Transport phenomena through porous screens and openings: from theory to greenhouse practice.

The study of transport phenomena in multi-zone enclosures with permeable boundaries is fundamental for indoor climate control management. In this study, aspects concerning the air exchange through porous screens and openings, and heat transfer between the enclosure surface and inside air, were analysed. Basic physical laws were the starting point during the construction of the models. To illustrate the practical side of the research performed, the formulation developed was applied to the study of convective heat exchange within screened greenhouses, as well as to the study of airflow through greenhouse screens and window apertures. Concerning the airflow through porous screens and window openings, the results obtained thoroughly demonstrate the importance of inertia and viscous effects, as well as window openings' geometry effects, on fluid flow. The airflow characteristics of porous screens and the structure of fluctuation of wind velocity, were quantified. Regarding the study of free convection heat transfer within a screened greenhouse, the convective heat transfer coefficients between the air and the downward and the upward surfaces of the screen were obtained, among other results. The results obtained from this study can greatly contribute, in general, to a better climate control management of multi-zone enclosures, and specifically, to an improved application of porous screens and window apertures.

[1]  G. Bot.  Greenhouse climate: from physical processes to a dynamic model , 1983 .

[2]  G. L. Riskowski,et al.  Force and Static Pressure Resulting From Airflow Through Screens , 1993 .

[3]  T. D. Jong.  Natural ventilation of large multi-span greenhouses , 1990 .

[4]  S. Whitaker,et al.  The spatial averaging theorem revisited , 1985 .

[5]  George Papadakis,et al.  Mixed, forced and free convection heat transfer at the greenhouse cover , 1992 .

[6]  Michel Quintard,et al.  Ecoulement monophasique en milieu poreux: effet des hétérogénéités locales , 1987 .

[7]  G. C. Vliet,et al.  Turbulent Natural Convection on Upward and Downward Facing Inclined Constant Heat Flux Surfaces , 1975 .

[8]  S. Whitaker.  Flow in porous media I: A theoretical derivation of Darcy's law , 1986 .

[9]  F. Allard,et al.  Airflow through large openings , 1992 .

[10]  J. D. Holmes,et al.  MEAN AND FLUCTUATING INTERNAL PRESSURES INDUCED BY WIND , 1980 .

[11]  T. Kozai,et al.  A SIMULATION OF NATURAL VENTILATION FOR A MULTI-SPAN GREENHOUSE , 1978 .

[12]  Stanley Middleman,et al.  Flow of Viscoelastic Fluids through Porous Media , 1967 .

[13]  G. Bot,et al.  Modelling of transport phenomena near greenhouse screens , 1998 .

[14]  J. M. Coulson,et al.  Heat Transfer , 2018, Finite Element Method for Solids and Structures.

[15]  J. Bear.  Dynamics of Fluids in Porous Media , 1975 .

[16]  Luc Balemans,et al.  Assessment of criteria for energetic effectiveness of greenhouse screens , 1989 .

[17]  G. Lebon,et al.  A thermodynamical modelling of fluid flows through porous media: application to natural convection , 1986 .

[18]  Paul Fazio,et al.  A predictive stochastic model for indoor air quality , 1988 .

[19]  K.G.T. Hollands,et al.  Correlation equations for free convection heat transfer in horizontal layers of air and water , 1975 .

[20]  D. W. Etheridge,et al.  Crack flow equations and scale effect , 1977 .

[21]  Nicholas John Cook,et al.  The Designer's Guide To Wind Loading Of Building Structures , 1986 .

[22]  Paul Fazio,et al.  The influence of turbulent wind on air change rates—a modelling approach , 1991 .

[23]  S. Ergun.  Fluid flow through packed columns , 1952 .

[24]  Henry Liu,et al.  Helmholtz oscillation in building models , 1986 .

[25]  J. C. Bakker,et al.  Application of simulation models to optimize the control of thermal screens , 1998 .

[26]  Hideaki Imura,et al.  Natural-convection heat transfer from a plate with arbitrary inclination , 1972 .

[27]  Michel Quintard,et al.  Transport in ordered and disordered porous media II: Generalized volume averaging , 1994 .

[28]  Tadashi Takakura,et al.  Guide and Data for Greenhouse Air Conditioning , 1972 .

[29]  de H.F. Zwart,et al.  Analyzing energy-saving options in greenhouse cultivation using a simulation model , 1996 .

[30]  Antonio F. Miguel,et al.  Thermal radiation inside a single span greenhouse with a thermal screen , 1991 .

[31]  P. J. Jones,et al.  Computational fluid dynamics for building air flow prediction—current status and capabilities , 1992 .

[32]  B. J. Bailey.  THE EVALUATION OF THERMAL SCREENS IN GLASSHOUSES ON COMMERCIAL NURSERIES , 1981 .

[33]  P. H. Baker,et al.  Air flow through cracks , 1987 .