Simulation of Night Cooling Through Natural Cross Ventilation using ANSYS (Fluent)

Abstract

n this study, we carried out a numerical simulation using CFD code “Fluent 14.0” to quantify night ventilation due to convective and radiative phenomena with well-defined boundary conditions. The configuration is an open square cavity. Top & bottom walls are adiabatic, however, vertical walls represent the left/interior wall and right/external wall provided with a top and a bottom opening, at Tcold & Thot temperatures, respectively. The computational domain is two-dimensional with open boundary conditions of the local Bernoulli type. The fluid is incompressible with Boussinesq's approximation and flow regime is stationary turbulent with k-ε RNG model on a 200 * 240 mesh refined near the walls, (ΔT = 10 °C). The obtained results allowed flow dynamics & thermal characterization as well as cooling integral quantities calculation. Introduction of surface emissivity influences heat transfer via active walls and increases (decreases) the lower (upper) passive wall temperature, while no effect was noted on the dynamics.