Computational fluid dynamics and experimental study of turbulent natural convection coupled with surface thermal radiation in a cubic open cavity

2021 ◽  
Vol 198 ◽  
pp. 106360
Author(s):  
J.M.A. Navarro ◽  
J.F. Hinojosa ◽  
A. Piña-Ortiz
Keyword(s):  
Fluid Dynamics ◽  
Experimental Study ◽  
Computational Fluid Dynamics ◽  
Natural Convection ◽  
Thermal Radiation ◽  
Open Cavity ◽  
Turbulent Natural Convection

Computational fluid dynamics and experimental study of turbulent natural convection with surface thermal radiation in a cubic enclosure

2020 ◽  
Vol 31 (05) ◽  
pp. 2050065
Author(s):  
J. M. A. Navarro ◽  
J. F. Hinojosa ◽  
I. Hernández-López
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Experimental Data ◽  
Experimental Study ◽  
Computational Fluid Dynamics ◽  
Natural Convection ◽  
Thermal Radiation ◽  
Turbulence Models ◽  
Numerical Results ◽  
Turbulent Natural Convection

This paper reports a computational fluid dynamics and experimental study to analyze the effect of surface thermal radiation on the turbulent natural convection in a closed cubic cavity. Experimental and numerical results are compared for low and high wall emissivities. Experimental temperature profiles were obtained at six different depths and heights consisting of 14 thermocouples each. Several turbulence models were evaluated against experimental data. It was found that renormalized [Formula: see text]-[Formula: see text] and standard [Formula: see text]-[Formula: see text] turbulence models present the best agreement with the experimental data for emissivities of walls of 0.98 and 0.03, respectively. Thus, the numerical results of temperature fields and flow patterns were obtained with these models. From the results, it was found that the effect of thermal radiation on experimental heat transfer coefficients is significantly, increased between 48.7% ([Formula: see text]) and 50.16% ([Formula: see text]), when the emissivity of the walls increases from 0.03 to 0.98. Therefore, the radiative exchange should not be neglected in heat transfer calculations in cubic enclosures, even if the temperature difference between heated wall and cold wall is relatively small (between 15 and 30[Formula: see text]K).

Theoretical and experimental study of natural convection with surface thermal radiation in a side open cavity

2015 ◽  
Vol 75 ◽  
pp. 1176-1186 ◽  
Author(s):  
M. Montiel-González ◽  
J.F. Hinojosa ◽  
H.I. Villafán-Vidales ◽  
A. Bautista-Orozco ◽  
C.A. Estrada
Keyword(s):  
Experimental Study ◽  
Natural Convection ◽  
Thermal Radiation ◽  
Open Cavity

Numerical Investigation of Natural Convection in a Mono-Span Greenhouse

2012 ◽  
Author(s):  
Sunita Kruger ◽  
Leon Pretorius
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Natural Convection ◽  
Pitch Angle ◽  
Design Tool ◽  
Design Parameters ◽  
Two Dimensional ◽  
Cfd Model ◽  
Indoor Climate ◽  
Contour Plots

In this paper, the use of computational fluid dynamics is evaluated as a design tool to investigate the indoor climate of a confined greenhouse. The finite volume method using polyhedral cells is used to solve the governing mass, momentum and energy equations. Natural convection in a cavity corresponding to a mono-span venlo-type greenhouse is numerically investigated using Computational Fluid Dynamics. The CFD model is designed so as to simulate the climate above a plant canopy in an actual multi-span greenhouse heated by solar radiation. The aim of this paper is to investigate the influence of various design parameters such as pitch angle and roof asymmetry and on the velocity and temperature patterns inside a confined single span greenhouse heated from below. In the study reported in this paper a two-dimensional CFD model was generated for the mono-span venlo-type greenhouse, and a mesh sensitivity analysis was conducted to determine the mesh independence of the solution. Similar two-dimensional flow patterns were observed in the obtained CFD results as the experimental results reported by Lamrani et al [2]. The CFD model was then modified and used to explore the effect of roof pitch angle and roof asymmetry at floor level on the development of the flow and temperature patterns inside the cavity for various Rayleigh numbers. Results are presented in the form of vector and contour plots. It was found that considerable temperature and velocity gradients were observed in the centre of the greenhouse for each case in the first 40mm above the ground, as well as in the last 24mm close to the roof. Results also indicated that the Rayleigh number did not have a significant impact on the flow and temperature patterns inside the greenhouse, although roof angle and asymmetry did. The current results demonstrate the importance of CFD as a design tool in the case of greenhouse design.

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