Particle penetration research through buildings’ cracks: Fid-Bau Portal

Particle penetration research through buildings’ cracks

Popescu, Lelia / Limam, Karim

Indoor air quality is a major factor as nowadays people spend most of their time in buildings being exposed to the indoor level of pollution. The rate of pollutant entry through a leakage can be expressed by means of a penetration factor. The present article aims to present a numerical model proposed by the authors able to determine the particles’ mass transfer from outside environment to the inside one as a result of a pressure difference between the two zones. The studied cracks had simple rectangular geometry. The chosen cracks’ heights were 1 mm (0.039 in.) and 3 mm (0.118 in.) with a length of 50 mm(1.968 in.). Both horizontal and vertical positions were studied for the crack. According to the reference data, three levels of pressure drops were studied: 1, 3, and 6 Pa. The most dangerous particle diameters span for the human health varies from 0.35 to 2.5 μm, and so we have chosen it. The injected particles were made of a solid with the density of 1050 kg/m³(65.54 lb/fi³) and had a spherical shape. A computational fluid dynamics program was used to predict both airflow fields and particles concentration distribution. The geometrical configuration studied in this article aims to reproduce an experimental setup realized by the authors in order to validate the numerical model with the experimental results. The diameters’ span considered in this study didn't show an important influence on the penetration factor for the studied cases. The developed numerical model showed to be stable and gave results in the expected range of experimental values. This numerical study was capable of clarifying some details that are not obvious out of the experimental results, as the particles’ trajectories, or to quantify the crack entrance effect.