Unsteady Mixed Convection Flow of a Reactive Casson Fluid in a Permeable Wall Channel Filled with a Porous Medium

2017 ◽  
Vol 377 ◽  
pp. 166-179 ◽  
Author(s):  
Oluwole Daniel Makinde ◽  
Lazarus Rundora
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Porous Medium ◽  
Mixed Convection ◽  
Shape Parameter ◽  
Casson Fluid ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Unsteady Mixed Convection ◽  
Fluid Parameter

In the current paper, we investigate the thermal decomposition in an unsteady mixed convection flow of a reactive Casson fluid in a vertical channel filled with a saturated porous medium. The channel walls are assumed to be permeable with fluid injection through the left wall and suction out of the right wall. There is heat dissipation caused by exothermic chemical reaction within the flow system. The dimensionless form of the momentum and energy equations will be solved numerically using a semi-discretization finite difference method and a fourth order Runge-Kutta-Fehlberg integration scheme. The influence of the Casson fluid parameter, the buoyancy parameter, the porous medium shape parameter, the Eckert number, the suction/injection Reynolds number, Frank-Kamenetskii parameter and the Prandtl number on velocity and temperature profiles, skin friction and Nusselt number as well as the thermal stability criteria are presented graphically and discussed quantitatively. It is revealed that increasing the Casson fluid parameter enhances the flow velocity, the fluid temperature and the skin friction but has a diminishing effect on the wall heat transfer rate. The suction/injection Reynolds number, the porous medium shape parameter and the buoyancy parameter enhance the rate of heat transfer at the channel walls.

Unsteady mixed convection flow at a three-dimensional stagnation point

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Amin Noor ◽  
Roslinda Nazar ◽  
Kohilavani Naganthran ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Mixed Convection ◽  
Stagnation Point ◽  
Three Dimensional ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Unsteady Mixed Convection

Purpose This paper aims to probe the problem of an unsteady mixed convection stagnation point flow and heat transfer past a stationary surface in an incompressible viscous fluid numerically. Design/methodology/approach The governing nonlinear partial differential equations are transformed into a system of ordinary differential equations by a similarity transformation, which is then solved numerically by a Runge – Kutta – Fehlberg method with shooting technique and a collocation method, namely, the bvp4c function. Findings The effects of the governing parameters on the fluid flow and heat transfer characteristics are illustrated in tables and figures. It is found that dual (upper and lower branch) solutions exist for both the cases of assisting and opposing flow situations. A stability analysis has also been conducted to determine the physical meaning and stability of the dual solutions. Practical implications This theoretical study is significantly relevant to the applications of the heat exchangers placed in a low-velocity environment and electronic devices cooled by fans. Originality/value The case of suction on unsteady mixed convection flow at a three-dimensional stagnation point has not been studied before; hence, all generated numerical results are claimed to be novel.

scholarly journals Mixed Convection Flow over an Unsteady Stretching Surface in a Porous Medium with Heat Source

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Syed Muhammad Imran ◽  
Saleem Asghar ◽  
Muhammad Mushtaq
Keyword(s):  
Porous Medium ◽  
Heat Source ◽  
Mixed Convection ◽  
Numerical Solutions ◽  
Saturated Porous Medium ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Continuous Increase ◽  
Unsteady Mixed Convection ◽  
Unsteady Stretching Surface

This paper deals with the analysis of an unsteady mixed convection flow of a fluid saturated porous medium adjacent to heated/cooled semi-infinite stretching vertical sheet in the presence of heat source. The unsteadiness in the flow is caused by continuous stretching of the sheet and continuous increase in the surface temperature. We present the analytical and numerical solutions of the problem. The effects of emerging parameters on field quantities are examined and discussed.

Influence of Thermal Radiation on the Unsteady Mixed Convection Flow of a Jeffrey Fluid over a Stretching Sheet

2010 ◽  
Vol 65 (8-9) ◽  
pp. 711-719 ◽  
Author(s):  
Tasawar Hayat ◽  
Meraj Mustafa
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Thermal Radiation ◽  
Deborah Number ◽  
Convection Flow ◽  
Jeffrey Fluid ◽  
Mixed Convection Flow ◽  
Suction Parameter ◽  
Unsteady Mixed Convection ◽  
Homotopy Analysis

This study is concerned with the effect of thermal radiation on the unsteady mixed convection flow of a Jeffrey fluid past a porous vertical stretching surface. The arising problems of flow and heat transfer are solved analytically by employing homotopy analysis method (HAM). It is observed that the flow field is influenced appreciably by the unsteadiness parameter ζ , suction parameter S, mixed convection parameter λ , Deborah number β , Prandtl number Pr, and the radiation parameter Nr. Our performed computations depict that the heat transfer rate is increased with increasing values of Pr, Nr, and ζ

Numerical study of laminar mixed convection flow in a lid-driven square cavity filled with porous media

2018 ◽  
Vol 28 (4) ◽  
pp. 857-877 ◽  
Author(s):  
Najib Hdhiri ◽  
Brahim Ben Beya
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Porous Media ◽  
Mixed Convection ◽  
Transfer Rate ◽  
Richardson Number ◽  
Convection Flow ◽  
Brinkman Model ◽  
Mixed Convection Flow ◽  
Content Type

Purpose The purpose of this study is to produce a numerical model capable of predicting the mixed convection flows in a rectangular cavity filled with a porous medium and to analyze the effects of several parameters on convective flow in porous media in a differentially heated enclosure. Design/methodology/approach The authors used the finite volume method. Findings The authors predicted and analyzed the effects of Richardson number, Darcy number, porosity values and Prandtl number in heat transfer and fluid flow. On other hand, the porosity and Richardson number values lead to reducing the heat transfer rate of mixed convection flow in a porous medium. Originality/value A comparison between Darcy–Brinkman–Forchheimer model and Darcy–Brinkman model is discussed and analyzed. The authors finally conclude that the Darcy–Brinkman model overestimates the heat transfer rate.

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