Chebyshev finite difference method for the effects of variable viscosity and variable thermal conductivity on heat transfer from moving surfaces with radiation

2004 ◽  
Vol 43 (9) ◽  
pp. 889-899 ◽  
Author(s):  
Elsayed M.E Elbarbary ◽  
Nasser S Elgazery
2004 ◽  
Vol 82 (9) ◽  
pp. 701-715 ◽  
Author(s):  
E F Elshehawey ◽  
N T Eldabe ◽  
E M Elbarbary ◽  
N S Elgazery

In this paper, the problem of heat transfer to the magneto-hydrodynamic flow of a micropolar, viscous, incompressible, and electrically conducting fluid from an isothermal stretching sheet with suction and blowing through a porous medium under the effects of Hall and ion-slip currents and variable thermal conductivity is studied numerically by using the Chebyshev finite-difference method. The governing fundamental equations on the assumption of a small magnetic Reynolds number are approximated by a system of nonlinear ordinary differential equations. Details of the velocities and temperature fields are presented for the various values of the parameters of the problem, e.g., the magnetic, Hall, ion-slip, porous, thermal conductivity, and surface mass transfer parameters. The numerical results indicate that the velocity and the angular velocity increase as the permeability parameter increases. Also, the temperature decreases as the permeability parameter increases but it increases as the thermal conductivity parameter increases. PACS No.:45.65.+a


Author(s):  
Lucas Peixoto ◽  
Ane Lis Marocki ◽  
Celso Vieira Junior ◽  
Viviana Mariani

Mathematics ◽  
2021 ◽  
Vol 9 (24) ◽  
pp. 3153
Author(s):  
Nidal H. Abu-Hamdeh ◽  
Abdulmalik A. Aljinaidi ◽  
Mohamed A. Eltaher ◽  
Khalid H. Almitani ◽  
Khaled A. Alnefaie ◽  
...  

The current article presents the entropy formation and heat transfer of the steady Prandtl-Eyring nanofluids (P-ENF). Heat transfer and flow of P-ENF are analyzed when nanofluid is passed to the hot and slippery surface. The study also investigates the effects of radiative heat flux, variable thermal conductivity, the material’s porosity, and the morphologies of nano-solid particles. Flow equations are defined utilizing partial differential equations (PDEs). Necessary transformations are employed to convert the formulae into ordinary differential equations. The implicit finite difference method (I-FDM) is used to find approximate solutions to ordinary differential equations. Two types of nano-solid particles, aluminium oxide (Al2O3) and copper (Cu), are examined using engine oil (EO) as working fluid. Graphical plots are used to depict the crucial outcomes regarding drag force, entropy measurement, temperature, Nusselt number, and flow. According to the study, there is a solid and aggressive increase in the heat transfer rate of P-ENF Cu-EO than Al2O3-EO. An increment in the size of nanoparticles resulted in enhancing the entropy of the model. The Prandtl-Eyring parameter and modified radiative flow show the same impact on the radiative field.


Author(s):  
Chandrashekhar Varanasi ◽  
Jayathi Y. Murthy ◽  
Sanjay Mathur

In recent years, there has been a great deal of interest in developing meshless methods for computational fluid dynamics (CFD) applications. In this paper, a meshless finite difference method is developed for solving conjugate heat transfer problems in complex geometries. Traditional finite difference methods (FDMs) have been restricted to an orthogonal or a body-fitted distribution of points. However, the Taylor series upon which the FDM is based is valid at any location in the neighborhood of the point about which the expansion is carried out. Exploiting this fact, and starting with an unstructured distribution of mesh points, derivatives are evaluated using a weighted least squares procedure. The system of equations that results from this discretization can be represented by a sparse matrix. This system is solved with an algebraic multigrid (AMG) solver. The implementation of Neumann, Dirichlet and mixed boundary conditions within this framework is described, as well as the handling of conjugate heat transfer. The method is verified through application to classical heat conduction problems with known analytical solutions. It is then applied to the solution of conjugate heat transfer problems in complex geometries, and the solutions so obtained are compared with more conventional unstructured finite volume methods. Metrics for accuracy are provided and future extensions are discussed.


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