Conjugate natural convection in a square cavity with finite thickness horizontal walls

Mobedi, Moghtada

doi:10.1016/j.icheatmasstransfer.2007.09.004

Cited by 54 publications

(28 citation statements)

References 24 publications

(28 reference statements)

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“…Costa [2] reviewed studies on heatline visualization technique and summarized its application. Mobedi et al [3,4] used the heatline technique to observe heat transport in the entire domain of a square cavity with thick horizontal walls. Mobedi et al [5] also divided heatfunction equation into the diffusion and convection heatfunctions by using superposition rule.…”

Section: Introductionmentioning

confidence: 99%

Visualization of heat flow in a vertical channel with fully developed mixed convection

Çelik

Mobedi

2012

International Communications in Heat and Mass Transfer

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A study on visualization of heat flow in three channels with laminar fully developed mixed convection heat transfer is performed. The first channel is filled with completely pure fluid; the second one is completely filled with fluid saturated porous medium. A porous layer exists in the half of the third channel while another half is filled with pure fluid. The velocity, temperature and heat transport fields are obtained both by using analytical and numerical methods. Analytical expression for heat transport field is obtained and presented. The heatline patterns are plotted for different values of Gr/Re, thermal conductivity ratio, Peclet and Darcy numbers. It is found that the path of heat flow in the channel strongly depends on Peclet number. For low Peclet numbers (i.e., Pe = 0.01), the path of heat flow is independent of Gr/Re and Darcy numbers. However, for high Peclet numbers (i.e., Pe = 5), the ratio of Gr/Re, Darcy number and thermal conductivity ratio influence heatline patterns, considerably. For the channels with high Peclet number (i.e., Pe = 5), a downward heat flow is observed when a reverse flow exits.

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Section: Introductionmentioning

confidence: 99%

Visualization of heat flow in a vertical channel with fully developed mixed convection

Çelik

Mobedi

2012

International Communications in Heat and Mass Transfer

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“…These physical phenomena involve different heat transfer processes (coupling convection/conduction) which can affect several aspects related to sustainable architecture and design of buildings and cities, such as the reduction of energy demand [1][2][3][4][5][6], the decrease of the environmental impact [7,8] and the analysis of the urban canyon effect [9,10]. Differentially heated enclosures have been widely studied in the past [11][12][13][14][15]. However, the complexity of the problem has led the researchers to apply several simplifications in the analysis of these phenomena, such as setting the outdoor conditions as steady or considering indoor microclimate as a controlled environment (where the interior conditions are set, and, if required, dynamically controlled by an HVAC system).…”

Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamic Modelling of Thermal Periodic Stabilized Regime in Passive Buildings

et al. 2016

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Abstract:The periodic stabilized regime is the condition where the temperature of each point of a certain environment varies following a periodic law. This phenomenon occurs in many practical applications, such as passive or ancient buildings not equipped with Heating, Ventilating and Air Conditioning HVAC systems and located in latitudes where the temperature greatly varies with Earth's daily cycles. Despite that, the study of transient phenomena is often simplified, i.e., considering negligible the thermal response of the indoor microclimate. An exact solution to enclosures whose microclimate is free to evolve under a periodic stabilized regime does not exist nowadays, also from an analytical point of view. The aim of this study is to parametrically analyze the thermal variations inside a room when a transient periodic temperature is applied on one side. The phenomenon has been numerically studied through Computational Fluid Dynamics (CFD) and analytically validated using a function that reproduces the daily variation of the outdoor temperature. The results of this research would lay the groundwork to develop analytical correlations to solve and predict the thermal behavior of environments subject to a periodic stabilized regime.

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“…Dalal and Das [9] visualized heat transport by the heatline technique for a complicated enclosure. Mobedi et al [10,11] used the heatline technique to observe heat transport in the entire domain of a square cavity with thick horizontal walls. Recently, the heatline and streamline formulations were employed by Basak and Roy [12] to demonstrate the heat flow for differentially and distributed heating walls within cavities.…”

Section: Introductionmentioning

confidence: 99%

Visualization of diffusion and convection heat transport in a square cavity with natural convection

Mobedi

Özkol

Sundén

2010

International Journal of Heat and Mass Transfer

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a b s t r a c tIn this study, the total heatfunction equation which includes diffusion and convection transport is divided into the corresponding heatfunction equations. The superposition rule is used to obtain the mathematical definitions of diffusion and convection heatfunctions and corresponding boundary conditions. It is observed that the separate visualization of diffusion and convection heatlines provides significant information on understanding of the mechanism of heat transfer in a convective flow. The direction of the diffusion and convection heat transport as well as the strength of convection compared to the conduction in entire or in a portion of a domain can be visualized. The diffusion heatlines demonstrate a potential flow like behavior while convective heat flow rotates due to the source term of the convection heatfunction equation, similar to the rotation of fluid flow generated by fluid flow vorticity. The similarity between the streamfunction and the total heatfunction yields a concept of heat flow vorticity, X t . The obtained results show that the maximum absolute value of the convection heatfunction may be an appropriate parameter for determination of the convection strength. The diffusion and convection heatfunction equations for natural convection in a differentially heated square cavity for four different length of the heated surface on the right vertical wall as s p = L/4, L/2, 3L/4 and L and a fixed length of the cooled surface on the right vertical wall as L/4 are obtained and corresponding heatlines are drawn. The values of the conduction heatfunction are positive while the sign of convection heatfunction values is negative for the studied cases. Based on the distribution of total heatlines, two regions are detected in the cavity, an active region with the positive values of heatlines signifying dominant conduction heat transfer and a passive region with the negative heatfunction values in where convection heat flow is dominant and heat only rotates in a closed contour pattern. The variations of average Nusselt number, average of heat flow vorticity, maximum absolute values of convection heatfunction and streamfunction at different Rayleigh numbers and lengths of the heated surface are presented.

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Conjugate natural convection in a square cavity with finite thickness horizontal walls

Cited by 54 publications

References 24 publications

Visualization of heat flow in a vertical channel with fully developed mixed convection

Visualization of heat flow in a vertical channel with fully developed mixed convection

Computational Fluid Dynamic Modelling of Thermal Periodic Stabilized Regime in Passive Buildings

Visualization of diffusion and convection heat transport in a square cavity with natural convection

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