scholarly journals Flow Reversal of Fully Developed Mixed Convection in a Vertical Channel with Chemical Reaction

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Habibis Saleh ◽  
Ishak Hashim ◽  
Sri Basriati
Keyword(s):  
Mixed Convection ◽  
Chemical Reaction ◽  
Buoyancy Force ◽  
Vertical Channel ◽  
Critical Values ◽  
Flow Reversal ◽  
Governing Equations ◽  
Reversed Flow ◽  
Exothermic Chemical Reaction

The present analysis is concerned with the criteria for the onset of flow reversal of the fully developed mixed convection in a vertical channel under the effect of the chemical reaction. The governing equations and the critical values of the buoyancy force are solved and calculated numerically via MAPLE. Parameter zones for the occurrence of reversed flow are presented. The exothermic chemical reaction is found to enhance the flow reversal and made flow reversal possible for symmetrical walls temperature.

Flow and Mixed Convection Heat Transfer in a Divergent Heated Vertical Channel

1996 ◽  
Vol 118 (3) ◽  
pp. 606-615 ◽  
Author(s):  
C. Gau ◽  
T. M. Huang ◽  
W. Aung
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Mixed Convection ◽  
Flow Reversal ◽  
Forced Flow ◽  
Vertical Position ◽  
Convection Flow ◽  
Reversed Flow ◽  
Buoyancy Parameter ◽  
Divergent Channel

This paper concerns an experimental study of the mixed convection flow and heat transfer inside a divergent channel formed by two plane walls. One of the side walls is oriented vertically and is heated uniformly, and the opposite wall is tilted at an angle of 3 deg with respect to the vertical position and is insulated. The ratio of the height to wall spacing at the flow inlet, which is at the smaller opening of the channel is 15. The Reynolds number of the main forced flow ranges from 100 to 4000 and the buoyancy parameter, Gr/Re2, varies from 0.3 to 907. Flow reversal is found to occur for both assisted and opposed convection. The effect of channel divergence on the occurrence and structure of the reversed flow and the heat transfer is presented and discussed. It is found that the divergence of the channel decelerates the mainstream such that flow reversal is initiated at a much lower buoyancy parameter. The adverse pressure gradient tends to push the reversed flow upstream and leads to a deeper penetration of the reversed flow into the channel The destabilization effect of the divergent channel can lead to breakdown of vortices and to transition to turbulent flow. This can significantly enhance the heat transfer. Temperature fluctuation measurements at different locations are used to indicate oscillations and fluctuations of the reversed flow. The effect of the buoyancy parameter on the Nusselt number and the reversed flow structure is discussed. The average Nusselt number is determined and correlated in terms of relevant nondimensional parameters for pure forced and mixed convection, respectively.

scholarly journals Laminar MHD Mixed Convection Flow Of Newtonian Fluid Between Vertical Parallel Plates Channel

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Nusselt Number ◽  
Mixed Convection ◽  
Newtonian Fluid ◽  
Vertical Channel ◽  
Convection Flow ◽  
Parallel Plates ◽  
Mixed Convection Flow ◽  
Governing Equations ◽  
Material Parameters ◽  
Developing Flow

This study investigates MHD mixed convection flow in a two parallel-plates vertical channel with reference to laminar, thermal and hydrodynamical developing flow of Newtonian fluid. The boundaries are considered to be isothermal with equal temperatures. The governing equations are solved numerically. Also, their dependence upon certain material parameters have been studied. Velocity, temperature, pressure gradient and Nusselt number profiles have also been presented

Finite-Element Analysis of Fully Developed Mixed Convection through a Vertical Channel in the Presence of Heat Generation/Absorption with a First-Order Chemical Reaction

2018 ◽  
Vol 388 ◽  
pp. 394-406
Author(s):  
Patil Mallikarjun ◽  
Raghavendra Vasudeva Murthy ◽  
Ulavathi Shettar Mahabaleshwar ◽  
Ali Jawad Chamkha ◽  
Giulio Lorenzini
Keyword(s):  
Finite Element ◽  
Mixed Convection ◽  
Chemical Reaction ◽  
Heat Generation ◽  
Vertical Channel ◽  
First Order ◽  
Thermal Buoyancy ◽  
Buoyancy Parameter ◽  
Order Chemical Reaction ◽  
First Order Chemical Reaction

Fully developed Mixed Convection through vertical channel in the presence of heat generation/absorption with first order chemical reaction is analyzed.The thermal boundary conditions are isothermal–isothermal for left and right walls of the channel and kept at different temperatures.The effect of thermal buoyancy parameter, concentration buoyancy parameter and heat generation/absorption parameter are studied. Also the flow field with the presence of first order chemical reaction is particularly analyzed. The governing equations are solved using finite element method.Velocity, temperature and concentration profiles are investigated for different values of the flow parameters.

scholarly journals Laminar aiding and opposing mixed convection in a vertical channel with an asymmetric discrete heating at one wall

2017 ◽  
Vol 21 (6 Part A) ◽  
pp. 2503-2515 ◽  
Author(s):  
Nassim Laouche ◽  
Abdelkader Korichi ◽  
Catalin Popa ◽  
Guillaume Polidori
Keyword(s):  
Mixed Convection ◽  
Rectangular Channel ◽  
Source Code ◽  
Vertical Channel ◽  
Governing Equations ◽  
Heat Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Extensive Analysis ◽  
Volume Method ◽  
Temperature Maps

Detailed numerical simulations are carried out for aiding/opposing mixed convection in a rectangular channel with an asymmetric discrete heating. The governing equations were solved by the finite volume method using OpenFoam? open source code. Based on streamline patterns, temperature maps, velocity and thermal profiles, and Nusselt number evolution an extensive analysis on the effects of Richardson number in the range ?5 to +5 for both opposed and aided buoyancy on the fluid flow and heat transfer characteristics is presented and discussed.

Computation of Mixed Convection and Volumetric Radiation in Vertical Channel Based on Hybrid Thermal Lattice Boltzmann Method

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Soufiane Derfoufi ◽  
Fayçal Moufekkir ◽  
Ahmed Mezrhab
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Richardson Number ◽  
Numerical Study ◽  
Vertical Channel ◽  
Governing Equations ◽  
Boltzmann Method ◽  
Thermal Lattice Boltzmann

The present paper presents a numerical study of mixed convection coupled with volumetric radiation in a vertical channel. The geometry of the physical model consists of two isothermal plates. The governing equations of the problem are solved using a hybrid scheme of the lattice Boltzmann method (LBM) and finite-difference method (FDM). The main objective of this study is to evaluate the influence of the Richardson number (Ri) and the emissivity of the walls (εi) on the heat transfer, on the flow, and on the temperature distribution. Results show that Richardson number and emissivity have a significant effect on heat transfer and air flow.

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