scholarly journals Magnetohydrodynamic thin film and heat transfer of power law fluids over an unsteady stretching sheet with variable thermal conductivity

2016 ◽  
Vol 20 (6) ◽  
pp. 1791-1800 ◽  
Author(s):  
Yanhai Lin ◽  
Liancun Zheng ◽  
Botong Li ◽  
Xinxin Zhang
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Temperature Field ◽  
Power Law ◽  
Stretching Sheet ◽  
Numerical Solutions ◽  
Temperature Fields ◽  
Thin Film Flow ◽  
Unsteady Stretching Sheet ◽  
Power Law Fluids

This paper presents an investigation on the MHD thin film flow and heat transfer of a power law fluid over an unsteady stretching sheet. The effects of power law viscosity on a temperature field are taken into account with a modified Fourier?s law Proposed by Zheng by assuming that the temperature field is similar to the velocity field. The governing equations are reduced to a system of nonlinear ordinary differential equations. The numerical solutions are obtained by using the shooting method coupled with the Runge-Kutta method. The influence of the Hartmann number, the power law exponent, the unsteadiness parameter, the thickness parameter and the generalized Prandtl number on the velocity and temperature fields are presented graphically and analyzed. Moreover, the critical formula for parameters are derived which indicated that the magnetic field has no effect on the critical value.

scholarly journals Triple Solutions of Carreau Thin Film Flow with Thermocapillarity and Injection on an Unsteady Stretching Sheet

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3177 ◽  
Author(s):  
Kohilavani Naganthran ◽  
Ishak Hashim ◽  
Roslinda Nazar
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Differential Equations ◽  
Film Thickness ◽  
Stretching Sheet ◽  
Film Flow ◽  
Problem Solver ◽  
Thin Film Flow ◽  
Unsteady Stretching Sheet ◽  
Negative Film

Thin films and coatings which have a high demand in a variety of industries—such as manufacturing, optics, and photonics—need regular improvement to sustain industrial productivity. Thus, the present work examined the problem of the Carreau thin film flow and heat transfer with the influence of thermocapillarity over an unsteady stretching sheet, numerically. The sheet is permeable, and there is an injection effect at the surface of the stretching sheet. The similarity transformation reduced the partial differential equations into a system of ordinary differential equations which is then solved numerically by the MATLAB boundary value problem solver bvp4c. The more substantial effect of injection was found to be the reduction of the film thickness at the free surface and development of a better rate of convective heat transfer. However, the increment in the thermocapillarity number thickens the film, reduces the drag force, and weakens the rate of heat transfer past the stretching sheet. The triple solutions are identified when the governing parameters vary, but two of the solutions gave negative film thickness. Detecting solutions with the most negative film thickness is essential because it implies the interruption in the laminar flow over the stretching sheet, which then affects the thin film growing process.

scholarly journals Darcy Forchheimer nanofluid thin film flow of SWCNTs and heat transfer analysis over an unsteady stretching sheet

AIP Advances ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 015223 ◽  
Author(s):  
Saleem Nasir ◽  
Zahir Shah ◽  
Saeed Islam ◽  
Ebenezer Bonyah ◽  
Taza Gul
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Stretching Sheet ◽  
Film Flow ◽  
Heat Transfer Analysis ◽  
Thin Film Flow ◽  
Unsteady Stretching Sheet

Coupling Effects of Viscous Sheet and Ambient Fluid on Boundary Layer Flow and Heat Transfer in Power-Law Fluids

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Xiaochuan Liu ◽  
Liancun Zheng ◽  
Goong Chen ◽  
Lianxi Ma
Keyword(s):  
Heat Transfer ◽  
Power Law ◽  
Numerical Solutions ◽  
Skin Friction Coefficient ◽  
Similarity Solutions ◽  
Temperature Fields ◽  
Ambient Fluid ◽  
Local Skin ◽  
Flow And Heat Transfer ◽  
Power Law Fluids

This paper investigates the flow and heat transfer of power-law fluids over a stretching sheet where the coupling dynamics influence of viscous sheet and ambient fluid is taken into account via the stress balance. A modified Fourier's law is introduced in which the effects of viscous dissipation are taken into account by assuming that the thermal conductivity is to be shear-dependent on the velocity gradient. The conditions for both velocity and thermal boundary layers admitting similarity solutions are found, and numerical solutions are computed by a Bvp4c program. The results show that the viscous sheet and rheological properties of ambient fluids have significantly influences on both velocity and temperature fields characteristics. The formation of sheet varies with the viscosity of fluid and draw ratio, which then strongly affects the relations of the local skin friction coefficient, the local Nusselt number, and the generalized Reynolds number. Moreover, for specified parameters, the flow and heat transfer behaviors are discussed in detail.

Magnetohydrodynamics Thermocapillary Marangoni Convection Heat Transfer of Power-Law Fluids Driven by Temperature Gradient

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Yanhai Lin ◽  
Liancun Zheng ◽  
Xinxin Zhang
Keyword(s):  
Heat Transfer ◽  
Temperature Gradient ◽  
Differential Equations ◽  
Power Law ◽  
Numerical Solutions ◽  
Marangoni Convection ◽  
Convection Heat Transfer ◽  
Temperature Fields ◽  
Convection Heat ◽  
Power Law Fluids

This paper presents an investigation for magnetohydrodynamics (MHD) thermocapillary Marangoni convection heat transfer of an electrically conducting power-law fluid driven by temperature gradient. The surface tension is assumed to vary linearly with temperature and the effects of power-law viscosity on temperature fields are taken into account by modified Fourier law for power-law fluids (proposed by Pop). The governing partial differential equations are converted into ordinary differential equations and numerical solutions are presented. The effects of the Hartmann number, the power-law index and the Marangoni number on the velocity and temperature fields are discussed and analyzed in detail.

Flow and heat transfer of non-Newtonian power-law fluids over a stretching surface with variable thermal conductivity

2019 ◽  
Vol 15 (4) ◽  
pp. 686-698 ◽  
Author(s):  
Meng Yang ◽  
Yanhai Lin
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Temperature Field ◽  
Differential Equations ◽  
Power Law ◽  
Numerical Solutions ◽  
Physical Parameters ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Power Law Fluids

Purpose The purpose of this paper is to investigate the flow and heat transfer of power-law fluids over a non-linearly stretching sheet with non-Newtonian power-law stretching features. Design/methodology/approach The governing non-linear partial differential equations are reduced to a series of ordinary differential equations by suitable similarity transformations and the numerical solutions are obtained by the shooting method. Findings As the temperature power-law index or the power-law number of the fluids increases, the dimensionless stream function, dimensionless velocity and dimensionless temperature decrease, while the velocity boundary layer and temperature boundary layer become thinner for other fixed physical parameters. The thermal diffusivity varying as a function of the temperature gradient can be used to present the characteristics of flow and heat transfer of non-Newtonian power-law fluids. Originality/value Unlike classical works, the effect of power-law viscosity on the temperature field is considered by assuming that the temperature field is similar to the velocity field with modified Fourier’s law heat conduction for power-law fluid media.

scholarly journals Flow and Heat Transfer at a Nonlinearly Shrinking Porous Sheet:The Case of Asymptotically Large Powerlaw Shrinking Rates

2013 ◽  
Vol 18 (3) ◽  
pp. 779-791 ◽  
Author(s):  
K.V. Prasad ◽  
K. Vajravelu ◽  
I. Pop
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Power Law ◽  
Numerical Solutions ◽  
Skin Friction Coefficient ◽  
Temperature Fields ◽  
Shrinking Sheet ◽  
Arbitrary Power ◽  
Keller Box Method ◽  
Flow And Heat Transfer

Abstract The boundary layer flow and heat transfer of a viscous fluid over a nonlinear permeable shrinking sheet in a thermally stratified environment is considered. The sheet is assumed to shrink in its own plane with an arbitrary power-law velocity proportional to the distance from the stagnation point. The governing differential equations are first transformed into ordinary differential equations by introducing a new similarity transformation. This is different from the transform commonly used in the literature in that it permits numerical solutions even for asymptotically large values of the power-law index, m. The coupled non-linear boundary value problem is solved numerically by an implicit finite difference scheme known as the Keller- Box method. Numerical computations are performed for a wide variety of power-law parameters (1 < m < 100,000) so as to capture the effects of the thermally stratified environment on the velocity and temperature fields. The numerical solutions are presented through a number of graphs and tables. Numerical results for the skin-friction coefficient and the Nusselt number are tabulated for various values of the pertinent parameters.

scholarly journals Thin film flow of a second grade fluid in a porous medium past a stretching sheet with heat transfer

2018 ◽  
Vol 57 (2) ◽  
pp. 1019-1031 ◽  
Author(s):  
Noor Saeed Khan ◽  
Saeed Islam ◽  
Taza Gul ◽  
Ilyas Khan ◽  
Waris Khan ◽  
...  
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Porous Medium ◽  
Stretching Sheet ◽  
Film Flow ◽  
Second Grade ◽  
Thin Film Flow ◽  
Second Grade Fluid ◽  
Grade Fluid
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