Contribution a l’etude numerique de la convection naturelle laminaire d’un systeme radial de chauffage solaire

Abstract

The author proposes in this thesis, a numerical study of laminar natural convection in a Solar Heater Radial System. Two different simulations were performed. First, the two-dimensional governing equations have been solved numerically using a validate computer code. The Transported fluid is the air (Pr =0.702), it is considered as a Newtonian and incompressible fluid based on the Boussinesq approximations, the governing equations are taken to be in the vorticitystream function formulation in hyperbolic coordinates. For heating conditions we suppose an isothermal walls of the collector (Tc for the ground and Tf for the roof, with Tc > Tf). Solution of the defined equations has been done with numerical control volume method. We examined the effect of the system geometry on the natural convection phenomenon in the solar chimney. Finally, the simulation results have been given as airflows and temperature patterns. Then, a 3D numerical simulation was performed using the FLUENT software to simulate a three-dimensional model of a solar chimney power plant. The simulation was performed for the geometry of the Manzanares prototype, in Spain. The distribution of temperature, velocity and pressure in the system are shown for three different solar radiations. Good quantitative agreement was obtained between the experimental and numerical data and our numerical results. This result (2D and 3D) will let the solar chimney designer locate correctly the turbine in the solar chimney power plant and estimate the power that could be exploited.