Funding: GVT - Gesellschaft für Verfahrens-Technik e.V. (GVT-Nr.: GVT.2020.05)

Contact: Daniel Stoll

The aim of this research project is to improve the understanding of flow processes and deposition mechanisms in half masks (without breathing connection/breathing valve) made of electret nonwovens under real conditions of use with regard to both particle deposition/protection and the aging of the half masks. In addition, the findings are to be used for the development of optimized half masks. Some research work already exists in the field of half masks. However, these do not provide any insights into the influences of real conditions, such as wetting of the nonwoven fabric by droplets from the respiratory air and mechanical deformation during alternating flow directions (inhalation and exhalation) on the breathing resistance of the half masks. Furthermore, the flow dynamics through the filter medium of the half mask and leak zones in the contact of the half mask with the face are hardly studied so far. Consequently, there is a possibility of being infected with the SARS-CoV-2 virus despite wearing a tested half mask. To answer the questions, a combination of numerical and experimental studies is useful. The experiments (based on DIN EN 149) provide global measured variables, whereas the flow (and particle movement) can be resolved and described locally with simulations.