Authors: Nacima Tadj; Mohammed Akli Nahal; Belkacem Draoui; Kittas Constantinos
Addresses: Mechanical Department, ENERGARID Laboratory, Bechar University, P.O. Box 417, Bechar 08000, Algeria ' Department of Geography and Development, Houari Boumedienne University, Algiers, Algeria ' Mechanical Department, ENERGARID Laboratory, Bechar University, P.O. Box 417, Bechar 08000, Algeria ' Department of Agriculture Crop Production and Rural Environment, University of Thessaly, Fytokou Str., 38446, N. Ionia Magnisias, Greece
Abstract: The location and the power of the heating devices determines in a large extend the flow and temperature patterns inside the greenhouse. The aim of this paper is to analyse the internal convective flows generated in a closed cultivated tunnel greenhouse. Numerical model of greenhouse, which has a size of (20 × 8 × 4.1) m, installing ducting system was evaluated with CFD simulation model (commercially available computational fluid dynamics CFD code CFX-13). The greenhouse was heated by hot air, distributed via clear perforated polyethylene ducts. The standard k-ε model was adopted to describe the turbulent transport. The dynamics' effects of the crop were simulated using the equivalent porous medium approach proposed by Darcy and reorganised by Forshheimer equation. The results are shown in the form of pressure, velocity and temperature contours. Better visualisation of the distribution of these parameters was obtained in order to homogenise the greenhouse climate. The pressure contours along he three perforated ducts show that the discharge through holes is not uniform because of the static pressure difference between upstream and downstream of the hole, as well as the angle and discharge coefficient variation of each hole.
Keywords: cultivated tunnel greenhouses; greenhouse heating; mixed convective airflow; CFD; computational fluid dynamics; perforated ducts; numerical simulation; polyethylene ducts; internal flows; convective flows; turbulence modelling; pressure contours; velocity contours; temperature contours; visualisation; greenhouse climate.
International Journal of Engineering Systems Modelling and Simulation, 2017 Vol.9 No.1, pp.3 - 11
Received: 09 Jun 2015
Accepted: 20 Nov 2015
Published online: 13 Jan 2017 *