scholarly journals Impact of autocatalytic chemical reaction in an Ostwald-de-Waele nanofluid flow past a rotating disk with heterogeneous catalysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bai Yu ◽  
Muhammad Ramzan ◽  
Saima Riasat ◽  
Seifedine Kadry ◽  
Yu-Ming Chu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Differential Equations ◽  
Chemical Reaction ◽  
Power Law ◽  
Variable Thickness ◽  
Rotating Disk ◽  
Thermal Profile ◽  
Nanofluid Flow ◽  
Power Law Index

AbstractThe nanofluids owing to their alluring attributes like enhanced thermal conductivity and better heat transfer characteristics have a vast variety of applications ranging from space technology to nuclear reactors etc. The present study highlights the Ostwald-de-Waele nanofluid flow past a rotating disk of variable thickness in a porous medium with a melting heat transfer phenomenon. The surface catalyzed reaction is added to the homogeneous-heterogeneous reaction that triggers the rate of the chemical reaction. The added feature of the variable thermal conductivity and the viscosity instead of their constant values also boosts the novelty of the undertaken problem. The modeled problem is erected in the form of a system of partial differential equations. Engaging similarity transformation, the set of ordinary differential equations are obtained. The coupled equations are numerically solved by using the bvp4c built-in MATLAB function. The drag coefficient and Nusselt number are plotted for arising parameters. The results revealed that increasing surface catalyzed parameter causes a decline in thermal profile more efficiently. Further, the power-law index is more influential than the variable thickness disk index. The numerical results show that variations in dimensionless thickness coefficient do not make any effect. However, increasing power-law index causing an upsurge in radial, axial, tangential, velocities, and thermal profile.

MHD Flow of Shear-Thinning Fluid over a Rotating Disk with Heat Transfer

2011 ◽  
Vol 130-134 ◽  
pp. 3599-3602
Author(s):  
Chun Ying Ming ◽  
Lian Cun Zheng ◽  
Xin Xin Zhang
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Power Law ◽  
Swirling Flow ◽  
Mhd Flow ◽  
Rotating Disk ◽  
Electrically Conducting ◽  
Flow And Heat Transfer ◽  
Power Law Index ◽  
Shear Thinning Fluid

This paper studied the Magneto hydrodynamic (MHD) flow and heat transfer of an electrically conducting non-Newtonian fluid over a rotating disk in the presence of a uniform magnetic field. The steady, laminar and axial-symmetric flow is driven solely by the rotating disk, and the incompressible fluid obeys the inelastic Ostwald de-Waele power-law model. The governing differential equations were reduced to a set of ordinary differential equations by utilizing the generalized Karman similarity transformation. The nonlinear two-point boundary value problem is solved by multi-shooting method. Numerical results show that the magnetic parameter and the power-law index have significant effects on the swirling flow and heat transfer.

scholarly journals Non-Newtonian effect on heat transfer and entropy generation of natural convection nanofluid flow inside a vertical wavy porous cavity

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Mahbuba Tasmin ◽  
Preetom Nag ◽  
Zarin T. Hoque ◽  
Md. Mamun Molla
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Entropy Generation ◽  
Power Law ◽  
Volume Fraction ◽  
Local Entropy ◽  
Nanofluid Flow ◽  
Porosity Level ◽  
Power Law Index ◽  
Local Entropy Generation

AbstractA numerical study on heat transfer and entropy generation in natural convection of non-Newtonian nanofluid flow has been explored within a differentially heated two-dimensional wavy porous cavity. In the present study, copper (Cu)–water nanofluid is considered for the investigation where the specific behavior of Cu nanoparticles in water is considered to behave as non-Newtonian based on previously established experimental results. The power-law model and the Brinkman-extended Darcy model has been used to characterize the non-Newtonian porous medium. The governing equations of the flow are solved using the finite volume method with the collocated grid arrangement. Numerical results are presented through streamlines, isotherms, local Nusselt number and entropy generation rate to study the effects of a range of Darcy number (Da), volume fractions (ϕ) of nanofluids, Rayleigh numbers (Ra), and the power-law index (n). Results show that the rate of heat transfer from the wavy wall to the medium becomes enhanced by decreasing the power-law index but increasing the volume fraction of nanoparticles. Increase of porosity level and buoyancy forces of the medium augments flow strength and results in a thinner boundary layer within the cavity. At negligible porosity level of the enclosure, effect of volume fraction of nanoparticles over thermal conductivity of the nanofluids is imperceptible. Interestingly, when the Darcy–Rayleigh number $$Ra^*\gg 10$$ R a ∗ ≫ 10 , the power-law effect becomes more significant than the volume fraction effect in the augmentation of the convective heat transfer process. The local entropy generation is highly dominated by heat transfer irreversibility within the porous enclosure for all conditions of the flow medium. The particular wavy shape of the cavity strongly influences the heat transfer flow pattern and local entropy generation. Interestingly, contour graphs of local entropy generation and local Bejan number show a rotationally symmetric pattern of order two about the center of the wavy cavity.

scholarly journals Numerical Simulation of Heat Mass Transfer Effects on MHD Flow of Williamson Nanofluid by a Stretching Surface with Thermal Conductivity and Variable Thickness

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 684
Author(s):  
Saeed Islam ◽  
Haroon Ur Rasheed ◽  
Kottakkaran Sooppy Nisar ◽  
Nawal A. Alshehri ◽  
Mohammed Zakarya
Keyword(s):  
Thermal Conductivity ◽  
Boundary Layer ◽  
Mass Transfer ◽  
Differential Equations ◽  
Variable Thickness ◽  
Heat Mass Transfer ◽  
Mathematical Formulation ◽  
Stretching Surface ◽  
Nanofluid Flow ◽  
The Impact

The current analysis deals with radiative aspects of magnetohydrodynamic boundary layer flow with heat mass transfer features on electrically conductive Williamson nanofluid by a stretching surface. The impact of variable thickness and thermal conductivity characteristics in view of melting heat flow are examined. The mathematical formulation of Williamson nanofluid flow is based on boundary layer theory pioneered by Prandtl. The boundary layer nanofluid flow idea yields a constitutive flow laws of partial differential equations (PDEs) are made dimensionless and then reduce to ordinary nonlinear differential equations (ODEs) versus transformation technique. A built-in numerical algorithm bvp4c in Mathematica software is employed for nonlinear systems computation. Considerable features of dimensionless parameters are reviewed via graphical description. A comparison with another homotopic approach (HAM) as a limiting case and an excellent agreement perceived.

scholarly journals Effects of heat source/sink on magnetohydrodynamic flow and heat transfer of a non-Newtonian power-law fluid on a stretching surface

2016 ◽  
Vol 20 (6) ◽  
pp. 1801-1811 ◽  
Author(s):  
Kishan Naikoti ◽  
Kavitha Pagdipelli
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Differential Equations ◽  
Power Law ◽  
Skin Friction Coefficient ◽  
Temperature Profiles ◽  
Slip Parameter ◽  
Source Sink ◽  
Power Law Index

Non-Newtonian boundary layer flow and heat transfer characteristics over a stretching surface with thermal radiation and slip condition at the surface is analyzed. The flow is subject to a uniform transverse magnetic field. The suitable local similarity transformations are used to transform the non-linear partial differential equations into system of ordinary differential equations. The non-linear ordinary differential equations are linearized by using Quasi-linearization technique. The implicit finite difference scheme has been adopted to solve the obtained coupled ordinary differential equations. The important finding in this communication is the combined effects of Magnetic field parameter M, power law index n, slip parameter l, radiation parameter R, surface temperature parameter g , heat source/sink parameter S, local Eckert number Ec, temperature difference parameter r, generalized local Prandtl number Pr on velocity and temperature profiles and also the skin-friction coefficient -f''(0)and heat transfer coefficient -?'(0) results are discussed. The results pertaining to the present study indicate that as the increase of magnetic field parameter, slip parameter decreases the velocity profiles, where as the temperature profiles increases for both Newtonian and non-Newtonian fluids. The power law index n and heat source/sink parameter decreases the dimensionless velocity and temperature profiles. The effect of radiation parameter, Eckert number leads to increase the dimensionless temperature. It is found that increasing the slip parameter has the effect of decreasing the skin-friction coefficient-f''(0)and heat transfer coefficient-?'(0).With the increase of power law index n is to reduce the skin-friction coefficient and increase the heat transfer coefficient.

Magnetohydrodynamic flow of Carreau liquid over a stretchable sheet with a variable thickness

2020 ◽  
Vol 16 (5) ◽  
pp. 1277-1293 ◽  
Author(s):  
B. Mahanthesh
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Activation Energy ◽  
Mass Transfer ◽  
Differential Equations ◽  
Chemical Reaction ◽  
Variable Thickness ◽  
Transfer Rate ◽  
Content Type ◽  
Biomedical Sensors

PurposeThe magnetohydrodynamic (MHD) flow problems are important in the field of biomedical applications such as magnetic resonance imaging, inductive heat treatment of tumours, MHD-derived biomedical sensors, micropumps for drug delivery, MHD micromixers, magnetorelaxometry and actuators. Therefore, there is the impact of the magnetic field on the transport of non-Newtonian Carreau fluid in the presence of binary chemical reaction and activation energy over an extendable surface having a variable thickness. The significance of irregular heat source/sink and cross-diffusion effects is also explored.Design/methodology/approachThe leading governing equations are constructed by retaining the effects of binary chemical reaction and activation energy. Suitable similarity transformations are used to transform the governing partial differential equations into ordinary differential equations. Subsequent nonlinear two-point boundary value problem is treated numerically by using the shooting method based on Runge–Kutta–Fehlberg. Graphical results are presented to analyze the behaviour of effective parameters involved in the problem. The numerical values of the mass transfer rate (Sherwood number) and heat transfer rate (Nusselt number) are also calculated. Furthermore, the slope of the linear regression line through the data points is determined in order to quantify the outcome.FindingsIt is established that the external magnetic field restricts the flow strongly and serves as a potential control mechanism. It can be concluded that an applied magnetic field will play a major role in applications like micropumps, actuators and biomedical sensors. The heat transfer rate is enhanced due to Arrhenius activation energy mechanism. The boundary layer thickness is suppressed by strengthening the thickness of the sheet, resulting in higher values of Nusselt and Sherwood numbers.Originality/valueThe effects of magnetic field, binary chemical reaction and activation energy on heat and mass transfer of non-Newtonian Carreau liquid over an extendable surface with variable thickness are investigated for the first time.

The Effect of Suction on the Swirling Flow of Non-Newtonian Fluid

2014 ◽  
Vol 501-504 ◽  
pp. 2081-2084
Author(s):  
Chun Ying Ming ◽  
Lian Cun Zheng ◽  
Xin Xin Zhang
Keyword(s):  
Differential Equations ◽  
Power Law ◽  
Shooting Method ◽  
Numerical Solutions ◽  
Swirling Flow ◽  
Similarity Transformation ◽  
Rotating Disk ◽  
Shear Thinning Fluids ◽  
Suction Or Injection ◽  
Power Law Index

The flow of an incompressible viscous power-law fluid over an infinite rotating disk with uniform suction or injection is studied. The governing differential equations, which are partial and coupled, are simplified to a set of ordinary differential equations by generalized Karman similarity transformation. Numerical solutions of the non-linear two point boundary value problem are obtained by multi-shooting method. The effects of the power-law index and the porous parameter on the velocity fields are discussed for shear thinning fluids.

scholarly journals Effects of Viscous Dissipation on the Thermal Boundary Layer of Pseudoplastic Power-Law Non-Newtonian Fluids Using Discretization Method and the Boubaker Polynomials Expansion Scheme

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Karem Boubaker ◽  
Botong Li ◽  
Liancun Zheng ◽  
Ali H. Bhrawy ◽  
Xinxin Zhang
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Viscous Dissipation ◽  
Power Law ◽  
Infinite Plate ◽  
Newtonian Fluids ◽  
Discretization Method ◽  
Boubaker Polynomials ◽  
Power Law Index ◽  
Expansion Scheme

Heat transfer of pseudoplastic power-law non-Newtonian fluids aligned with a semi-infinite plate is studied. Unlike in most classical works, the effects of viscous dissipation which is coupled with the temperature-dependent thermal diffusivity are considered in the energy equation. The discretization method is used to convert the governing partial differential equations into a set of nonlinear ordinary differential equations. The solutions are presented numerically by using the shooting technique coupled with the Newtonian method and the Boubaker polynomials expansion scheme. The effects of power-law index and the Zheng number on the dynamics are analyzed. The associated heat-transfer characteristics are also tabulated in some domains of the said parameters.

Influence of Homogeneous and Heterogeneous Chemical Reactions and Variable Thermal Conductivity on the MHD Maxwell Fluid Flow due to a Surface of Variable Thickness

2020 ◽  
Vol 401 ◽  
pp. 148-163 ◽  
Author(s):  
G. Sarojamma ◽  
K. Sreelakshmi ◽  
P. Krishna Jyothi ◽  
P.V. Satya Narayana
Keyword(s):  
Thermal Conductivity ◽  
Fluid Flow ◽  
Chemical Reaction ◽  
Variable Thickness ◽  
Nonlinear Differential Equations ◽  
Maxwell Fluid ◽  
Variable Thermal Conductivity ◽  
Scaling Analysis ◽  
Bulk Fluid ◽  
Power Law Index

In this report, the effects of homogeneous-heterogeneous autocatalytic chemical reaction together with the variable thermal conductivity in the Maxwell fluid flow due to nonlinear surface of variable thickness are investigated. Thermal radiation and heat generation / absorption effects are also incorporated in the analysis. Appropriate scaling analysis is implemented to reduce the mathematical model describing the physics of the problem in to a set of nonlinear differential equations and are subsequently solved computationally. Graphical illustrations indicating the effect of pertinent parameters on momentum, thermal and solutal boundary layers are presented and discussed. The study reveals that velocity distribution shows a decreasing (increasing) tendency for larger values of wall thickness parameter when the velocity power law index is less (greater) than unity. The concentration of the homogeneous bulk fluid with catalyst at the surface decreases with increasing chemical reaction rate parameters.

scholarly journals Jet Impingement Heat Transfer of Confined Single and Double Jets with Non-Newtonian Power Law Nanofluid under the Inclined Magnetic Field Effects for a Partly Curved Heated Wall

2021 ◽  
Vol 13 (9) ◽  
pp. 5086
Author(s):  
Fatih Selimefendigil ◽  
Hakan F. Oztop ◽  
Ali J. Chamkha
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Particle Size ◽  
Aspect Ratio ◽  
Power Law ◽  
Volume Fraction ◽  
Inclined Magnetic Field ◽  
Magnetic Field Effects ◽  
Power Law Nanofluid ◽  
Power Law Index

Single and double impinging jets heat transfer of non-Newtonian power law nanofluid on a partly curved surface under the inclined magnetic field effects is analyzed with finite element method. The numerical work is performed for various values of Reynolds number (Re, between 100 and 300), Hartmann number (Ha, between 0 and 10), magnetic field inclination (γ, between 0 and 90), curved wall aspect ratio (AR, between 01. and 1.2), power law index (n, between 0.8 and 1.2), nanoparticle volume fraction (ϕ, between 0 and 0.04) and particle size in nm (dp, between 20 and 80). The amount of rise in average Nusselt (Nu) number with Re number depends upon the power law index while the discrepancy between the Newtonian fluid case becomes higher with higher values of power law indices. As compared to case with n = 1, discrepancy in the average Nu number are obtained as −38% and 71.5% for cases with n = 0.8 and n = 1.2. The magnetic field strength and inclination can be used to control the size and number or vortices. As magnetic field is imposed at the higher strength, the average Nu reduces by about 26.6% and 7.5% for single and double jets with n greater than 1 while it increases by about 4.78% and 12.58% with n less than 1. The inclination of magnetic field also plays an important role on the amount of enhancement in the average Nu number for different n values. The aspect ratio of the curved wall affects the flow field slightly while the average Nu variation becomes 5%. Average Nu number increases with higher solid particle volume fraction and with smaller particle size. At the highest particle size, it is increased by about 14%. There is 7% variation in the average Nu number when cases with lowest and highest particle size are compared. Finally, convective heat transfer performance modeling with four inputs and one output is successfully obtained by using Adaptive Neuro-Fuzzy Interface System (ANFIS) which provides fast and accurate prediction results.

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