In this work, a comparative numerical study of natural convection in a channel with two types of walls was presented. This channel has two flat walls in the first case and flat wall and sinusoidal one in the second case. This type of channels is used as a thermosyphon system under the tiles of the roof of the buildings. It maximizes natural ventilation and minimizes the solar energy absorbed by the construction.
To evaluate the effectiveness of the air channel, a numerical model is developed for the studied thermosyphon using the software FLUENT.
The governing equations are solved by using the software Fluent where the SIMPLER algorithm is used for the coupling of velocity and pressure. The flow is turbulent and the turbulence is modeled by using the k-ε model.
The distributions of speeds, temperatures and mass flow induced are determined. The obtained results are in good agreement with the experimental ones.
A comparative study of the air flow in the second type of channel with sinusoidal wall was performed, it fined that it gives a flow with a high rate and the use of the corrugated surface allows us to increase the heat transfer to the fluid and the rate of mass flow without affecting the length of the channel.