Numerical analysis of the influence of natural convection in attics - A CFD analysis

Paper in proceeding, 2018

As the design of the building envelope has changed, the parameters that govern thermal insulation, air tightness and the complex heat transfer processes are often neglected. This aim of this research work is to numerically investigate the influence of natural convection in attics with joists and insulation. With the help of Computational Fluid Dynamics (CFD), more specifically the software ANSYS Fluent, 3D simulations are conducted for both porous layer and air cavity to estimate the magnitude of heat transfer. The same was executed for porous media with two different values of permeability. A suitable turbulence model has been applied to account for the highly sensitive buoyancy driven flow. The results are presented in form of dimensionless numbers, Nusselt number versus modified Rayleigh number. It can be concluded that the temperature difference and permeability play a vital role.