Forced Heat Transfer Convection in a Porous Channel with an Oriented Confined Jet

The present study is an analysis of the forced convection heat transfer in porous channel with an oriented jet at the inlet with uniform velocity and temperature distributions. The upper wall is insulated when the bottom one is kept at constant temperature higher than that of the fluid at the entrance. The dynamic field is analysed by the Brinkman-Forchheimer extended Darcy model and the thermal field is traduced by the energy one equation model. The numerical solution of the governing equations is obtained by using the finite volume method. The results mainly concern the effect of Reynolds number, jet angle and thermal conductivity ratio on the flow structure and local and average Nusselt numbers evolutions

Forced Heat Transfer Convection in a Porous Channel with an Oriented Confined Jet

The present study is an analysis of the forced convection heat transfer in porous channel with an oriented jet at the inlet with uniform velocity and temperature distributions. The upper wall is insulated when the bottom one is kept at constant temperature higher than that of the fluid at the entrance. The dynamic field is analysed by the Brinkman-Forchheimer extended Darcy model and the thermal field is traduced by the energy one equation model. The numerical solution of the governing equations is obtained by using the finite volume method. The results mainly concern the effect of Reynolds number, jet angle and thermal conductivity ratio on the flow structure and local and average Nusselt numbers evolutions

Forced Heat Transfer Convection in a Porous Channel with an Oriented Confined Jet

The present study is an analysis of the forced convection heat transfer in porous channel with an oriented jet at the inlet with uniform velocity and temperature distributions. The upper wall is insulated when the bottom one is kept at constant temperature higher than that of the fluid at the entrance. The dynamic field is analysed by the Brinkman-Forchheimer extended Darcy model and the thermal field is traduced by the energy one equation model. The numerical solution of the governing equations is obtained by using the finite volume method. The results mainly concern the effect of Reynolds number, jet angle and thermal conductivity ratio on the flow structure and local and average Nusselt numbers evolutions

Comparison between Two Local Thermal Non Equilibrium Criteria in Forced Convection through a Porous Channel

Two criteria are used and compared to investigate the local thermal equilibrium assumption in a forced convection through a porous channel. The first criterion is based on the maximum local temperature difference between the solid and fluid phases, while the second is based on the average of the local differences between the temperature of the solid phase and the fluid phase. For this purpose, the momentum and energy equations based on the Darcy-Brinkman-Forchheimer and the local thermal non equilibrium models are solved numerically using the finite volume method. The analysis focused on searching thermophysical parameters ranges which validate local thermal equilibrium hypothesis. Thus, by using the two criteria, the obtained results mainly revealed that this local thermal equilibrium assumption is verified for low thermal conductivity ratio and Reynolds number values and for high interstitial Biot number and porosity, while it is unfavorably affected by the high values of Prandtl number. However, it is also found that the parameters ranges corresponding to the local equilibrium validity depends on the selected local thermal non equilibrium criterion

Les solutions multiples en convection naturelle instationnaire dans une enceinte fermée: influence de l'angle d'inclinaison

Dans cette étude, nous étudions numériquement la convection naturelle instationnaire dans une cavité carréefermée, dont les parois horizontales sont adiabatiques et les parois verticales sont chauffées à la demi-hauteur inférieure, et refroidies dans leur partie supérieure de la cavité. Nous étudions deux cavités inclinées correspondant à un angle de 0 et 45 degrés. L’écoulement est laminaire et bidimensionnel. Les équations de transfert adimensionnelles exprimées en terme de vorticité et de fonction de courant, ont été résolues avec la méthode implicite des directions alternées à laquelle on a associé la méthode de l’élimination de GAUSS. Nous analysons les effets du nombre de Rayleigh et de l’inclinaison sur les routes vers le chaos qu’emprunte le système

Forced Heat Transfer Convection in a Porous Channel with an Oriented Confined Jet

The present study is an analysis of the forced convection heat transfer in porous channel with an oriented jet at the inlet with uniform velocity and temperature distributions. The upper wall is insulated when the bottom one is kept at constant temperature higher than that of the fluid at the entrance. The dynamic field is analysed by the Brinkman-Forchheimer extended Darcy model and the thermal field is traduced by the energy one equation model. The numerical solution of the governing equations is obtained by using the finite volume method. The results mainly concern the effect of Reynolds number, jet angle and thermal conductivity ratio on the flow structure and local and average Nusselt numbers evolutions

Forced convection in a self heating porous channel: Local thermal nonequilibium model

Laminar forced convection flow through a parallel plates channel completely filled with a saturated porous medium where occurs a uniform heat generation per unit volume with volumetric heat generation is investigated numerically. The Darcy-Brinkman model is used to describe the fluid flow. The energy transport mathematical model is based on the two equations model which assumes that there is no local thermal non-equilibrium between the fluid and the solid phases. The dimensionless governing equations with the appropriate boundary conditions are solved by direct numerical simulation. The effect of the controlling parameters, Biot number, thermal conductivities ratio, heat generation rate, and the Reynolds number on the local thermal equilibrium needed and sufficient condition is analyzed. The results reveal essentially that the local thermal equilibrium condition is unfavorably affected by the increase in the heat generation rate, the thermal conductivities ratio, and the decrease in the Biot number. In addition, for a given heat generation rate, the effect of Reynolds number on the local thermal equilibrium condition is reversed depending on the conductivities ratio threshold

NUMERICAL ANALYSIS OF HEAT EXCHANGE IN A POROUS CHANNEL WITH HEAT GENERATION AND LOCAL THERMAL NONEQUILIBRIUM

International audienceWe numerically investigate forced convection heat transfer with heat generation and local thermal nonequilibrium in a porous channel bounded by parallel plates. Macroscopic continuity, momentum, and energy equations are presented and solved. Local thermal nonequilibrium is considered by means of independent equations for the solid matrix and the working fl uid. The used numerical methodology is based on the control-volume approach. The eff ects of heat generation rate, thermal conductivity ratio, and Biot interstitial number on the local thermal equilibrium are presented. The main results obtained particularly show that lower values of the temperature diff erence (local thermal equilibrium) between the solid and the fl uid phases are obtained at low values of conductivity ratio and high values of Biot number, while large local temperature diff erences (local thermal nonequilibrium) are obtained for low Biot numbers values and high thermal conductivity ratios. Moreover, increasing heat generation rate generally leads to thermal nonequilibrium accentuation, particularly and most signifi cantly for low Biot number values

Analyse du chauffage périodique dans un cylindre poreux vertical

International audienceL'étude consiste en la modélisation numérique du transfert de chaleur par convection naturelle à travers un cylindre de stockage de grains disposé verticalement, ouvert à ses extrémités, et rempli d'un milieu poreux. La paroi du cylindre est portée à une température imposée variant d'une manière sinusoïdale dans le temps alors que le fluide est aspiré par le bas avec une température constante Le modèle d'écoulement de Darcy, sans établissement à la sortie de cylindre, a été employé pour modéliser notre problème. Dans le cas de température de paroi constante, deux types d'écoulements, avec et sans le recirculation, ont été obtenus selon les nombres de Rayleigh (Ra), le rapport de forme et la propriété thermophysique du milieu poreux (Bi).La comparaison entre température sinusoïdale et constante montre qu'il ya une similitude pour les faibles valeurs de Ra et X