Browse Items (11810 total)
Sort by:
-
Heat transport of magnetized Newtonian nanoliquids in an annular space between porous vertical cylinders with discrete heat source
A numerical study of MHD natural convection in an upright porous cylindrical annulus filled with magnetized nanomaterial is made by using the specificity of nanoliquids to improve the phenomenon of heat transport. The upper and lower walls are thermally insulated, whereas the outer wall is kept at a lesser temperature. The finite volume method is used to treat the governing equations via computer code with Fortran programming. The results obtained are given for the values of the Rayleigh number between 103 and 106, aspect ratio Ar = 2, radii ratio ? = 2, Hartmann number (0 ? Ha ? 80), Darcy number (10?5 ? Da ? 10?2), porosity ratio (0.1 ? ? ?0.9), and the nanoparticles volume fraction (0 ? ? ? 0.1). The transferred thermal flux, in laminar natural convection, increases with the growth of the nanoparticle concentration, the Darcy number, the porosity, the Rayleigh number and, the length of the source. 2020 Elsevier Ltd -
Heat transport of hybrid nanomaterial in an annulus with quadratic Boussinesq approximation
The convective heat transfer of hybrid nanoliquids within a concentric annulus has wide engineering applications such as chemical industries, solar collectors, gas turbines, heat exchangers, nuclear reactors, and electronic component cooling due to their high heat transport rate. Hence, in this study, the characteristics of the heat transport mechanism in an annulus filled with the Ag-MgO/H2O hybrid nanoliquid under the influence of quadratic thermal radiation and quadratic convection are analyzed. The non-uniform heat source/sink and induced magnetic field mechanisms are used to govern the basic equations concerning the transport of the composite nanoliquid. The dependency of the Nusselt number on the effective parameters (thermal radiation, nonlinear convection, and temperature-dependent heat source/sink parameter) is examined through sensitivity analyses based on the response surface methodology (RSM) and the face-centered central composite design (CCD). The heat transport of the composite nanoliquid for the space-related heat source/sink is observed to be higher than that for the temperature-related heat source/sink. The mechanisms of quadratic convection and quadratic thermal radiation are favorable for the momentum of the nanoliquid. The heat transport rate is more sensitive towards quadratic thermal radiation. 2021, Shanghai University and Springer-Verlag GmbH Germany, part of Springer Nature. -
Heat transport in the flow of magnetized nanofluid over a stretchable surface with heat sources: A mathematical model with realistic conditions
Analyzing the heat transport of nanofluids is of prime importance to various industrial and engineering sectors which involves modeling the physical phenomena via highly nonlinear partial differential equations. In this study, the flow and heat transport of a nanoliquid on a bi-directionally elongating surface subject to two different heat modulations (linear temperature-related heat source and space-related exponential heat source) is investigated using the two-component Buongiorno nanoliquid model. The dynamics of the nanoliquid are altered by an external magnetic field applied perpendicular to the sheet. The impact of Brownian motion, Lorentz forces, and thermophoresis are analyzed under the realistic passive control of the nanoparticles. A comparative analysis of the flow over the linear and nonlinear drawn surface is presented. Numeric solutions for the governing partial differential system are obtained through the finite difference method (FDM). Among two types of heat source modulations, the maximum heat transport is observed in the presence of the exponential space-based heat source modulation. The flow and thermal fields are found to advance in the linear elongated surface flow than the nonlinear elongated flow. Furthermore, the random movement of the nanoparticles and the greater magnitude of the Lorentz force have a positive effect on the thermal enhancement in the nanoliquid system. The results of the study have applications in heating/cooling processes, nanoliquid-dependent structures, and thermal systems with stretchable materials. 2021 Wiley-VCH GmbH -
Heat transport and stagnation-point flow of magnetized nanoliquid with variable thermal conductivity, Brownian moment, and thermophoresis aspects
The improvement of heat transport is a very important phenomenon in nuclear reactors, solar collectors, heat exchangers, and coolers, which can be achieved by choosing the nanofluid as the functional fluid. Nanofluids improve thermophysical properties; as a result, they have made great progress in engineering, biomedical, and industrial applications. Therefore, a numerical study has been proposed to analyze the flow and heat transport of nanoliquids over an extendable surface near a stagnation point with variable thermal conductivity under the influence of the magnetic field, due to their importance in the engineering field. Nanoliquid attributes explain the Brownian motion and the diffusion of thermophoresis. The effects of the chemical reaction and the uniform internal heat source/heat sink are also considered. The Nachtsheim-Swigert shooting procedure based on the Runge-Kutta scheme is used for numerical calculation. The impact of effective parameters on velocity, temperature, and volume fraction of the nanoparticles is shown in the graphs and reported in detail. The surface criteria are also estimated with respect to the shear stress and the rate of heat and mass transfer. The aspects of the Brownian moment and Lorentz force are positively correlated to the thermal field of the nanoliquid. Also, the variable thermal conductivity aspect favors the growth of the thermal boundary layer. 2020 Wiley Periodicals LLC -
Heat transfer simulation of reline flowing in an elliptic shaped duct: A deep eutectic solvent
Deep Eutectic solvents have emerged as promising alternatives to conventional solvents due to their unique properties and applications. The flow of deep eutectic solvents in various industrial processes has garnered significant attention due to their versatile applications in fields ranging from chemical engineering to energy storage. This study presents a comprehensive mathematical model aimed at elucidating the intricate behavior of eutectic solvent flow within an elliptic duct, a geometric configuration relevant to many real-world systems. In this article, the deep eutectic solvent is composed of choline chlorideurea and is also called Reline. The proposed mathematical model accounts for the complex interplay of fluid dynamics, thermodynamics, and elliptic duct geometry. Key components of the model include the Navier-Stokes equations, which describe the fluid flow, coupled with heat transfer equations to account for temperature variations within the system. The model also considers the phase change behavior of the eutectic solvent, which may exhibit solidification or crystallization phenomena under certain conditions. Numerical simulations and analytical solutions are employed to investigate various aspects of eutectic solvent flow within elliptic ducts, such as velocity profiles, pressure distributions, temperature gradients, and phase transition phenomena. The study explores the influence of key parameters, including the Reynolds number, the aspect ratio of the duct, and the thermophysical properties of the eutectic solvent, on the systems behavior. From the results, it was clearly observed that the velocity at the narrow region decreased as the pressure raised and the Reynolds number profile indicated the presence of turbulent flow behavior. 2024 Taylor & Francis Group, LLC. -
Heat transfer optimization of hybrid nanomaterial using modified Buongiorno model: A sensitivity analysis
Sensitivity analysis of the heat transfer rate in the flow of the hybrid nanoliquid C2H6O2?H2O (base liquid) +MoS2?Ag (nanoparticles) over a wedge using the Response Surface Methodology (RSM) is carried out. The nanomaterial is modeled using the modified Buongiorno nanofluid model (MBNM) that considers the major slip mechanisms and the effective properties of the hybrid nanoliquid. Two distinct heat sources- linear thermal heat source and an exponential space-dependent heat source are taken into account. The governing nonlinear two-point boundary-layer flow problem is treated numerically. The effects of pertinent parameters on the flow fields in the boundary layer region are represented graphically with suitable physical interpretations. The exponential heat source and slip mechanisms are used to study the sensitivities of the heat transfer rate. Both heat source mechanisms lead to an improvement in the temperature profile, in which the effect of the exponential space-related heat source is predominant. The Brownian motion parameter was found to be the most sensitive to the heat transfer rate. 2021 -
Heat transfer optimization and sensitivity analysis of Marangoni convection in nanoliquid with nanoparticle interfacial layer and cross-diffusion effects
Heat and mass transfer induced by Marangoni forces occur frequently in crystal growth and heat pipes, especially in microgravity situations. Therefore, the heat and mass transfer optimization in the thermosolutal Marangoni boundary layer flow of a nanomaterial with cross-diffusion effects is carried out in this study. Thermal radiation, magnetic field, and cross-diffusion are also incorporated in the thermal phenomena. The flow fields with nanolayer and without it are compared. The nanoparticle interfacial layer aspect accounted for in the nanofluid model makes the modeling more realistic. The optimization procedure is based on the Response Surface Methodology (RSM) model that utilizes the face-centered Central Composite Design (fc-CCD). The external constraining factors of the system like thermal radiation, magnetic field, and nanoparticle loading are explored for interactive impacts. The sensitivity of the heat and mass transfer is scrutinized. The interfacial layer aspect leads to an enhanced magnitude of the temperature field whereas the effect on the concentration profile is negligible. The inclination of the magnetic field augments the flow profiles significantly. The highest sensitivity of the heat and mass transfer is towards the thermal radiation aspect. The optimized output of heat and transfer rate is estimated to be when R = 1.6639, M = 1, and ? = 1 %. 2021 Elsevier Ltd -
Heat transfer optimisation through viscous ternary nanofluid flow over a stretching/shrinking thin needle
The current investigation interprets the flow and the thermal characteristics of the ternary nanofluid composed of MoS 2, ZnO, and SiO 2 spherical nanoparticles and water. The resulting nanofluid is (Formula presented.) where (Formula presented.) act as the base fluid which help in the flow and the nanoparticles contribute to enhancing the heat conductivity. The flow is assumed to occur across a thin needle whose surface is maintained at a higher temperature than the surroundings. The mathematical model is framed by incorporating radiation introduced by Rosseland in terms of partial differential equations (PDE). This system of equations governs the flow and thermal properties of fluid which are converted to a system of ordinary differential equations (ODE). The major outcomes of the study indicated that the increase in the amount of molybdenum disulfide enhanced the heat conducted by the nanofluid whereas it reduced the flow speed. The positive values of the heat source/sink parameter caused the heat conduction of the nanofluid to go high. 2023 The Author(s). Published with license by Taylor & Francis Group, LLC. -
Heat transfer of nanomaterial over an infinite disk with marangoni convection: A modified fouriers heat flux model for solar thermal system applications
The demand for energy due to the population boom, together with the harmful consequences of fossil fuels, makes it essential to explore renewable thermal energy. Solar Thermal Systems (STSs) are important alternatives to conventional fossil fuels, owing to their ability to convert solar thermal energy into heat and electricity. However, improving the efficiency of solar thermal systems is the biggest challenge for researchers. Nanomaterial is an effective technique for improving the efficiency of STSs by using nanomaterials as working fluids. Therefore, the present theoretical study aims to explore the thermal energy characteristics of the flow of nanomaterials generated by the surface gradient (Marangoni convection) on a disk surface subjected to two different thermal energy modulations. Instead of the conventional Fourier heat flux law to examine heat transfer characteristics, the CattaneoChristov heat flux (Fouriers heat flux model) law is accounted for. The inhomogeneous nanomaterial model is used in mathematical modeling. The exponential form of thermal energy modulations is incorporated. The finite?difference technique along with Richardson extrapolation is used to treat the governing problem. The effects of the key parameters on flow distributions were analyzed in detail. Numerical calculations were performed to obtain correlations giving the reduced Nusselt number and the reduced Sherwood number in terms of relevant key parameters. The heat transfer rate of solar collectors increases due to the Marangoni convection. The thermophoresis phenomenon and chaotic movement of nanoparticles in a working fluid of solar collectors enhance the temperature distribution of the system. Furthermore, the thermal field is enhanced due to the thermal energy modulations. The results find applications in solar thermal exchanger manufacturing processes. 2021 by the authors. Licensee MDPI, Basel, Switzerland. -
Heat transfer in the flow of blood-gold Carreau nanofluid induced by partial slip and buoyancy
Dynamics of blood containing gold nanoparticles on a syringe and other objects with a nonuniform thickness is of importance to experts in the industry. This study presents the significance of partial slip (i.e. combination of linear stretching and velocity gradient) and buoyancy on the boundary layer flow of blood-gold Carreau nanofluid over an upper horizontal surface of a paraboloid of revolution (uhspr). In this report, the viscosity of the Carreau fluid corresponding to an infinite shear-rate is assumed as zero, meanwhile, the viscosity corresponding to zero shear-rate, density, thermal conductivity, and heat capacity were assumed to vary with the volume fraction of nanoparticles. The governing equation that models the transport phenomenon were non-dimensionalized and parameterized using suitable similarity variables and solved numerically using classical RungeKutta method with shooting techniques and MATLAB bvp4c package for validation. The results show that temperature distribution across the flow decreases more significantly with buoyancy-related parameter when the influence of partial slip was maximized. Maximum velocity of the flow is ascertained at larger values of partial slip and buoyancy parameters. At smaller values of Deborah number and large values of volume fraction, maximum local skin friction coefficient, and local heat transfer rate are ascertained. 2018 Wiley Periodicals, Inc. -
Heat transfer in a dissipative nanofluid passing by a convective stretching/shrinking cylinder near the stagnation point
This contemporary article examines the transfer of heat properties and the flow behavior of water-based nanofluid suspended with silver nanoparticles. These silver nanoparticles have a very huge thermal conductivity and hence it is presumed that the resulting nanofluid shall have enhanced thermal conductance. This article is more focused on the study of (Formula presented.) nanofluid flowing past a cylinder that is modeled mathematically using the cylindrical coordinate system. The initial modeling is designed using a system of partial derivatives while at a later stage, this system is transformed into a nonlinear group of ordinary differential equations (ODEs). The equations in this system are solved to obtain the dual solutions by implementing the RKF-45 method which has a greater rate of convergence and additionally, it is computationally very effective. The findings of the study are dealt by plotting graphs and the discussions are based on the appearance of graphs. It is further noticed that the critical point (Formula presented.) remains constant at (Formula presented.) for any changes made in the values of heat generation/absorption coefficient. Similarly, the critical value remains constant at (Formula presented.) for any change made in the values of the Eckert number. Meanwhile, it is also observed that the increase in the Eckert number increases the temperature absorbed by the nanofluid whereas it decreases the Nusselt number. Furthermore, the higher values of the velocity slip reduce the skin friction coefficient. 2023 Wiley-VCH GmbH. -
Heat transfer enhancement using temperature-dependent effective properties of alumina-water nanoliquid with thermo-solutal Marangoni convection: A sensitivity analysis
The sensitivity of the heat transport rate in the thermo-solutal Marangoni convection of Al 2O 3- H 2O nanoliquid at 300K is analyzed. The nanoliquid is modeled using the modified Buongiorno model which incorporates the Brownian motion, effective nanoliquid properties, and thermophoresis effects. The thermophysical models proposed by Khanafer and Vafai are chosen in this analysis as these correlations are in good agreement with the experimental values. External constraining factors like thermal radiation and variable magnetic field are also considered. The basic equations are solved using apposite transformation variables and Finite Difference Method (FDM). The impacts of the effectual parameters on all the profiles are analyzed. Furthermore, the heat transport is analyzed by executing a Response Surface Methodology (RSM) model with the Brownian motion parameter (0.1 ? Nb ? 0.5), thermophoretic parameter (0.1 ? Nt ? 0.5), and nanoparticle volume fraction (1 % ? ?? 3 %). The modified Buongiorno model yields lower temperature and concentration profiles when compared to the conventional Buongiorno model. The heat transfer rate is the most sensitive to the Brownian motion parameter than thermophoresis and nanoparticle (NP) volume fraction parameters. The results of this study would be instrumental in improving the efficiency of the welding process, crystal growth, and coating technologies. 2021, King Abdulaziz City for Science and Technology. -
Heat transfer enhancement in the boundary layer flow of hybrid nanofluids due to variable viscosity and natural convection
The aim of the current work is to explore how heat transfer can be enhanced by variations in the basic properties of fluids in the presence of free convection with the aid of suspended hybrid nanofluids. Also, the influence of the Laurentz force on the flow is considered. The mathematical equations are converted into a pair of self-similarity equations by applying appropriate transformations. The reduced similarity equivalences are then solved numerically by Runge-Kutta-Fehlberg 45 th -order method. To gain better perception of the problem, the flow and energy transfer characteristics are explored for distinct values of significant factors such as variable viscosity, convection, magnetic field, and volume fraction. The results acquired are in good agreement with previously published results. The noteworthy finding is that the thermal conductivity is greater in hybrid nanofluid than that of a regular nanofluid in the presence of specified factors. The boundary layer thickness of both hybrid nanofluid and normal nanofluid diminishes due to decrease in variable viscosity. The fluid flow and temperature of the hybrid nanofluid and normal nanofluid increases as there is a rise in volume fraction. 2019 -
Heat transfer enhancement due to nanoparticles, magnetic field, thermal and exponential space-dependent heat source aspects in nanoliquid flow past a stretchable spinning disk
This study explores the heat transfer characteristics of nanoliquid flowing over a rotating disk in the presence of the applied magnetic field and convective boundary condition. The nanoliquid is flowing due to the rotation of the disk with uniform stretching of a disk along the radial direction. Effects of ESHS (exponential space-related heat source) and THS (thermal-related heat source) are the focal concern of this article. The effective thermal conductivity of ethylene glycol (EG)-based graphene oxide (GO) nanoliquid is estimated by using Nans model whereas effective dynamic viscosity is calculated through Brinkman model. The partial differential system which governed the problem is transformed by using Von-Karman stretching transformations to the ordinary differential system. The subsequent two-point ODBVP (ordinary differential boundary value problem) is treated numerically. The consequence of effective parameters of the problem on different flow fields is illustrated graphically. The numerical values of shear stress and heat transfer rate (Nusselt number) are also calculated. Further, the slope of the data points is determined to quantify the outcome. Validation of the present results is made by direct comparison with the available results and an excellent agreement is found. It is found that the rate of heat transfer increased with nanoparticle volume fraction at the rate 0.4153 and the friction factor increased by increasing nanoparticle volume fraction at the rate 3.0681. The fluctuation rate of Nusselt number due to the variation of the ESHS parameter is almost three times more than that of THS parameter. 2020, Akadiai Kiad Budapest, Hungary. -
Heat transfer and entropy generation analysis of non-Newtonian fluid flow through vertical microchannel with convective boundary condition
The entropy generation and heat transfer characteristics of magnetohydro-dynamic (MHD) third-grade fluid flow through a vertical porous microchannel with a convective boundary condition are analyzed. Entropy generation due to flow of MHD non-Newtonian third-grade fluid within a microchannel and temperature-dependent viscosity is studied using the entropy generation rate and Vogels model. The equations describing flow and heat transport along with boundary conditions are first made di-mensionless using proper non-dimensional transformations and then solved numerically via the finite element method (FEM). An appropriate comparison is made with the pre-viously published results in the literature as a limiting case of the considered problem. The comparison confirms excellent agreement. The effects of the Grashof number, the Hartmann number, the Biot number, the exponential space-and thermal-dependent heat source (ESHS/THS) parameters, and the viscous dissipation parameter on the temperature and velocity are studied and presented graphically. The entropy generation and the Bejan number are also calculated. From the comprehensive parametric study, it is recognized that the production of entropy can be improved with convective heating and viscous dissipation aspects. It is also found that the ESHS aspect dominates the THS aspect. Shanghai University and Springer-Verlag GmbH Germany, part of Springer Nature 2019. -
Heat Convection in a Viscoelastic Nanofluid Flow: A Memory DescriptiveModel
Modeling of physical phenomena with fractional differential equations is as old as modeling with ordinary differential equations. There are two stages in modeling of a memory process. One of them is short with persistent impact and other is usually governed by fractional mathematical model. It is established that fractional models fit the experimental data for the memory phenomena in better way when compared with the ordinary models, particularly in mechanics, psychology and in biology. Fractional model of viscoelastic nanofluid flow through permeable medium is studied in this communication. Convection parameters in the flow domain are used to account for buoyancy forces. The governing flow equations are computed using a numerical algorithm that combines finite difference and finite element techniques. The governing models friction coefficient, Sherwood numbers, and Nusselt numbers are calculated. Change in noninteger numbers behave similarly in concentration, temperature, and velocity fields, according to simulations. It is also noted that heat flux, ?1 and mass flux, ?2 numbers have contradictory effects on friction coefficient. Various flow patterns, particularly in the polymer industry and electrospinning for nanofiber manufacture, can be addressed in a similar manner 2023 L&H Scientific Publishing, LLC. All rights reserved -
Heat and Mass Transport in Casson Nanofluid Flow over a 3-D Riga Plate with Cattaneo-Christov Double Flux: A Computational Modeling through Analytical Method
This work examines the non-Newtonian Cassonnanofluids three-dimensional flow and heat and mass transmission properties over a Riga plate. The Buongiorno nanofluid model, which is included in the present model, includes thermo-migration and random movement of nanoparticles. It also took into account the CattaneoChristov double flux processes in the mass and heat equations. The non-Newtonian Casson fluid model and the boundary layer approximation are included in the modeling of nonlinear partial differential systems. The homotopy technique was used to analytically solve the systems governing equations. To examine the impact of dimensionless parameters on velocities, concentrations, temperatures, local Nusselt number, skin friction, and local Sherwood number, a parametric analysis was carried out. The velocity profile is augmented in this study as the size of the modified Hartmann number increases. The greater thermal radiative enhances the heat transport rate. When the mass relaxation parameter is used, the mass flux values start to decrease. 2023 by the authors. -
Heat and mass transfer of triple diffusive convection in viscoelastic liquids under internal heat source modulations
The influence of sinusoidal (trigonometric cosine [TC]) and nonsinusoidal waveforms (square, sawtooth, and triangular) of internal heat source modulation on triple diffusive convection in viscoelastic liquids is investigated. An Oldroyd-B type model is taken into account for viscoelastic liquids. Nonlinear analysis is carried out using a truncated representation of the Fourier series. To analyze the heat and mass transfer over a triply diffusive liquid layer, expressions for average Nusselt and average Sherwood numbers are derived using 8-mode generalized Lorenz equations. The transient behavior of Nusselt and Sherwood numbers is analyzed on different parameters of the problem. From the results, it is found that the internal heat source enhances the heat transfer and diminishes the mass transfer while the heat sink diminishes the heat transfer and enhances the mass transfer. The results for respective waveforms are obtained for each parameter and it is found that the maximum heat and mass transfer occurs due to TC waveform. The limiting cases of viscoelastic liquids (Newtonian, Oldroyd-B, Maxwell, and RivlinEricksen) have been tabulated and corresponding results for each of the waveforms onheat and mass transfer have been shown. 2021 Wiley Periodicals LLC -
Heat and mass transfer of triple diffusive convection in boussinesq-stokes suspension using ginzburg-landau model
The nonlinear stability of triple diffusive convection in Boussinesq-Stokes suspension is analysed by using Ginzburg-Landau model. Using the Bernoulli equation obtained from Ginzburg-Landau model, Nusselt number and Sherwood numbers of different solutes are studied to quantify the heat and mass transfer. It is found that the effect of couple stress parameter is to stabilize the system. 2017 Pushpa Publishing House, Allahabad, India. -
Heat and mass transfer of AgH2O nano-thin film flowing over a porous medium: A modified Buongiorno's model
Due to their numerous applications, such as fibre and wire coating, polymer preparation, etc., thin films have recently come into focus in the analysis of heat and mass transport. As a result, the current article's main objective is to investigate how heat and mass are transferred when an AgH2O (sliverwater) thin film flows past a stretching sheet that is subject to thermal and velocity slips. The research takes into account other variables including porosity, thermal radiation, thermophoresis, and Brownian motion, among others, to ensure that the outcomes are consistent with real-world conditions. Along with these parameters, the impact of the nanoparticle volume fraction is also analysed by incorporating the modified model of the existing Buongiorno model. The resulting mathematical model is transformed into ordinary differential equations with the help of appropriate similarity transformation. The system of equations thus obtained is solved by employing the RKF-45 technique and the outcomes are expressed in terms of graphs and tables. The major outcomes indicate that the increase in the mixed convection parameter causes enhancement in the temperature profile while a reduction in the velocity profile. The thermophoresis is found to increase both the temperature and concentration profiles of the thin film. Whereas, the greater values of the volume fraction of the nanoparticles enhance the temperature and diminishes the velocity. 2023 The Physical Society of the Republic of China (Taiwan)