Modelling of Heat Transfer and Fluid Flow through a Granular Material and External Wall Barrier

Abstract

Heat and fluid flow simulations for granular material in wall barriers allow to design them in a way that maximally reduces the expenditures on utilisation of buildings. This paper demonstrates the solution to the problem of the passage of air through the external wall barrier. It shows how the temperature changes inside the wall barriers when the external temperature changes. Two types of partitions are tested: single-layer (granular material) and two-layer (granular and concrete material). The paper presents comparison of the results of the numerical model and in-house code with the experimental data. The numerical model applied is based on the unsteady equation of heat conduction (3D) and the Navier-Stokes equations. A high-order compact method in combination with the WENO scheme and predictor-corrector method are applied for the spatio-temporal discretisation. The flows of air and heat in the granular layers are modelled using immersed boundary technique, which allows to use Cartesian meshes for objects with very complex geometric shapes. The correctness of numerical model applied has been verified by comparisons with ANSYS Fluent results and experimental data obtained from measurements performed in a laboratory and in-situ.