Mixed convection boundary layer flow and heat transfer over a vertical plate embedded in a porous medium filled with a suspension of nano-encapsulated phase change materials

2019 ◽  
Vol 293 ◽  
pp. 111432 ◽  
Author(s):  
M. Ghalambaz ◽  
T. Groşan ◽  
I. Pop
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Porous Medium ◽  
Mixed Convection ◽  
Phase Change Materials ◽  
Vertical Plate ◽  
Convection Boundary Layer ◽  
Flow And Heat Transfer ◽  
Convection Boundary ◽  
Layer Flow

Unsteady mixed convection boundary layer flow along a symmetric wedge with variable surface temperature embedded in a saturated porous medium

2015 ◽  
Vol 25 (5) ◽  
pp. 1162-1175
Author(s):  
Saleh M. Al-Harbi ◽  
F. S. Ibrahim
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Porous Medium ◽  
Mixed Convection ◽  
Boundary Layer Flow ◽  
Convection Boundary Layer ◽  
Content Type ◽  
Unsteady Mixed Convection ◽  
Convection Boundary ◽  
Layer Flow

Purpose – The purpose of this paper is to study laminar two-dimensional unsteady mixed-convection boundary-layer flow of a viscous incompressible fluid past a symmetric wedge embedded in a porous medium in the presence of the first and second orders resistances. Design/methodology/approach – The governing boundary-layer equations along with the boundary conditions are first converted into dimensionless form by a non-similar transformation, and then resulting system of coupled non-linear partial differential equations were solved by perturbation solutions for small dimensionless time until the second order. Numerical solutions of the governing equations are obtained employing the implicit finite-difference scheme in combination with the quasi-linearization technique. The obtained results will be compared with earlier papers on special cases of the problem to examine validity of the method of solution. Findings – The effects of various parameters on the fluid velocity and fluid temperature as well as the wall heat transfer rate and skin-friction coefficient are presented graphically and in tabulated form. Originality/value – The study of heat transfer in porous media has been attracted the attention of many researchers in recent times due to the utmost importance in many different applications, including physical, geophysical and chemical applications. Also in different areas of engineering and modern purposes as oil refining, pollution of the air with poison gas, the process of mineral extraction, the design water tanks and study volcanic activity. Also has many uses in medicine, modern science, food products, textiles and ion exchange.

Linear Stability on the Local Thermal Nonequilibrium Model of Mixed Convection Boundary Layer Flow over a Moving Wedge in a Porous Medium: Viscous Dissipation and Radiation Effects

2021 ◽  
Vol 143 (4) ◽  
Author(s):  
Shashi Prabha Gogate S. ◽  
Bharathi M. C. ◽  
Ramesh B. Kudenatti
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Porous Medium ◽  
Differential Equations ◽  
Mixed Convection ◽  
Viscous Dissipation ◽  
Boundary Layer Flow ◽  
Convection Boundary Layer ◽  
Convection Boundary ◽  
Layer Flow

Abstract This paper studies the local thermal nonequilibrium (LTNE) model for two-dimensional mixed convection boundary-layer flow over a wedge, which is embedded in a porous medium in the presence of radiation and viscous dissipation. It is considered that the temperature of the fluid and solid phases is not identical; hence, we require two energy equations: one for each phase. The motion of the mainstream and wedge is approximated by the power of distance from the leading boundary layer. The flow and heat transfer in the LTNE phase is governed by the coupled partial differential equations, which are then reduced to nonlinear ordinary differential equations via suitable similarity transformations. Numerical simulations show that when the interphase rate of heat transfer is large, the system attains the local thermal equilibrium (LTE) state and so is for porosity scaled conductivity. When LTNE is strong, the fluid phase reacts faster to the mainstream temperature than the corresponding solid phase. The state of LTE rather depends on radiation and viscous dissipation of the model. Further, numerical solutions successfully predicted the upper and lower branch solutions when the velocity ratio is varied. To assess which of these solutions is practically realizable, an asymptotic analysis on unsteady perturbations for a large time leading to linear stability needs to be performed. This shows that the upper branch solutions are always stable and practically realizable. The physical dynamics behind these results are discussed in detail.

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