K. Thirumalaisamy and A. Subramanyam Reddy
The analysis of fluid flow and thermal transport performance inside the cavity has found numerous applications in various engineering fields, such as nuclear reactors and solar…
Abstract
Purpose
The analysis of fluid flow and thermal transport performance inside the cavity has found numerous applications in various engineering fields, such as nuclear reactors and solar collectors. Nowadays, researchers are concentrating on improving heat transfer by using ternary nanofluids. With this motivation, the present study analyzes the natural convective flow and heat transfer efficiency of ternary nanofluids in different types of porous square cavities.
Design/methodology/approach
The cavity inclination angle is fixed ω = 0 in case (I) and
Findings
The average heat transfer rate is computed for four combinations of ternary nanofluids:
Practical implications
The purpose of this study is to determine whether the ternary nanofluids may be used to achieve the high thermal transmission in nuclear power systems, generators and electronic device applications.
Social implications
The current analysis is useful to improve the thermal features of nuclear reactors, solar collectors, energy storage and hybrid fuel cells.
Originality/value
To the best of the authors’ knowledge, no research has been carried out related to the magneto-hydrodynamic natural convective
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Ali Ahmadi Azar, Payam Jalili, Bahram Jalili and D.D. Ganji
This study examines fluid flow within a rectangular porous medium bounded by walls capable of expansion or contraction. It focuses on a non-Newtonian fluid with Casson…
Abstract
Purpose
This study examines fluid flow within a rectangular porous medium bounded by walls capable of expansion or contraction. It focuses on a non-Newtonian fluid with Casson characteristics, incompressibility, and electrical conductivity, demonstrating temperature-dependent impacts on viscosity.
Design/methodology/approach
The flow is two-dimensional, unsteady, and laminar, influenced by a small electromagnetic force and electrical conductivity. The Hybrid Analytical and Numerical Method (HAN method) resolves the constitutive differential equations.
Findings
The fluid’s velocity is influenced by the Casson parameter, viscosity variation parameter, and resistive force, while the fluid’s temperature is affected by the radiation parameter, Prandtl number, and power-law index. Increasing the Casson parameter from 0.1 to 50 results in a 4.699% increase in maximum fluid velocity and a 0.123% increase in average velocity. Viscosity variation from 0 to 15 decreases average velocity by 1.42%. Wall expansion (a from −4 to 4) increases maximum velocity by 19.07% and average velocity by 1.09%. The average fluid temperature increases by 100.92% with wall expansion and decreases by 51.47% with a Prandtl number change from 0 to 7.
Originality/value
Understanding fluid dynamics in various environments is crucial for engineering and natural systems. This research emphasizes the critical role of wall movements in fluid dynamics and offers valuable insights for designing systems requiring fluid flow and heat transfer. The study presents new findings on heat transfer and fluid flow in a rectangular channel with two parallel, porous walls capable of expansion and contraction, which have not been previously reported.
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Arooj Tanveer, Sami Ul Haq, Muhammad Bilal Ashraf, Muhammad Usman Ashraf and R. Nawaz
This study aims to numerically investigate heat transport in a trapezoidal cavity using hybrid nanoparticles (Ag-$Al_2O_3$). Unlike previous studies, this one covers…
Abstract
Purpose
This study aims to numerically investigate heat transport in a trapezoidal cavity using hybrid nanoparticles (Ag-$Al_2O_3$). Unlike previous studies, this one covers magnetohydrodynamics, joule heating with viscous dissipation, heat absorption and generation. The left and right sides of the chasm are frigid. The upper wall heats, whereas the bottom wall remains adiabatic.
Design/methodology/approach
After reducing the system of dimensional equations to dimensionless equations, the authors use the Galerkin finite element method to solve them numerically. Geometric parameters affect heating efficiency; thus, the authors use flow metrics such as the Reynold number Re, magnetic parameter M, volume fraction coefficient, heat absorption and Eckert number Ec. The authors use the finite volume method to solve the governing equations after converting them to dimensionless form. The authors also try the artificial neural network method to predict the innovative cavity’s heat response in future scenarios. Transition state charts, regression analysis, MSE and error histograms accelerate, smooth and accurately converge solutions.
Findings
As the magnetic parameter and Eckert number increase, the enclosure emits more heat. As Reynold and volume fraction coefficients rise, the Nusselt number falls. It rose as magnetic, Eckert and heat absorption characteristics increased. The average Nusselt number rises with Reynolds and volume fraction coefficients. The magnetic, Eckert and heat absorption characteristics have inverse values.
Originality/value
This study numerically investigates heat transport in a trapezoidal cavity using hybrid nanoparticles (Ag-$Al_2O_3$). Unlike previous studies, this one covers MHD, joule heating with viscous dissipation, heat absorption and generation. The left and right sides of the chasm are frigid. The upper wall heats, whereas the bottom wall remains adiabatic.
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The investigation of fluid flow over a rotating disk has been increasing due to the spread of machine technology. Because of this development, we scrutinized the…
Abstract
Purpose
The investigation of fluid flow over a rotating disk has been increasing due to the spread of machine technology. Because of this development, we scrutinized the Magnetohydrodynamic (MHD) flow of hybrid nanofluid caused by a decelerating rotating disk with Ohmic heating, Soret and Dufour effects. The disk's angular velocity is taken to be an inversely time-dependent linear function. Moreover, the temperature-dependent viscosity of hybrid nanofluid is incorporated in the present investigation. Methanol is considered as base fluid, while copper oxide (CuO) and magnesium oxide (MgO) are nanoparticles.
Design/methodology/approach
Estimated fundamental partial differential equations of flow problems are altered as a dimensionless system of ordinary differential equations using appropriate similarity transformation and solved using a numerical technique: BVP Midrich scheme in Maple software. The impression of emerging non-dimensional parameters is portrayed graphically. All outcomes are shown in the velocity, temperature and concentration profiles.
Findings
The developed flow problem involves a non-dimensional parameter (A) that reveals the deceleration of the disk. For larger values of A, the disk decelerates faster and for some fixed time, the fluid surrounding the disk revolves more rapidly than the disk itself. The radial velocity of fluid diminishes and axial velocity becomes uniform when the disk is subjected to wall suction velocity (B).
Originality/value
This analysis is significant in biomedical engineering, cancer therapeutic, manufacturing industries and nano-drug suspension in pharmaceuticals. The novelty of the current study is the hybrid nanofluid flow with Ohmic heating, Soret and Dufour effects on a decelerating rotating disk. To the best of the author's knowledge, no such consideration has been published in the literature.
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In recent times, there has been a growing interest in buoyancy-induced heat transfer within confined enclosures due to its frequent occurrence in heat transfer processes across…
Abstract
Purpose
In recent times, there has been a growing interest in buoyancy-induced heat transfer within confined enclosures due to its frequent occurrence in heat transfer processes across diverse engineering disciplines, including electronic cooling, solar technologies, nuclear reactor systems, heat exchangers and energy storage systems. Moreover, the reduction of entropy generation holds significant importance in engineering applications, as it contributes to enhancing thermal system performance. This study, a numerical investigation, aims to analyze entropy generation and natural convection flow in an inclined square enclosure filled with Ag–MgO/water and Ag–TiO2/water hybrid nanofluids under the influence of a magnetic field. The enclosure features heated slits along its bottom and left walls. Following the Boussinesq approximation, the convective flow arises from a horizontal temperature difference between the partially heated walls and the cold right wall.
Design/methodology/approach
The governing equations for laminar unsteady natural convection flow in a Newtonian, incompressible mixture is solved using a Marker-and-Cell-based finite difference method within a customized MATLAB code. The hybrid nanofluid’s effective thermal conductivity and viscosity are determined using spherical nanoparticle correlations.
Findings
The numerical investigations cover various parameters, including nanoparticle volume concentration, Hartmann number, Rayleigh number, heat source/sink effects and inclination angle. As the Hartmann and Rayleigh numbers increase, there is a significant enhancement in entropy generation. The average Nusselt number experiences a substantial increase at extremely high values of the Rayleigh number and inclination.
Practical implications
This numerical investigation explores advanced applications involving various combinations of influential parameters, different nanoparticles, enclosure inclinations and improved designs. The goal is to control fluid flow and enhance heat transfer rates to meet the demands of the Fourth Industrial Revolution.
Originality/value
In a 90° tilted enclosure, the addition of 5% hybrid nanoparticles to the base fluid resulted in a 17.139% increase in the heat transfer rate for Ag–MgO nanoparticles and a 16.4185% increase for Ag–TiO2 nanoparticles compared to the base fluid. It is observed that a 5% nanoparticle volume fraction results in an increased heat transfer rate, influenced by variations in both the Darcy and Rayleigh numbers. The study demonstrates that the Ag–MgO hybrid nanofluid exhibits superior heat transfer and fluid transport performance compared to the Ag–TiO2 hybrid nanofluid. The simulations pertain to the use of hybrid magnetic nanofluids in fuel cells, solar cavity receivers and the processing of electromagnetic nanomaterials in enclosed environments.
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Ali J. Chamkha, B. Mallikarjuna, R. Bhuvana Vijaya and D.R.V. Prasada Rao
The purpose of this paper is to study the effects of Soret and Dufour effects on convective heat and mass transfer flow through a porous medium in a rectangular duct in the…
Abstract
Purpose
The purpose of this paper is to study the effects of Soret and Dufour effects on convective heat and mass transfer flow through a porous medium in a rectangular duct in the presence of inclined magnetic field.
Design/methodology/approach
Using the non-dimensional variables, the governing equations have been transformed into a set of differential equations, which are non-linear and cannot be solved analytically, therefore finite element method has been used for solving the governing equations.
Findings
The influence of thermo-diffusion, diffusion thermo, radiation, dissipation, heat sources and the inclined magnetic field on all the flow, heat and mass transfer characteristics has been found to be significant.
Originality/value
The problem is relatively original as it combines many effects as Soret and Dufour effects and chemical reaction under inclined magnetic field.
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Kalidas Das and Pinaki Ranjan Duari
Several graphs, streamlines, isotherms and 3D plots are illustrated to enlighten the noteworthy fallouts of the investigation. Embedding flow factors for velocity, induced…
Abstract
Purpose
Several graphs, streamlines, isotherms and 3D plots are illustrated to enlighten the noteworthy fallouts of the investigation. Embedding flow factors for velocity, induced magnetic field and temperature have been determined using parametric analysis.
Design/methodology/approach
Ternary hybrid nanofluids has outstanding hydrothermal performance compared to classical mono nanofluids and hybrid nanofluids owing to the presence of triple tiny metallic particles. Ternary hybrid nanofluids are considered as most promising candidates in solar energy, heat exchangers, electronics cooling, automotive cooling, nuclear reactors, automobile, aerospace, biomedical devices, food processing etc. In this work, a ternary hybrid nanofluid flow that contains metallic nanoparticles over a wedge under the prevalence of solar radiating heat, induced magnetic field and the shape factor of nanoparticles is considered. A ternary hybrid nanofluid is synthesized by dispersing iron oxide (Fe3O4), silver (Ag) and magnesium oxide (MgO) nanoparticles in a water (H2O) base fluid. By employing similarity transformations, we can convert the governing equations into ordinary differential equations and then solve numerically by using the Runge–Kutta–Fehlberg approach.
Findings
There is no fund for the research work.
Social implications
This kind of study may be used to improve the performance of solar collectors, solar energy and solar cells.
Originality/value
This investigation unfolds the hydrothermal changes of radiative water-based Fe3O4-Ag-MgO-H2O ternary hybrid nanofluidic transport past a static and moving wedge in the presence of solar radiating heating and induced magnetic fields. The shape factor of nanoparticles has been considered in this study.
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John H. Merkin, Yian Yian Lok and Ioan Pop
The purpose of this study is to obtain both the numerical and asymptotic solutions of the unsteady mixed convection flow and heat transfer over an expanding or contracting…
Abstract
Purpose
The purpose of this study is to obtain both the numerical and asymptotic solutions of the unsteady mixed convection flow and heat transfer over an expanding or contracting cylinder which is placed vertically.
Design/methodology/approach
Solutions of the governing ordinary (similarity) differential equations for the fluid flow and temperature field are obtained using the function bvp4c from MATLAB. The problem involves the Prandtl number σ, the mixed convection parameter λ and unsteadiness parameter S that characterize an expanding or contracting cylinder. This solution approach is capable of producing multiple solutions once the necessary assumptions are provided.
Findings
It is found that solutions exist for all negative values of S, expanding cylinder, and only for small positive values of S, contracting cylinder. Further, more than one solution is observed; numerical computation shows that the critical point of S becomes singular as λ approaching zero. For the case of expanding cylinder, the mixed convection parameter has a significant effect on both the flow and heat transfer characteristics. Asymptotic analysis also shows that when σ is large, dual solutions exist for some values of S and λ.
Originality/value
The present results are new and original for the study of the unsteady mixed convection flow and heat transfer over an expanding/contracting cylinder where numerical solutions are obtained for representative values of the involved parameters. Asymptotic solutions for large λ and large σ are derived.
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Lakshmi Kumar, D. Malathy and L.S. Ganesh
The purpose of this paper is to understand the influence of technology change in the banking sector by employing data envelopment analysis (DEA) and also to determine the change…
Abstract
Purpose
The purpose of this paper is to understand the influence of technology change in the banking sector by employing data envelopment analysis (DEA) and also to determine the change in total factor productivity (TFP) and its components, namely technical change and technical efficiency change.
Design/methodology/approach
The DEA method has been used to assess the efficiency of the entire banking sector and the bank groups. The purpose has been to investigate TFP change and its components' (obtained using Malmquist index) influence on the growth in the banking sector as well as in the four bank groups. In doing so, for each bank group the levels of technical efficiency, technical efficiency change, efficiency change and TFP change have been estimated. Further investigation has been done to determine if significant differences in these exist between the different bank groups in terms of size, time period and ownership. The determinants of productivity have been assessed.
Findings
The TFP growth over the entire period (1995‐2006) was driven by technical change as compared to efficiency change, showing that technology and innovation had a greater impact than efficiency change, or the catch‐up effect. The fixed effects estimates of the determinants of TFP change and its components show that size, ownership and time period exert significant effect on technical change.
Practical implications
The results of the analysis presented in this paper suggest that policies that result in efficiency change are likely to have little impact on the future prospects of the banking sector relative to policies that foster the adoption of the latest technologies. This has exactly been the focus of Reserve Bank of India and though some banks may consider it as an imposition of technology, the result of this requirement appears to be positive as is apparent from this paper's analysis.
Originality/value
The value of this paper comes from the empirical testing that in the Indian banking sector growth in the more recent period came from technology change or frontier shifts as compared to efficiency change. Also, growth is larger due to frontier shifts than due to efficiency change. This endorses Lucas' findings regarding the focus on the positive impacts of deregulation and competition in the Indian banking sector.
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Shankar Reddy Kolle, M.S. Vijayashree and T.H. Shankarappa
The purpose of this paper is to reveal the bibliometric characteristics of highly cited articles in Malaria research for the period of 1991-2015.
Abstract
Purpose
The purpose of this paper is to reveal the bibliometric characteristics of highly cited articles in Malaria research for the period of 1991-2015.
Design/methodology/approach
The data of highly cited articles for the period of 1991 to 2015 were extracted from the Science Citation Index Expended of Web of Science. The keyword “Malaria” was used as topic term to search documents that contained this word in the title or keyword or abstract of the documents that published in 1991 to 2015. A total of 1,614 articles having TC2015 = 100 were retrieved as highly cited articles for further analysis, and Microsoft excel was used for the analysis purpose.
Findings
A total of 1,614 of highly cited articles were published in the 230 journals for the period of 1991 to 2015, and majority of the articles were appeared in journals that have top impact factor. The articles published in the 2011s have greater average citations and authors per article. Six journals have produced almost a quarter of highly cited articles and remaining articles were published in 224 journals. Proceedings of the National Academy of Sciences of the USA was the most productive journal with 154 articles, which accounts for 9.53 per cent of the total articles, followed by Lancet (110; 6.81 per cent). We found degree collaboration value of 0.971 for the articles, which indicates the clear dominance of multiple authors in publication of highly cited articles in Malaria research. In this study, new indictor called P index was applied for the evaluation of the author’s productivity. As per the p-value, the White, NJ has emerged as the most productive author with the p-value of 0.41 (61 articles), followed by Marsh, K (p = 0.33), Nosten, F (p = 0.32) and Snow, RW (p = 0.31). The USA and the UK were the most productive countries. The article entitled as “Global and regional burden of disease and risk factors, 2001: systematic analysis of population health data” contributed by Lopez et al. (2006) was the most cited article with 2,245 citations in 2015.
Research limitations/implications
The data for the present study was limited to the publications that indexed in Science Citation index Expended of Web of Science.
Originality/value
This paper would be useful to the researchers to know the trends and achievements in the Malaria research and also to the library and information science professionals in collection building process.