A numerical study of mixed convection in a horizontal channel with a discrete heat source in an open cavity

2009 ◽  
Vol 28 (4) ◽  
pp. 590-598 ◽  
Author(s):  
Saiied M. Aminossadati ◽  
Behzad Ghasemi
2000 ◽  
Vol 123 (4) ◽  
pp. 698-702 ◽  
Author(s):  
C. Gururaja Rao ◽  
C. Balaji ◽  
S. P. Venkateshan

The results of a numerical study of the problem of two-dimensional, steady, incompressible, conjugate, laminar, mixed convection with surface radiation from a vertical plate with a flush-mounted discrete heat source are reported. The governing equations, written in vorticity-stream function form, are solved using a finite-volume based finite difference method. A hybrid grid system has been employed for discretization of the computational domain. The effects of (i) the magnitude and location of the heat source, (ii) the material and surface properties of the plate, and (iii) the free-stream velocity on both heat transfer and fluid flow have been studied. Based on a large set of (more than 550) numerical data, correlations have been developed for maximum and average non-dimensional plate temperatures and mean friction coefficient. A method for evaluating the forced convection mean friction coefficient component, which may be used in estimating the power input required for maintaining the flow, has been proposed.


Mathematics ◽  
2022 ◽  
Vol 10 (2) ◽  
pp. 178
Author(s):  
Mohammed Alghaseb ◽  
Walid Hassen ◽  
Abdelhakim Mesloub ◽  
Lioua Kolsi

In this study, a 3D numerical study of free ventilated room equipped with a discrete heat source was performed using the Finite Volume Method (FVM). To ensure good ventilation, two parallel openings were created in the room. A suction opening was located at the bottom of the left wall and another opening was located at the top of the opposite wall; the heat source was placed at various positions in order to compare the heating efficiency. The effects of Rayleigh number (103 ≤ Ra ≤ 106) for six heater positions was studied. The results focus on the impact of these parameters on the particle trajectories, temperature fields and on the heat transfer inside the room. It was found that the position of the heater has a dramatic effect on the behavior and topography of the flow in the room. When the heat source was placed on the wall with the suction opening, two antagonistic behaviors were recorded: an improvement in heat transfer of about 31.6%, compared to the other positions, and a low Rayleigh number against 22% attenuation for high Ra values was noted.


Entropy ◽  
2018 ◽  
Vol 20 (9) ◽  
pp. 664 ◽  
Author(s):  
Ammar Alsabery ◽  
Muneer Ismael ◽  
Ali Chamkha ◽  
Ishak Hashim

This numerical study considers the mixed convection and the inherent entropy generated in Al 2 O 3 –water nanofluid filling a cavity containing a rotating conductive cylinder. The vertical walls of the cavity are wavy and are cooled isothermally. The horizontal walls are thermally insulated, except for a heat source segment located at the bottom wall. The dimensionless governing equations subject to the selected boundary conditions are solved numerically using the Galerkin finite-element method. The study is accomplished by inspecting different ranges of the physical and geometrical parameters, namely, the Rayleigh number ( 10 3 ≤ R a ≤ 10 6 ), angular rotational velocity ( 0 ≤ Ω ≤ 750 ), number of undulations ( 0 ≤ N ≤ 4 ), volume fraction of Al 2 O 3 nanoparticles ( 0 ≤ ϕ ≤ 0.04 ), and the length of the heat source ( 0.2 ≤ H ≤ 0.8 ) . The results show that the rotation of the cylinder boosts the rate of heat exchange when the Rayleigh number is less than 5 × 10 5 . The number of undulations affects the average Nusselt number for a still cylinder. The rate of heat exchange increases with the volume fraction of the Al 2 O 3 nanoparticles and the length of the heater segment.


Author(s):  
Bernardo Buonomo ◽  
Oronzio Manca ◽  
Paolo Mesolella ◽  
Sergio Nardini

A numerical analysis of mixed convection in gas saturated metal foam in a horizontal channel with an open cavity heated at uniform heat flux on a vertical wall is studied numerically. Non-local thermal equilibrium and Brinkman-Forchheimer-extended Darcy model are assumed. Boussinesq approximation with constant thermophysical proprieties are considered. Results are carried out for an aluminium foam with 10 PPI and ε = 0.909, the fluid is air and for the assisting case. Results, for different Peclet and Rayleigh numbers, are given in terms of solid and fluid wall temperatures and local Nusselt numbers and stream function and temperature fields. Results show that diffusive effect determined lower temperature values inside the solid and the fluid temperatures are higher in all considered cases. The interaction between the forced flow in the channel and the buoyancy due to the heated wall determines different thermal and fluid dynamic behaviors.


2015 ◽  
Vol 17 (2) ◽  
pp. 219 ◽  
Author(s):  
Fatma Zamzari ◽  
Zouhaier Mehrez ◽  
Afif El Cafsi ◽  
Ali Belghith ◽  
Patrick Le Quéré

2020 ◽  
Vol 330 ◽  
pp. 01006
Author(s):  
F. Mebarek-Oudina ◽  
H. Laouira ◽  
A. Aissa ◽  
A. K. Hussein ◽  
M. El Ganaoui

In this work, a numerical study of mixed convection inside a horizontal channel with an open trapezoidal enclosure subjected to a discrete heat source in different locations is carried out. The heat source with the length of ε = 0.75, is maintained at a constant temperature. The air flow with a fixed velocity and a cold temperature enters the channel horizontally. The other walls of the enclosure and the channel are adiabatic. The results are presented in the form of the contours of velocity, isotherms and Nusselt numbers profiles for various heat source locations, Prandtl number (Pr = 0.71) and Reynolds number (Re = 100) respectively. The distribution of the isotherms depends significantly on the position of the heat source. We noted that the best heat transfer is detected where the heat source is placed in the top of the left .


1998 ◽  
Vol 22 (3) ◽  
pp. 269-289
Author(s):  
M. Lacroix

A numerical study has been conducted for the heat transfer from a discrete heat source by natural convection in air above coupled with conduction dominated melting of a phase change material (PCM) below via a wall of finite thermal diffusivity. Results indicate that the presence of a PCM layer underneath the wall significantly delays the temperature rise of the heat source. The time delay increases as the thermal diffusivity of the wail material decreases and as the thickness of the PCM layer increases. For high thermal conductivity wall materials [Formula: see text] the steady state heat source temperatures are similar and independent of the PCM layer. On the other hand, for [Formula: see text], the steady state temperatures are higher and dependent on the thickness of the PCM layer. A correlation is proposed in terms of the thickness of the PCM layer and the thermal conductivity ratio of the wall.


Sign in / Sign up

Export Citation Format

Share Document