Three-dimensional computational fluid dynamics analysis of buoyancy-driven natural ventilation and entropy generation in a prismatic greenhouse

Aich, Walid; Kolsi, Lioua; Borjini, Naceur; A.A.A., Abdullah Al-Rashed; Ben, Habib Aissia; Oztop, F Hakan; Abu‐Hamdeh, Nidal H.

doi:10.2298/tsci151015052a

Cited by 19 publications

(13 citation statements)

References 22 publications

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“…The turbulent nature of the air flow was simulated by using the empirical turbulence model k-ε standard, a model that has been extensively validated in studies of natural ventilation of agricultural buildings, showing a good fit of the real airflow behavior with respect to the simulated process [7]. The buoyancy effects of air caused by gravity and air density changes were added to the momentum equation as a source term by the Boussinesq approximation, and this model is represented by Equation (2) [41].…”

Section: ∂(U∅) ∂Xmentioning

confidence: 99%

Contribution to the Sustainability of Agricultural Production in Greenhouses Built on Slope Soils: A Numerical Study of the Microclimatic Behavior of a Typical Colombian Structure

2021

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The use of covered structures is an alternative increasingly used by farmers to increase crop yields per unit area compared to open field production. In Latin American countries such as Colombia, productive areas are located in with predominantly hillside soil conditions. In the last two decades, farmers have introduced cover structures adapted to these soil conditions, structures for which the behavior of factors that directly affect plant growth and development, such as microclimate, are still unknown. Therefore, in this research work, a CFD-3D model successfully validated with experimental data of temperature and air velocity was implemented. The numerical model was used to determine the behavior of air flow patterns and temperature distribution inside a Colombian passive greenhouse during daytime hours. The results showed that the slope of the terrain affects the behavior of the air flow patterns, generating thermal gradients inside the greenhouse with values between 1.26 and 16.93 °C for the hours evaluated. It was also found that the highest indoor temperature values at the same time were located in the highest region of the terrain. Based on the results of this study, future researches on how to optimize the microclimatic conditions of this type of sustainable productive system can be carried out.

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Section: ∂(U∅) ∂Xmentioning

confidence: 99%

Contribution to the Sustainability of Agricultural Production in Greenhouses Built on Slope Soils: A Numerical Study of the Microclimatic Behavior of a Typical Colombian Structure

2021

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“…As a numerical method, we had recourse to the potential vector-vorticity formalism ( → ψ − → ω) which allows, in a 3D configuration, the elimination of the pressure, which is a delicate term to treat [16,17]. To eliminate this term, one applies the rotational to the equation of momentum.…”

Section: Governing Equationsmentioning

confidence: 99%

Effects of Movable-Baffle on Heat Transfer and Entropy Generation in a Cavity Saturated by CNT Suspensions: Three-Dimensional Modeling

Al‐Rashed

Aich

Kolsi

et al. 2017

Entropy

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Abstract:Convective heat transfer and entropy generation in a 3D closed cavity, equipped with adiabatic-driven baffle and filled with CNT (carbon nanotube)-water nanofluid, are numerically investigated for a range of Rayleigh numbers from 10 3 to 10 5 . This research is conducted for three configurations; fixed baffle (V = 0), rotating baffle clockwise (V+) and rotating baffle counterclockwise (V−) and a range of CNT concentrations from 0 to 15%. Governing equations are formulated using potential vector vorticity formulation in its three-dimensional form, then solved by the finite volume method. The effects of motion direction of the inserted driven baffle and CNT concentration on heat transfer and entropy generation are studied. It was observed that for low Rayleigh numbers, the motion of the driven baffle enhances heat transfer regardless of its direction and the CNT concentration effect is negligible. However, with an increasing Rayleigh number, adding driven baffle increases the heat transfer only when it moves in the direction of the decreasing temperature gradient; elsewhere, convective heat transfer cannot be enhanced due to flow blockage at the corners of the baffle.

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“…Yıldız [14] studied the cooling of a plate (1 m in height and 1 m in width), which is oriented vertical, and the results show that the surface temperatures of the plate at the inclination angle of 45° are relatively higher than those of the plate at the vertical state and those of the 20° inclined plate. Aich et al [15] studied numerically three-dimensional computational fluid dynamics analysis of buoyancy-driven natural ventilation and entropy generation in a prismatic greenhouse. Results are reported in terms of particles trajectories, iso-surfaces of temperature, mean Nusselt number, and entropy generation.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Natural Convection With Heated Tubes in Tunnel Greenhouse

Slatni

Djezzar

Messai³

2021

Journal of Thermal Engineering

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In this research, a numerical study was carried out on heat transfer by natural convection, in a closed tunnel greenhouse, in the range of the Rayleigh number (10 3 ≤Ra≤10 6 ). Were considered in the study, the number of heating tubes used (1≤Nt≤7), which were equidistant inside the greenhouse volume, when the bottom at an average temperature and cold Roof. The governing equations written in a bicylindrical coordinates were discretized using the finite volume method and vorticity-stream function formulation; the resulting algebraic equations were solved using successive over relaxation method (S.O.R). First, the effect of the Rayleigh number on heat transfer was examined for a fixed number of tubes as reference (Nt = 3) and the number of tubes was varied to investigate the influence on heat transfer in the greenhouse. Finally, the results obtained were summarized in the form of isotherms and streamlines, and for the average Nusselt number profile; in addition to the horizontal and vertical velocities and temperatures. However, in the reference case, for low Rayleigh numbers, the heat transfer is dominated by pure conduction.With the increase of the Rayleigh number and the number of tubes Nt, the natural convection becomes more dominant and the heat transfer increases, and in general the heat transfer increase with the increasing number of tubes.

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Three-dimensional computational fluid dynamics analysis of buoyancy-driven natural ventilation and entropy generation in a prismatic greenhouse

Cited by 19 publications

References 22 publications

Contribution to the Sustainability of Agricultural Production in Greenhouses Built on Slope Soils: A Numerical Study of the Microclimatic Behavior of a Typical Colombian Structure

Contribution to the Sustainability of Agricultural Production in Greenhouses Built on Slope Soils: A Numerical Study of the Microclimatic Behavior of a Typical Colombian Structure

Effects of Movable-Baffle on Heat Transfer and Entropy Generation in a Cavity Saturated by CNT Suspensions: Three-Dimensional Modeling

Numerical Investigation of Natural Convection With Heated Tubes in Tunnel Greenhouse

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