Spectral Quasi-Linearization Method for Entropy Generation Using the Cattaneo–Christov Heat Flux Model

2019 ◽  
Vol 17 (05) ◽  
pp. 1940002
Author(s):  
Hiranmoy Mondal ◽  
Precious Sibanda

In this paper, we studying the entropy generation in Sakiadis nanofluid flowing along a moving plate subject to magnetic field and a Cattaneo–Christov heat flux model that may predict the effects of thermal relaxation time on the boundary layer flow. The nonlinear transport equations are solved using a spectral quasi-linearization method. An analysis of the convergence of the method is presented, and the importance of various fluid and physical parameters concerning the behavior of the solutions is explored. Numerical analysis of the residual error and convergence properties of the method are also discussed. One of the benefits of the proposed method is that it is computationally fast and gives very accurate results after only a few iterations using very few grid points in the numerical discretization process. It is shown that the method converges fast and gives accurate results. The results show that entropy generation increases with an increase in the Reynolds number. The Bejan number is strongly affected by variations in the magnetic parameter, Brinkman number and temperature difference parameter.

Symmetry ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 331 ◽  
Author(s):  
Zahir Shah ◽  
Asifa Tassaddiq ◽  
Saeed Islam ◽  
A.M. Alklaibi ◽  
Ilyas Khan

In this paper we investigated the 3-D Magnetohydrodynamic (MHD) rotational nanofluid flow through a stretching surface. Carbon nanotubes (SWCNTs and MWCNTs) were used as nano-sized constituents, and water was used as a base fluid. The Cattaneo–Christov heat flux model was used for heat transport phenomenon. This arrangement had remarkable visual and electronic properties, such as strong elasticity, high updraft stability, and natural durability. The heat interchanging phenomenon was affected by updraft emission. The effects of nanoparticles such as Brownian motion and thermophoresis were also included in the study. By considering the conservation of mass, motion quantity, heat transfer, and nanoparticles concentration the whole phenomenon was modeled. The modeled equations were highly non-linear and were solved using homotopy analysis method (HAM). The effects of different parameters are described in tables and their impact on different state variables are displayed in graphs. Physical quantities like Sherwood number, Nusselt number, and skin friction are presented through tables with the variations of different physical parameters.


2018 ◽  
Vol 388 ◽  
pp. 146-157 ◽  
Author(s):  
K. Gangadhar ◽  
Chintalapudi Suresh Kumar ◽  
S. Mohammed Ibrahim ◽  
Giulio Lorenzini

The study observes the flow and heat transfer in upper-convected Maxwell fluid over a rapidly stretching surface with viscous dissipation. Cattaneo-Christov heat flux model has been used in the preparation of the energy equation. The model is used in guessing the impacts of thermal relaxation time over boundary layer. Similarity method has been used to keep normal the supervising boundary layer equations. Local similarity solutions have been obtained through spectral relaxation method. The fluid temperature has a relation with thermal relaxation time inversely and our calculations have shown the same.. In addition the fluid velocity is a receding activity of the fluid relaxation time. A comparative study of Fourier’s law and the Cattaneo-Christov’s law has been done and inserted in this.


Author(s):  
B Vasu ◽  
Atul Kumar Ray ◽  
Rama SR Gorla

Free convection flow of Jeffrey nanofluid past a vertical plate with sinusoidal variations of surface temperature and species concentration is presented. The study of heat transfer and nanofluid transport has been done by employing Cattaneo–Christov heat flux model and Buongiorno model, respectively. Equations governing the flow are non-dimensionalized using appropriate transformations. Furthermore, the method of local similarity and local non-similarity is used to reduce the equations into non-linear coupled system of equations which are then solved by homotopy analysis method. The obtained results are validated by comparing with the existing results available in the literature. The numerical results are found to be in good agreement. The effects of varying the physical parameters such as Deborah Number, Prandtl number, Schmidt number, thermophoresis parameter, Brownian motion parameter and buoyancy ratio parameter are obtained and presented graphically. The effect of sinusoidal variation of surface temperature and species concentration on the skin friction coefficient, Nusselt number and Sherwood number is also shown. Velocity for Jeffrey nanofluid is more than the Newtonian nanofluid while temperature and nanoparticle concentration for Jeffrey nanofluid is less than the Newtonian nanofluid. Raising value of thermal relaxation times leads to an increase in the heat transfer coefficient. It is observed that temperature of Cattaneo–Christov heat flux model is less than that in classical Fourier’s model away from the vertical wall. These types of boundary layer flow problems are found in vertical film solar energy collector, grain storage, transportation and power generation, thermal insulation, gas production, petroleum resources, geothermal reservoirs.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Muhammad Naveed ◽  
Muhammad Imran ◽  
Zaheer Abbas

Abstract This paper aims to investigate the transfer of heat phenomenon in a hydromagnetic time dependent flow of micropolar fluid across an oscillating stretchable curved surface by using the Cattaneo–Christov heat flux model, which considers thermal relaxation time. An elastic curved surface that stretches back and forth causes the flow situation. The flow equations are derived as nonlinear partial differential equations by incorporating a curvilinear coordinates system, which is then solved analytically via the homotopy analysis method (HAM). The accuracy of the derived analytical results is also examined by using a finite-difference technique known as the Keller box method, and it is found to be in strong agreement. The influences of various physical characteristics such as material parameter, magnetic parameter, thermal relaxation parameter, a dimensionless radius of curvature, Prandtl number and ratio of surface’s oscillating frequency to its stretching rate parameter on angular velocity, fluid velocity, pressure, temperature, heat transmission rate, and skin friction and couple stress coefficient are depicted in detail with the help of graphs and tables. Furthermore, for the verification and validation of the current results, a tabular comparison of the published data in the literature for the case of flat oscillating surface versus curved oscillating surface is carried out and found to be in good agreement.


Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 395 ◽  
Author(s):  
Liaqat Ali ◽  
Xiaomin Liu ◽  
Bagh Ali

In this mathematical study, magnetohydrodynamic, time-independent nanofluid flow over a stretching sheet by using the Cattaneo–Christov heat flux model is inspected. The impact of the thermal, solutal boundary and gravitational body forces with the effect of double stratification on the mass flow and heat transfer phenomena is also observed. The temperature-dependent viscosity impact on heat transfer through a moving sheet with capricious heat generation in nanofluids have studied, and the viscosity of the fluid is presumed to deviate as the inverse function of temperature. With the appropriate transformations, the system of partial differential equations is transformed into a system of nonlinear ordinary differential equations. By applying the variational finite element method, the transformed system of equations is solved. The properties of the several parameters for buoyancy, velocity, temperature, stratification, and Brownian motion parameters have examined. The enhancement in the concentration and thermal boundary layer thickness of the nanofluid sheet due to the increment in the viscosity parameter, also increased the temperature and concentration of nanoparticles. Moreover, the fluid temperature declined with the increasing values of thermal relaxation parameter. This displays that the Cattaneo–Christov heat flux model provides a better assessment of temperature distribution. Moreover, confirmation of the code and precision of the numerical method has inveterate with the valuation of the presented results with previous studies.


Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 610
Author(s):  
Muhammad Wakeel Ahmad ◽  
Luthais B. McCash ◽  
Zahir Shah ◽  
Rashid Nawaz

The second grade nanofluid flow with Cattaneo-Christov heat flux model by a stretching disk is examined in this paper. The nanofluid flow is characterized with Hall current, Brownian motion and thermophoresis influences. Entropy optimization with nonlinear thermal radiation, Joule heating and heat absorption/generation is also presented. The convergence of an analytical approach (HAM) is shown. Variation in the nanofluid flow profiles (velocities, thermal, concentration, total entropy, Bejan number) via influential parameters and number are also presented. Radial velocity, axial velocity and total entropy are enhanced with the Weissenberg number. Axial velocity, tangential velocity and Bejan number are heightened with the Hall parameter. The total entropy profile is enhanced with the Brinkman number, diffusion parameter, magnetic parameter and temperature difference. The Bejan number profile is heightened with the diffusion parameter and temperature difference. Arithmetical values of physical quantities are illustrated in Tables.


2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
Zeeshan Khan ◽  
Haroon Ur Rasheed ◽  
Sahib Noor ◽  
Waris Khan ◽  
Qayyum Shah ◽  
...  

This paper provides a substantial amount of study related to coupled fluid flow and heat conduction of an upper-convected-Maxwell viscoelastic liquid over a stretching plane with slip velocity. A new model, presented by Christov, for thermal convection is employed. The partial differential equations are converted to ordinary differential equations by using appropriate transformation variables. The transformed equations are solved analytically by using the Galerkin method. For the sake of soundness, a comparison is done with a numerical method, and good agreement is found. The impacts of various parameters like slip coefficient, elasticity number, the thermal relaxation time of heat flow, and the Prandtl number over the temperature and velocity fields are studied. Furthermore, the Cattaneo–Christov heat flux model is compared with Fourier’s law. Additionally, the present results are also verified by associating with the published work as a limiting case.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Saima Batool ◽  
Muhammad Nawaz ◽  
Mohammed Kbiri Alaoui

PurposeThis study presents a mathematical approach and model that can be useful to investigate the thermal performance of fluids with microstructures via hybrid nanoparticles in conventional fluid. It has been found from the extensive literature survey that no study has been conducted to investigate buoyancy effects on the flow of Maxwell fluid comprised of hybrid microstructures and heat generation aspects through the non-Fourier heat flux model.Design/methodology/approachNon-Fourier heat flux model and non-Newtonian stress–strain rheology with momentum and thermal relaxation phenomena are used to model the transport of heat and momentum in viscoelastic fluid over convectively heated surface. The role of suspension of mono and hybrid nanostructures on an increase in the thermal efficiency of fluid is being used as a medium for transportation of heat energy. The governing mathematical problems with thermo-physical correlations are solved via shooting method.FindingsIt is noted from the simulations that rate of heat transfer is much faster in hybrid nanofluid as compare to simple nanofluid with the increasing heat-generation coefficient. Additionally, an increment in the thermal relaxation time leads to decrement in the reduced skin friction coefficient; however, strong behavior of Nusselt number is shown when thermal relaxation time becomes larger for hybrid nanofluid as well as simple nanofluid.Originality/valueAccording to the literature survey, no investigation has been made on buoyancy effects of Maxwell fluid flow with hybrid microstructures and heat generation aspects through non-Fourier heat flux model. The authors confirm that this work is original, and it has neither been published elsewhere nor is it currently under consideration for publication elsewhere.


2020 ◽  
Vol 10 (3) ◽  
pp. 886 ◽  
Author(s):  
Umair Khan ◽  
Shafiq Ahmad ◽  
Arsalan Hayyat ◽  
Ilyas Khan ◽  
Kottakkaran Sooppy Nisar ◽  
...  

In this article, the boundary layer flow of a viscous nanofluid induced by an exponentially stretching surface embedded in a permeable medium with the Cattaneo–Christov heat flux model (CCHFM) is scrutinized. We took three distinct kinds of nanoparticles, such as alumina (Al2O3), titania (TiO2) and copper (Cu) with pure water as the base fluid. The features of the heat transfer mechanism, as well as the influence of the relaxation parameter on the present viscous nanofluid flow are discussed here thoroughly. The thermal stratification is taken in this phenomenon. First of all, the problem is simplified mathematically by utilizing feasible similarity transformations and then solved analytically through the OHAM (optimal homotopy analysis method) to get accurate analytical solutions. The change in temperature distribution and axial velocity for the selected values of the specific parameters has been graphically portrayed in figures. An important fact is observed when the thermal relaxation parameter (TRP) is increased progressively. Graphically, it is found that an intensification in this parameter results in the exhaustion of the fluid temperature together with an enhancement in the heat transfer rate. A comparative discussion is also done over the Fourier’s law and Cattaneo–Christov model of heat.


2018 ◽  
Vol 388 ◽  
pp. 61-76 ◽  
Author(s):  
G. Vinod Kumar ◽  
S. Vijaya Kumar Varma ◽  
R.V.M.S.S. Kiran Kumar

The present investigation has put a focus on the hydromagnetic boundary layer unsteady flow of a nanofluid over a stretching sheet. A new heat flux model named Cattaneo-Christov is applied as the substitution of classical Fourier’s law. Buongiorno’s model is incorporated. The coupled non-linear transformed equations are solved numerically by using shooting technique with MATLAB bvp4c package. The obtained results are presented and discussed through graphs and tables in detail. Our results reveal that the unsteady parameter reduces all the three boundary layer thickness. The thermal relaxation parameter exhibits a non-conducting nature that makes the decline in fluid temperature.


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