functionality on the wire mesh. In particular, titanium dioxide (TiO2) is coated as intermediate layer on the wire mesh. Further, Polyvinyl alcohol (PVA) and various concentration of potassium formate (KCOOH) were used as the active additive material aiming to increase sensitivity of the membrane towards water vapor. The water vapor and air permeability tests were conducted to investigate the water vapor permeation and air selectivity of the membrane under various air conditions. Morphological and permeance analogy of the produced membrane showed that adding KCOOH enhanced hydrophilicity, which also increased water vapor permeability by 720%. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A prototype data center was created as part of this project. Lauric acid (LA), stearic acid (SA), and undecanoic acid (UA) were blended at a mass of 16%, 10%, and 32%, respectively, to be placed in the system. LA, SA, and UA thermophysical characteristics were examined. The melting temperatures and latent heat values of LA, SA, and UA were determined by differential scanning calorimetry to be 17.13 °C, 71.9 °C, 26.82 °C, and 24.49 °C, respectively, and 190 J g−1, 235 J g−1, 178 J g−1, and 150 J g−1. Thermal conductivities measured with the KD2 Pro were 0.288 W mK−1 for LA, 0.143 W mK−1 for SA, 0.201 W mK−1 for UA, and 0.245 W mK−1 for LA–SA–UA. The heat capacity values for LA, SA, UA, and LA–SA–UA were found to be 22.15 J g−1, 18.82 J g−1, 17.20 J g−1, and 20.49 J g−1, respectively. The findings demonstrate the utility of the LA–SA–UA mixture in energy storage. Thermocouples are deployed in the system at predetermined locations to compare the conditions when the data center is empty and with PCM. At four different speeds (5 m s−1, 4.45 m s−1, 4.25 m s−1, and 2.5 m s−1), empty and PCM cases were compared. 5 m s−1, 4.45 m s−1, 4.25 m s−1, and 2.5 m s−1 PCM system timings were 7800–16440 s, 6960–14,200 s, 5880–11900 s, 4440 s, and 9360 s, respectively. The presence of LA–SA–UA energy storage in the data center is demonstrated in this study. [ABSTRACT FROM AUTHOR]

According to recent research, the theoretical consequences of viscoelastic materials may be adequately described using fractional calculus. A novel model for the fractional time derivative of the Kelvin-Voigt type of viscoelastic semiconductor material has been provided in this study. The Atangana and Baleanu (AB) fractional derivatives operator is utilized, which employs the generalized Mittag–Leffler function as a nonlocal and non-singular kernel and respects all features of fractional derivatives. The Moore–Gibson–Thompson (MGT) photothermal heat transfer model has also been considered to explain the mechanism of photosensitive heat transfer and the interplay between plasma, elastic, and heat signals. This fractional model is used to explore thermal and photoacoustic interactions when an infinite viscoelastic rotating material with a circular cylindrical hole is exposed to a time-dependent variable heat in the presence of an axial constant magnetic field. The solutions of photothermal field variables are obtained using Laplace transform methods, and the technique of Fourier series expansions is applied to obtain the inversions. Results have been listed to examine how the fractional-order and mechanical viscoelastic relaxation parameters affect different photo-thermoelastic variables that have physical meaning. [ABSTRACT FROM AUTHOR]

Computational studies were performed to investigate the melting process in a cubical closed space. Capric acid (CA)–stearic acid (SA) eutectic mixture is chosen as a phase change material (PCM). Some thermo-physical properties such as melting temperature, latent heat of fusion, specific heat capacity, thermal conductivity, thermal expansion coefficient, density and viscosity of CA-SA eutectic mixture prepared as PCM were measured. Considering these measured properties, the melting behavior of the prepared eutectic PCM was simulated numerically with finite volume method in a three-dimensional cavity. Non-isothermal heating conditions throughout phase change process of the PCM are considered in the numerical modeling study. It is shown that temperature difference has a significant impact on the melting, while its behavior changes for various cross sections. It is observed that the melting does not change after 80 min for the studied PCM. Significant variations for the melting behavior are observed between 2D and 3D configurations. Melt fraction is only 1.20% higher in 3D case as compared to 2D case at t = 130 min and Gr = 1.8 × 105, while this value is 1.08% at Gr = 3.6 × 104. [ABSTRACT FROM AUTHOR]

A theoretical model is developed to stimulate electrokinetic transfer through peristaltic movement in a microchannel. The effect of variable viscosity, variable thermal conductivity, and wall properties is carried out. Such flows emerge in bio-mimetic pumping systems at the extremely tiny scale of significance in physiological operation, e.g., eye medication shipment systems. The sinusoidal wave-like motion propagates along the channel wall leading to the peristaltic motion. The long-wavelength and petite Reynolds number estimations are supposed to abbreviate the governing formulas. Debye–Hückel linearization is also analyzed. The variable thermal conductivity and variable viscosity parameters are used as perturbation parameters. The graphical outcomes are presented for temperature, velocity, concentration, and streamlines. Biomedical engineers can use the obtained results to create bio-microfluidic mechanisms that may assist in carrying physical liquids. [ABSTRACT FROM AUTHOR]

Control of heat released during charge/discharge processes of lithium-ion batteries is very important for the improvement of efficiency of lithium-ion batteries. In this study, the thermal performance of a 20 Ah rectangular type battery pack is analyzed with two different cooling fluids, namely water and nanodiamond-Fe3O4 water/ ethylene glycol (ND- Fe3O4 W/EG) hybrid nanofluid. The cooling system has 5 to 25 number of fins while the Reynolds number is taken between 100 and 800. The volume fraction of the nanoparticles is between 0 and 2% while the discharge rates of 3C, 4C and 5C are considered. The findings suggest that increasing the Reynolds number and the nanoparticle volume ratio improves the temperature distribution and lowers the maximum temperature in the battery pack. When compared to water with the same Re number, ND-Fe3O4 + W/EG hybrid nanofluid with 2% volume ratio at 800 Re number provides improvement of maximum temperature by 23.1% while 70.35% improvement in temperature difference is achieved. Using higher number of fins improves the performance. There is a reduction of 13.8% of the temperature difference in the battery pack with 25 fin model as compared to 5 fin model. [ABSTRACT FROM AUTHOR]

In this study, the numerical exploration of heat transfer of non-Newtonian fluid in a ribbed microchannel (MCH) with a pulsating impingement jet is inspected. The coolant is CMC-Water, which is a non-Newtonian fluid. The ribs are intended to be triangular with different angles as 30 ∘ , 40 ∘ and 60 ∘ . The flow is two-dimensional laminar, 50 < Re < 300 . The heat flux is applied to the lower wall of the microchannel. In the study, finite volume method is applied. The obtained results show that the heat transfer increases with increasing Re and decreasing rib angle. Among the four fins considered in the porous state, fin 1(near the MCH inlet) plays an imperative role in increasing heat transfer. Among the porous-nonporous fin arrangements, the state where all four fins are porous has the highest Nusselt number. Jet injection and increased injection velocity from the upper wall of the MCH have improved heat transfer. Jet slot 1 (located near the MCH entrance) has the most significant impact on the increase in heat transfer. When the jet is injected at an angle, in the single-jet mode, the minimum and maximum heat transfer are observed at an angle of 60 ∘ and 90 ∘ , respectively. Among the single-jet, two-jet, and four-jet modes, the best thermal performance has been reported for the four-jet mode with a 90 ∘ spray angle. The use of pulsating jets has a significant effect on improving heat transfer. Among the six combined modes of four pulsating jets (sine, constant and cosine), the highest heat transfer was reported for a pulsating jet with cosine velocity (mode 6). [ABSTRACT FROM AUTHOR]

The successes of miniaturized electronic components are depending on the effective methods used to transfer the heat developed during its working environments. Suspension of nanoparticles in a base fluid is one such method used to control heat generation. Mixing of an optimal percentage of nanoparticles such as Cu, Ag, Al2O3, TiO2, SiC, Fe3O4, and CNT with base fluids is called nanofluids. Ferrofluids are the topic of interest because of the unavailability of naturally accessible magnetic liquids. Augmentation in the thermophysical property of the ferrofluid by considering the known volume with the base fluid made the researcher work on this topic. Recent applications of ferrofluid in the areas like biomedical, microelectromechanical systems (MEMS), nanoelectromechanical systems (NEMS), heat transfer agents, and dampers increase the interest of scientists. Another method of refining the thermal performance of the system is using a porous medium. The study of the generation of entropy and heat and mass transfer enhancement using nanoparticle and porous media is a new area of research nowadays. The use of nanofluid along with the magnetic field finds maximum application in medicine, MEMS, heat exchanges, lubrication, and solar collectors. A comprehensive review of the earlier research has been made by considering the MHD effect on entropy generation and heat and mass transfer studies with ferrofluid flows are presented in this paper. Also, the cavity of different shapes, different heating positions, and blocks inside the cavities are summarized in this review study. [ABSTRACT FROM AUTHOR]

This paper shows the results of a novel research conducted with the overall aim of developing a system that can provide continuous desalination. Productivity enhancement of solar stills is regarded as the main purpose of the investigators in desalination field. This paper represents the experimental results in a new approach of paraffin + graphene oxide nanoparticles mixture. The paraffin mixture in a semicircular, triangular and rectangular absorber with paraffin + graphene oxide of 0.1, 0.3 and 0.5 mass% has been investigated. The finding indicated that for all absorbers, the use of paraffin + graphene oxide in higher mass fractions enhances daily freshwater production. The results showed that the thermal performances are greater applying graphene oxide + paraffin of 0.5 mass% with semicircular absorber compared to triangular and rectangular absorber. The achievement of the present paper can be implemented to design more efficient absorbers for solar still parts. [ABSTRACT FROM AUTHOR]

Current communication candidly explicates the incremental aspect of generated entropy in apermeablesquare enclosure. Porosity aspects are mathematically formulated by Darcy-Forchheimer model, whereas the Lorentz force law is manifested to enclose magnetic field effectiveness. Water is capitalized as base fluid and nanoparticles composed of silver with different nanoparticles volume fractions are obliged. Thermal buoyancy is generated within the flow domain by provision of heat to left boundary. Description about physical modeling of the problem is manipulated in the form of PDEs with boundary constraints. Finite element procedure is used as a solution procedure to sort out the characteristics of flow problem. Variation in thermophysical attributes is presented through stream patterns, isothermal plots against flow contributing variables. Convective heat transfer through boundaries is measured through Nusselt number calculations. [ABSTRACT FROM AUTHOR]

In this study, effects of rotating tube bundle on the hydrothermal performance for the forced convection in a vented cavity are numerically studied with a mixture of Ag and MgO nanoparticles suspended in water, forming a hybrid nanofluid and CNT–water nanofluid. The finite volume method is used for the numerical simulations. The simulation study is performed for various values of Reynolds number (between 100 and 1000), rotational Reynolds number (between − 100 and 100), size (between 0.01H and 0.12H), vertical (between 0.3H and 0.65H) and horizontal locations (between 0.3H and 0.65H) of the cylinder in the tube bundle and nanoparticle volume fraction (between 0 and 0.02). An experimental correlation was used for the description of the Ag–MgO/water hybrid nanofluid. Results indicated that the rotational effects of the tube bundle contribute to the hydrothermal performance. The average Nusselt number enhancements are 8.95% and 40% when CNT–water is used for solid volume fraction of 0.02 at the highest speed, while these values are 31.5% and 37.7% for hybrid nanofluid. The pressure coefficients are higher for negative value of Re ω and hybrid nanofluid. The size of the tube bundle is effective at the highest size, while the increment amount is 16.8% both for CNT–water and for hybrid nanofluids. The center location of the tube bundle resulted in heat transfer enhancement which is in the range of 11% and 18%. As the solid volume fraction of nanoparticles becomes higher, discrepancies between the average Nu values of CNT–water nanofluid and Ag–MgO/water hybrid nanofluid become higher which is also observed for the pressure coefficient. It is advantageous to use CNT particles since higher heat transfer coefficients with lower values of pressure coefficient are obtained. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Forced convection of hybrid Ag–MgO/water nanofluid in a three-dimensional T-shaped vented cavity with multiple ports under the effects of a inner rotating cone and magnetic field is numerically studied with finite volume method. The simulation is performed for various values of parameters such as: Reynolds number (between 100 and 1000), Hartmann number (between 0 and 60), angular velocity of the rotating cone (between − 200 rad/s and 0), aspect ratio of the circular cylinders of the base of the cone (between 0.5 and 2) and nanoparticle solid volume fraction of the hybrid nanofluid ( ϕ 1 between 0 and 0.01, ϕ 2 between 0 and 0.01). It was observed that the average heat transfer rate rises with higher values of Reynolds number, Hartmann number above a specified value, angular rotational speed of the cone, aspect ratio of the cone for values above 1 and solid nanoparticle volume fractions of the hybrid particles. In total, 61% of average heat transfer enhancement for left horizontal upper surface is achieved with the imposed magnetic field. The enhancement in the average Nusselt numbers is 25.6% for the rotating cone at the highest angular velocity as compared to a motionless one. The average heat transfer increases almost linearly with hybrid solid nanoparticle volume fraction, while 8.96% and 15.52% enhancements are obtained for varying the solid volume fraction of the particles with the lower and higher thermal conductivity up to 0.01. [ABSTRACT FROM AUTHOR]

The present work is dedicated to understanding the natural convective flow mechanism and heat exchange under magnetic field within a concentric circular annulus between a heat-generating conductive internal cylinder and an isothermally cold external cylinder filled with a CNTs-water-based nanoliquid. The free convective flow is generated by the temperature gradient created between the inner heat-generating solid cylinder and the outer cold cylinder. The flow equations in their dimensionless form are numerically solved via the technique of finite volume. The dependency of various factors and their interrelationships affecting the thermo-hydrodynamic behavior and heat exchange rate within the system has been delineated. The findings of this study emphasize the role of the considered control parameters with regards to the hydro-thermal characteristics and the heat exchange rate within the annulus. [ABSTRACT FROM AUTHOR]

In this study, jet impingement heat transfer characteristics for a layered nanofluid and porous domains under the effects of inclined uniform magnetic field are examined by using Galerkin weighted residual finite element method. Effects of various pertinent parameters such as Reynolds number (between 100 and 500), Hartmann number (between 0 and 6), magnetic inclination angle (between 0 and 90), Darcy number (between 10 - 4 and 10 - 2 ) and height of porous layer (between 0.25 H and 4 H) on the fluid flow and heat transfer are analyzed. It was observed that local and average heat transfer rate enhance when the value of Reynolds number, magnetic field inclination angle and permeability of the porous layer increase, while the impact is reversed for magnetic field strength. Magnetic field inclination angle has more influence on the convective heat transfer features as compared to strength, and for a horizontally aligned magnetic field heat transfer process is inefficient. When cases in the absence and presence of magnetic field (at Hartmann number of 6) are compared, 28 % of reduction in the average heat transfer is obtained. An optimum value of porous layer height is observed where the highest heat transfer rates are achieved. [ABSTRACT FROM AUTHOR]

Numerical study of evaporation in porous medium during convective drying process was examined, and heat and mass transfer of liquid water and water vapor through porous media was investigated by using the Galerkin weighted residual finite element method. The porous moist object has a rectangular shape and is assumed to represent a food sample. Two-dimensional laminar flow of dry hot air was used in the channel with a rotating circular cylinder. Different locations and angular rotational speed of the rotating cylinder were considered to control the convective heat transfer and mass transportation. The radius of rotating cylinder and velocity of drying air were also varied with five different values. Results showed that rotational angular speed and drying air velocity had significant effect on heat transfer and mass transport phenomenon for the porous moist object. [ABSTRACT FROM AUTHOR]

Forced convection of nanofluid in a vented cavity with elastic bottom wall is studied by using an inner conductive L-shaped object and magnetic field. Simulations are performed using the finite element method when the impacts of various pertinent parameters, such as Reynolds number (between 100 and 500), Hartmann number (between 0 and 40), elastic modulus of the flexible wall (between 10 5 and 10 9 ), solid nanoparticle volume fraction (between 0 and 0.04), size (between 0.1 and 0.4H), inclination (between − 90 and 90) and location ( x c between 0.25 and 0.75 H and y c between 0.15 and 0.65H) of the L-shaped object on the fluid flow and heat transfer features, are investigated. It was observed that wall flexibility effects are influential for the configuration with strong convection and maximum of 11 % enhancement in the average heat transfer rate for the bottom wall is achieved. Suppression of the recirculations in the vented cavity and around the L-shaped object is observed with magnetic field. It is observed that impact of magnetic field on heat transfer enhancement is different for different segments of hot wall. When the cases with the highest magnetic field and in the absence of magnetic field are compared, the average heat transfer enhancement of 5.5 % is achieved for bottom elastic wall while 24.5 % of reduction in the average heat transfer is seen for upper hot wall. The overall Nusselt number reduces slightly when the magnetic field strength is increased. Significant impacts of the size, inclination and location of the of the L-shaped conductive object on the fluid flow such as branching of the main flow stream, size of the vortex below the inlet port and heat transfer are observed. 31.6 % rise of the average heat transfer for left vertical wall and 34.6 % reduction of average heat transfer for bottom wall are achieved when the minimum and maximum of the orientation angles are compared. The location of the L-shaped object has a significant impact on the flow and thermal pattern variations. The highest variation in the contribution to the overall heat transfer is seen for right vertical hot wall segment when the Nusselt numbers at the lowest and highest values of the horizontal and vertical locations of the object are compared. L-shaped object was found to be an efficient tool to control the heat transfer features of the vented cavity. Nanofluid inclusion resulted in heat transfer enhancement in the range of 8.5–16.5% while amount of enhancement is different for different hot wall segments either in the absence or in the presence of magnetic field effects. Finally, a polynomial-type correlation for the average Nusselt number of each hot wall segments of the vented cavity is proposed for water and for nanofluid at ϕ = 0.04 . [ABSTRACT FROM AUTHOR]

This paper presents a novel study on the performance of closed-loop oscillating heat pipe (CLOHP) using iron oxide (Fe3O4) as the working fluid for three types of condensers. The tested CLOHP consists of six turns made of copper tubes, 4.5 mm outer diameter and 3 mm inner diameter with heating power input in a range of 0–200 W. The experimental results showed that the thermal performance of the CLOHPs has been improved when the corrugated horizontal condenser was used compare to straight and corrugated vertical condensers. Based on 800 sets of available experimental data, the results show that the CLOHPs with corrugated horizontal condenser had better thermal performance when charged with Fe3O4/water at 2% mass concentration. [ABSTRACT FROM AUTHOR]

Numerical study of natural convection and melting in a corrugated square cavity filled with CNT-water nanofluid under the influence of inclined magnetic field was performed. The left and right walls of the cavity are kept at constant temperatures while the horizontal wall is adiabatic. Galerkin weighted residual finite element was used. The effects of Hartmann number (between 0 and 40), magnetic inclination angle (between 0° and 90°), nanoparticle volume fraction (between 0 and 4%), number (between 1 and 20) and height (between 0.002 H and 0.16 H) of the corrugation on the convective heat transfer features and melting in the square cavity were examined. Magnetic field was found to dampen the fluid motion, and less movement of the melt front in the upper part of the cavity is observed. By using the CNT nanoparticles in the base fluid, significant enhancement in the heat transfer and faster propagation of the melt front is observed in the absence and presence of magnetic field. Average heat transfer enhancements are around 118% and 95% when nanofluid at the highest particle volume fraction is compared with water in the absence and presence of magnetic field. The heat transfer is reduced and melt front curve characteristics are affected when the number and height of corrugation waves are increased. [ABSTRACT FROM AUTHOR]

This paper explores the heat transfer characteristics and fluid flow of ferrofluid in a channel having non-symmetric cavities under the applied magnetic field. Bottom surface of the cavity is uniformly heated, whereas ceiling of the top cavity is cooled isothermally. The dimensionless governing equations for various physical parameters are computed via a higher-order and stable Galerkin-based finite element technique. Effective governing parameters are nanoparticle volume fraction; (0 ≤ ϕ ≤ 0.15 ), aspect ratio of the cavities; ( 0.2 ≤ h / H ≤ 1.0 ), Richardson number; ( 0.01 ≤ Ri ≤ 10 ), Hartmann number; ( 0 ≤ Ha ≤ 100 ); and Reynolds number; ( 1 ≤ Re ≤ 200 ). It is found that the most important parameter is the geometry such that there is an optimal value to maximize the heat transfer. Moreover, it is also noticed that the heat transfer is reduced with strong magnetic field, namely Hartmann number. [ABSTRACT FROM AUTHOR]

A computational analysis has been performed to study the impact of magnetic field on entropy generation due to mixed convective nanofluid flow with top and bottom side moving lid-driven closed space. The sinusoidal heating was applied to left vertical side, while the right side was under lower constant temperature. Top and bottom sides move in the opposite direction in lateral axis. A monolithic Galerkin finite element approach has been adopted for the spatial discretization and the Crank–Nicolson for the temporal integration of various values of the governing parameters such as magnetic field inclination angle ( 0 ∘ ≤ γ ≤ 90 ∘ ), Hartmann number ( 0 ≤ H a ≤ 100 ), Richardson number ( 0.01 ≤ R i ≤ 10 ) and nanoparticle volume fraction ( 0 ≤ ϕ ≤ 0.04 ). Thus, heat and fluid flow and entropy generation results are presented. It is found that inclination angle of magnetic field plays significant role in fluid flow and heat transfer, and entropy generation is affected slightly by variation of nanoparticles volume fraction. Heat transfer increases almost 400% with the increase in Reynolds number. [ABSTRACT FROM AUTHOR]

In the present study, a computational work has been done to see the heat transfer, fluid flow and temperature distribution in a lid-driven cavity due to an adiabatic rectangular bar with different dimensions and locations. The closed cavity is heated from the bottom wall and cooled from the top while, vertical walls are adiabatic and magnetic field is affected in horizontally. The governing partial differential equations are discretized via monolithic Galerkin finite element method of higher order. The resulting system of nonlinear algebraic equations are linearized at the discrete solution which have been computed utilizing the efficient geometric multigrid linear solver. The influences of various physical parameters on the flow, in specific ranges such as the nanoparticle volume fraction ϕ = 0.04 , length and location of the insulated bar, Reynolds number 1 ≤ R e ≤ 200 , Hartmann number 0 ≤ H a ≤ 100 and Richardson number, 0 ≤ R i ≤ 10 are investigated. It is found that the location of the bar is a good control parameter for heat and fluid flow inside the cavity. Vertical bar position becomes more effective on heat and fluid than that of horizontal bar position, and the presence of the bar becomes insignificant for the lower values of Richardson numbers. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A numerical analysis of natural convection of nanofluid in a wavy-walled enclosure with an isothermal corner heater has been carried out. The cavity is heated from the left bottom corner and cooled from the top wavy wall while the rest walls are adiabatic. Mathematical model has been formulated using the single-phase nanofluid approach. Main efforts have been focused on the effects of the dimensionless time, Rayleigh number, undulation number, nanoparticle volume fraction and length of corner heaters on the fluid flow and heat transfer inside the cavity. Numerical results have been presented in the form of streamlines, isotherms, velocity and temperature profiles, local and average Nusselt numbers. It has been found that nanoparticle volume fraction essentially affects both fluid flow and heat transfer while undulation number changes significantly only the heat transfer rate. [ABSTRACT FROM AUTHOR]