Numerical simulation of flow separation at the outlet of a vertical solar chimney by Lattice Bolztmann Method

Abstract

Solar chimneys use thermal effects from solar radiation heat to ventilate houses and buildings naturally. Performance of a solar chimney depends on flow structure inside its air channel. In this report, we focus on analyzing effects of flow reversal region at outlet of a vertical solar chimney on the induced air flow rate. We use Lattice Boltzmann Method to simulate flow field and temperature field inside the air channel of a two dimensional vertical solar chimney at low Rayleigh number. The numerical results show flow field and temperature field inside the air channel with and without flow reversal regions. A relationship between the ratio of the height and the gap of the air channel and the Rayleigh number at which there is no flow reversal region is also found.