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1 – 10 of 183Sadia Rashid, Tasawar Hayat, Sumaira Qayyum, Muhammad Ayub and Ahmed Alsaedi
The purpose of this study is to study flow caused by rotating frame. Effects of Darcy–Forchheimer and porous medium are considered to study velocity field. Concentration field is…
Abstract
Purpose
The purpose of this study is to study flow caused by rotating frame. Effects of Darcy–Forchheimer and porous medium are considered to study velocity field. Concentration field is discussed in presence of activation energy. Darcy–Forchheimer in a rotating frame is examined. Flow because of stretched sheet fills the porous space. Binary chemical reaction is entertained. Resulting system is numerically solved. The plots are arranged for rotational parameter, porosity parameter, coefficients of inertia, Prandtl number and Schmidt number. It is revealed that rotation on velocity has opposite effects when compared with temperature and concentration distributions. Skin friction coefficients and local Nusselt and Sherwood numbers are numerically discussed.
Design/methodology/approach
Darcy–Forchheimer in a rotating frame is examined. Flow because of stretched sheet fills the porous space. Binary chemical reaction is entertained. Resulting system is numerically solved. The plots are arranged for rotational parameter, porosity parameter, coefficients of inertia, Prandtl number and Schmidt number. It is revealed that rotation on velocity has opposite effects when compared with temperature and concentration distributions. Skin friction coefficients and local Nusselt and Sherwood numbers are numerically discussed.
Findings
The major findings here are as follows: an addition in porosity λ causes decay in velocity f′(η) while there is opposite behavior for temperature θ(η) and concentration ϕ(η) fields. θ and ϕ via β have similar results qualitatively. There is an opposite behavior of Pr on temperature and concentration. Inverse behavior of λ on ϕ and wall mass flux is noted. Concentration ϕ is decreasing function of reaction rate constant σ. Skin friction coefficient has similar qualitative results for λ and β. Temperature gradient −θ′(0) is decreased by λ and β.
Originality/value
Here, the authors are interested to investigate rotating flow in a porous space. Dissipation and radiation effects are neglected. Effects of activation energy are studied. This work is not done yet in literature.
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Tasawar Hayat, Tayyaba Ayub, Taseer Muhammad, Ahmed Alsaedi and M. Mustafa
The purpose of this paper is to construct mathematical model for squeezed flow of carbon-water nanofluid between parallel disks considering Darcy–Forchheimer porous medium…
Abstract
Purpose
The purpose of this paper is to construct mathematical model for squeezed flow of carbon-water nanofluid between parallel disks considering Darcy–Forchheimer porous medium. Thermal conductivity of carbon nanotubes is estimated through the well-known Xue model. Such research work is not carried out in the past even in the absence of Darcy–Forchheimer porous space. Forchheimer equation is preferred here to account for both low and high velocity inertial effects. Researchers also found that dispersion of carbon nanotubes in water elevates the thermal conductivity of resulting nanofluid by 100 per cent.
Design/methodology/approach
Homotopy analysis method (HAM) is used for the convergent series solutions of the governing system.
Findings
Nusselt number at the lower disk increases when squeezing parameter Sq enlarges. This illustrates that heat transfer rate at the lower wall can be enhanced by increasing the squeezing velocity of the lower disk. The results demonstrate a decreasing trend in temperature profile for increasing volume fraction of carbon nanotubes. Moreover, improvement in heat transfer rate because of existence of carbon nanotubes is also apparent. A significant enhancement in temperature profile is depicted when inertial permeability coefficient is enhanced. Skin friction coefficients at the lower and upper disks are higher for MWCNTs in comparison to the SWCNTs.
Originality/value
To the best of author’s knowledge, no such consideration has been given in the literature yet.
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A.K. Abdul Hakeem, Priya S., Ganga Bhose and Sivasankaran Sivanandam
The purpose of this study is to provide that porous media and viscous dissipation are crucial considerations when working with hybrid nanofluids in various applications.Recent…
Abstract
Purpose
The purpose of this study is to provide that porous media and viscous dissipation are crucial considerations when working with hybrid nanofluids in various applications.Recent years have witnessed significant progress in optimizing these fluids for enhanced heat transfer within porous (Darcy–Forchheimer) structures, offering promising solutions for various industries seeking improved thermalmanagement and energy efficiency.
Design/methodology/approach
The first step is to transform the original partial differential equations into a system of first-order ordinary differential equations (ODEs). The fourth-order Runge–Kutta method is chosen for its accuracy in solving ODEs. The present study investigates the free convective boundary layer flow of hybrid nanofluids over a moving thin inclined needle with the slip flow brought about by inclined Lorentz force and Darcy–Forchheimer porous matrix, viscous dissipation.
Findings
It is found that slip conditions (velocity and Thermal) exist for a range of the natural convection boundary layer flow. In the hybrid nanofluid flow, which consists of Al2O3 and Fe3O4 are nanoparticles, H2O − C2H6O2 (50:50) are considered as the base fluid. The consequence of the governing parameter on the momentum and temperature profile distribution is graphically depicted. The range of the variables is 1 ≤ M ≤ 4, 1 ≤ d ≤ 2.5, 1 ≤ δ ≤ 4, 1 ≤ Fr ≤ 7, 1 ≤ Kr ≤ 7 and 0.5≤λ ≤ 3.5. The Nusselt number and skin friction factors are used to calculate the numerical values of various parameters, which are displayed in Table 4. These analyses elucidate that upsurges in the value of the Fr noticeably diminish the momentum and temperature. It is investigated to see if the contemporary results are in outstanding promise with the outcomes reported in earlier works.
Practical implications
The results can be very helpful to improve the energy efficiency of thermal systems.
Social implications
The hybrid nanofluids in heat transfer have the potential to improve the energy efficiency and performance of a wide range of systems.
Originality/value
This study proposes that in the combined effects of hybrid nanofluid properties, the inclined Lorentz force, the Darcy–Forchheimer model for porous media and viscous dissipation on the boundary layer flow of a conducting fluid over a moving thin inclined needle. Assessing the potential practical applications of the hybrid nanofluids in inclined needles, this could involve areas such as biomedical engineering, drug delivery systems or microfluidic devices. In future should explore the benefits and limitations of using hybrid nanofluids in these applications.
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Abstract
Purpose
In this communication, a theoretical simulation is aimed to characterize the Darcy–Forchheimer flow of a magneto-couple stress fluid over an inclined exponentially stretching sheet. Stokes’ couple stress model is deployed to simulate non-Newtonian microstructural characteristics. Two different kinds of thermal boundary conditions, namely, the prescribed exponential order surface temperature (PEST) and prescribed exponential order heat flux, are considered in the heat transfer analysis. Joule heating (Ohmic dissipation), viscous dissipation and heat source/sink impacts are also included in the energy equation because these phenomena arise frequently in magnetic materials processing.
Design/methodology/approach
The governing partial differential equations are transformed into nonlinear ordinary differential equations (ODEs) by adopting suitable similar transformations. The resulting system of nonlinear ODEs is tackled numerically by using the Runge–Kutta fourth (RK4)-order numerical integration scheme based on the shooting technique. The impacts of sundry parameters on stream function, velocity and temperature profiles are viewed with the help of graphical illustrations. For engineering interests, the physical implication of the said parameters on skin friction coefficient, Nussult number and surface temperature are discussed numerically through tables.
Findings
As a key outcome, it is noted that the augmented Chandrasekhar number, porosity parameter and Forchhemeir parameter diminish the stream function as well as the velocity profile. The behavior of the Darcian drag force is similar to the magnetic field on fluid flow. Temperature profiles are generally upsurged with the greater magnetic field, couple stress parameter and porosity parameter, and are consistently higher for the PEST case.
Practical implications
The findings obtained from this analysis can be applied in magnetic material processing, metallurgy, casting, filtration of liquid metals, gas-cleaning filtration, cooling of metallic sheets, petroleum industries, geothermal operations, boundary layer resistors in aerodynamics, etc.
Originality/value
From the literature review, it has been found that the Darcy–Forchheimer flow of a magneto-couple stress fluid over an inclined exponentially stretching surface with heat flux conditions is still scarce. The numerical data of the present results are validated with the already existing studies under limited cases and inferred to have good concord.
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Muhammad Ijaz Khan, Madiha Rashid, Tasawar Hayat, Niaz B. Khan and Ahmed Alsaedi
This paper aims to examine the three-dimensional (3D) flow of carbon nanotubes (CNTs) due to bidirectional nonlinearly stretching surface by considering porous medium…
Abstract
Purpose
This paper aims to examine the three-dimensional (3D) flow of carbon nanotubes (CNTs) due to bidirectional nonlinearly stretching surface by considering porous medium. Characteristics of both single-walled CNTs and multi-walled CNTs are discussed by considering Xue model. Darcy–Forchheimer model is used for flow saturating porous medium.
Design/methodology/approach
Optimal homotopy analysis method is used for the development of series solutions.
Findings
The authors deal with 3D Darcy–Forchheimer flow of CNTs over a nonlinearly stretching surface. Heat transport mechanism is discussed in the presence of Xue model. The homogeneous and heterogeneous effects are also accounted. The mathematical modeling is computed using boundary-layer approximations.
Originality/value
No such work has been done yet in the literature.
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T. Hayat, Arsalan Aziz, Taseer Muhammad and A. Alsaedi
The purpose of this study is to examine the Darcy–Forchheimer flow of viscous nanoliquid because of a rotating disk. Thermophoretic diffusion and random motion aspects are…
Abstract
Purpose
The purpose of this study is to examine the Darcy–Forchheimer flow of viscous nanoliquid because of a rotating disk. Thermophoretic diffusion and random motion aspects are retained. Heat and mass transfer features are analyzed through convective conditions.
Design/methodology/approach
The governing systems are solved numerically by the shooting technique.
Findings
Higher porosity parameter and Forchheimer number Fr depict similar trend for both velocity profiles f' and g. Both temperature and concentration profiles show increasing behavior for higher Forchheimer number Fr. An increase in Prandtl number Pr corresponds to lower temperature profile, while opposite trend is noticed for thermal Biot number. Larger concentration Biot number exhibits increasing behavior for both concentration and its associated layer thickness.
Originality/value
To the best of the author’s knowledge, no such consideration has been given in the literature yet.
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Tasawar Hayat, Arsalan Aziz, Taseer Muhammad and Ahmed Alsaedi
The aim of this study is to elaborate three dimensional rotating flow of nanoliquid induced by a stretchable sheet subject to Darcy–Forchheimer porous space. Thermophoretic…
Abstract
Purpose
The aim of this study is to elaborate three dimensional rotating flow of nanoliquid induced by a stretchable sheet subject to Darcy–Forchheimer porous space. Thermophoretic diffusion and random motion aspects are retained. Prescribed surface heat flux and prescribed surface mass flux conditions are implemented at stretchable surface. Convergent series solutions have been derived for velocities, temperature and concentration.
Design/methodology/approach
Optimal homotopy analysis method is implemented for the solution development.
Findings
The current solution demonstrates very good agreement with those of the previously published studies in the special cases of regular fluid and nanofluids. Graphical results are presented to investigate the influences of the titania and copper nanoparticle volume fractions and also the nodal/saddle indicative parameter on flow and heat transfer characteristics. Here, the thermal characteristics of hybrid nanofluid are found to be higher in comparison to the base fluid and fluid containing single nanoparticles, respectively. An important point to note is that the developed model can be used with great confidence to study the flow and heat transfer of hybrid nanofluids.
Originality/value
To the best of the authors’ knowledge, no such consideration has been given in the literature yet.
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Jawad Raza, Sumera Dero, Liaquat Ali Lund and Zurni Omar
The purpose of study is to examine the dual nature of the branches for the problem of Darcy–Forchheimer porous medium flow of rotating nanofluid on a linearly stretching/shrinking…
Abstract
Purpose
The purpose of study is to examine the dual nature of the branches for the problem of Darcy–Forchheimer porous medium flow of rotating nanofluid on a linearly stretching/shrinking surface under the field of magnetic influence. The dual nature of the branches confronts the uniqueness and existence theorem, moreover, mathematically it is a great achievement. For engineering purposes, this study applied a linear stability test on the multiple branches to determine which solution is physically reliable (stable).
Design/methodology/approach
Nanofluid model has been developed with the help of Buongiorno model. The partial differential equations in space coordinates for the law of conservation of mass, momentum and energy have been transformed into ordinary differential equations by introducing the similarity variables. Two numerical techniques, namely, the shooting method in Maple software and the three-stage Lobatto IIIA method in Matlab software, have been used to find multiple branches and to accomplish stability analysis, respectively.
Findings
The parametric investigation has been executed to find the multiple branches and explore the effects on skin friction, Sherwood number, Nusselt number, concentration and temperature profiles. The findings exhibited the presence of dual branches only in the case of a shrinking sheet.
Originality/value
The originality of work is a determination of multiple branches and the performance of the stability analysis of the branches. It has also been confirmed that such a study has not yet been considered in the previous literature.
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Thermal features of hybrid nanoliquid consist of Cu–Ti, CuO–TiO2 and C71500–Ti6Al4V/H2O as hybrid mixtures of nano-sized particles in a base fluid through a microchannel are…
Abstract
Purpose
Thermal features of hybrid nanoliquid consist of Cu–Ti, CuO–TiO2 and C71500–Ti6Al4V/H2O as hybrid mixtures of nano-sized particles in a base fluid through a microchannel are inspected. In this study, flow model of Darcy–Forchheimer is hired to examine the flow of hybrid composition.
Design/methodology/approach
The equations which delineate the physical occurrence of the flow are resolved via Runge–Kutta–Fehlberg scheme united through shooting procedure.
Findings
It is established that flow velocity of hybrid nano composition satisfies the identity U_(CuO-TiO2/water)>U_(Cu–Ti/water)>U_(C71500–Ti6Al4V/water).
Originality/value
Hybrid nanofluid flow of Cu–Ti, CuO–TiO2 and C71500–Ti6Al4V/H2O hybrid mixtures in a base fluid through a microchannel are inspected.
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Shashikumar N.S., Gireesha B.J., B. Mahanthesh and Prasannakumara B.C.
The microfluidics has a wide range of applications, such as micro heat exchanger, micropumps, micromixers, cooling systems for microelectronic devices, fuel cells and…
Abstract
Purpose
The microfluidics has a wide range of applications, such as micro heat exchanger, micropumps, micromixers, cooling systems for microelectronic devices, fuel cells and microturbines. However, the enhancement of thermal energy is one of the challenges in these applications. Therefore, the purpose of this paper is to enhance heat transfer in a microchannel flow by utilizing carbon nanotubes (CNTs). MHD Brinkman-Forchheimer flow in a planar microchannel with multiple slips is considered. Aspects of viscous and Joule heating are also deployed. The consequences are presented in two different carbon nanofluids.
Design/methodology/approach
The governing equations are modeled with the help of conservation equations of flow and energy under the steady-state situation. The governing equations are non-dimensionalized through dimensionless variables. The dimensionless expressions are treated via Runge-Kutta-Fehlberg-based shooting scheme. Pertinent results of velocity, skin friction coefficient, temperature and Nusselt number for assorted values of physical parameters are comprehensively discussed. Also, a closed-form solution is obtained for momentum equation for a particular case. Numerical results agree perfectly with the analytical results.
Findings
It is established that multiple slip effect is favorable for velocity and temperature fields. The velocity field of multi-walled carbon nanotubes (MWCNTs) nanofluid is lower than single-walled carbon nanotubes (SWCNTs)-nanofluid, while thermal field, Nusselt number and drag force are higher in the case of MWCNT-nanofluid than SWCNT-nanofluid. The impact of nanotubes (SWCNTs and MWCNTs) is constructive for thermal boundary layer growth.
Practical implications
This study may provide useful information to improve the thermal management of microelectromechanical systems.
Originality/value
The effects of CNTs in microchannel flow by utilizing viscous dissipation and Joule heating are first time investigated. The results for SWCNTs and MWCNTs have been compared.
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