Analysis of natural convection in a rhombic enclosure with undulations of the top wall – a numerical study

Dutta, Susanta; Biswas, Ashis; Pati, Sukumar

doi:10.1080/01430750.2019.1630304

Cited by 14 publications

(1 citation statement)

References 21 publications

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“…The optimal shape and tilt angle beside the Rayleigh number were indicated in terms of minimum entropy and maximum heat transfer. The natural convection analysis and entropy production in a rhombic enclosure with an undulated top wall was studied by Dutta et al 22 The influence of different inclination angles was examined numerically under the laminar flow regime (10 3 ≤ Ra ≤ 10 6 ) and revealed that irrespective of the undulations number, the increase of inclination angle significantly intensifies the heat transfer. Biswas et al 23 analyzed experimentally and numerically the influence of the heater's aspect ratio, Prandtl and Rayleigh numbers during natural convection within a rectangular cavity.…”

Section: Introductionmentioning

confidence: 99%

CFD‐based analysis of entropy generation due to mean and fluctuating fields during turbulent natural convection in a square enclosure

2022

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The current study aims to numerically investigate the entropy generation during the natural convection flow of air in a square cavity. The governing equations for the conservation of mass, momentum, energy, and turbulence are solved using a control volume‐based technique employing the commercial code Fluent. Runs have been performed for both laminar and turbulent flow regimes by varying the Rayleigh number (Ra) from 103 to 1010. On the other hand, various viscous distribution coefficients (ϕ = 10−4, 10−3, and 10−2) and constant Prandtl number (Pr = 0.71) were considered. Given the conflicting perspectives in the literature regarding the entropy generation under turbulent regimes, more research is needed to better understand the impact that the fluctuating flow has on entropy production. The four terms of entropy generation inherent to turbulent natural convection (entropy generation due to dissipation in the mean and the fluctuating velocity fields in addition to the heat flux due to the mean and the fluctuating temperature) are computed in the present work and compared to calculations based on only mean values of temperature and velocity gradients. It was found that taking into account the fluctuating terms of temperatures and velocities augment the total entropy generation by 10.10%, 14.43%, and, 17.70%, up to 32.60%, respectively, for Ra = 5 × 108, Ra = 109, Ra = 1.58 × 109, and Ra = 1010. The gain shows the tendency to increase with the Rayleigh number. Thus, the fluctuating terms cannot be neglected particularly for high Rayleigh numbers. Furthermore, unlike entropy production due to the mean flow field, numerical outcomes reveal that the generated irreversibilities due to fluctuating flow are located around the upper hot and the lower cold corners of the heated walls. In addition, a numerical relationship between the first and the second laws of thermodynamics has been derived. A promising result that emerged from this study has shown that the Nusselt number and therefore the first law of thermodynamics is sufficient to estimate the heat part of entropy generation without the necessity of using the second law.

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Section: Introductionmentioning

confidence: 99%

CFD‐based analysis of entropy generation due to mean and fluctuating fields during turbulent natural convection in a square enclosure

2022

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Thermal transport analysis for natural convection in a porous corrugated rhombic enclosure

2020

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A numerical study of fluid flow and heat transfer, applying natural convection is carried out in a porous corrugated rhombic enclosure. A uniform heating source is applied from the bottom boundary wall while the inclined side walls are maintained to a constant cold temperature and the top corrugated wall is retained at insulated condition inside the enclosure. The heat transfer and flow features are presented for a wide spectrum of Rayleigh numbers (Ra), 104 ≤ Ra ≤ 106, and Darcy numbers (Da), 10−3 ≤ Da ≤ 10−2. The number of undulations (n) for the top and bottom walls have been varied from 1 to 13 keeping the amplitude of undulation fixed. It is revealed that the characteristics of heat transfer are conceivably modulated by changing the parameter of the undulation number on the enclosure walls, specifically at the bottom and top. The influencing control of n in altering the heat transfer rate is felt maximum on the left wall and minimum for the right wall, and there is a strong interplay between Ra and Da together with n on dictating the heat transfer characteristics. The critical value, where heat transfer rate is observed as maximum is at n = 11 and thereafter the values decrease.

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Influence of Thermal Radiation on Natural Convection in a Square Enclosure

Dutta¹,

Pati

2021

Techno-Societal 2020

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Analysis of natural convection in a rhombic enclosure with undulations of the top wall – a numerical study

Cited by 14 publications

References 21 publications

CFD‐based analysis of entropy generation due to mean and fluctuating fields during turbulent natural convection in a square enclosure

CFD‐based analysis of entropy generation due to mean and fluctuating fields during turbulent natural convection in a square enclosure

Thermal transport analysis for natural convection in a porous corrugated rhombic enclosure

Influence of Thermal Radiation on Natural Convection in a Square Enclosure

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