Development of Multiphysics Models for the Study of Airflow and Thermal Effects During the Use of Filtering Facepiece Respirators

To provide good protection, a Filtering Facepice Respirator (FFR) must be properly adjusted to ensure a satisfactory seal against the external working environment. None of the tests currently in use can accurately locate potential air leaks and determine a fit factor. T he aim o f t he project is to develop an analysis station for assessing these quantities using infrared imaging methods. The development of a multiphysics model of the different situation will become a tool for better understanding phenomena by simulating situations that are difficult t o verify experimentally. This paper proposes the development of multiple multiphysics models using COMSOL Multiphysics® Software to simulate the thermal effects of air leaks during the use of FFR. The construction of various geometries, transitioning from a simple 2D model to a 3D model closely resembling real-life situations, is detailed as follows. The implementation of diverse physics and meshing techniques related to the problem, including thermal dynamics and fluid mechanics h as been thoroughly studied. A pivotal aspect considered in this context is the respiratory cycle. The preliminary results show that 1) the impact of humidity on heat exchange is low and negligible to a first approximation, 2) the variation of the flow rate at the leak is linked to its size, and, in particular, 3) the temperature evolution in zones proximate to the leaks as calculated by the model are compared with the experimental results obtained with an infrared camera. As part of a broader project, these models will be instrumental in comparing and validating forthcoming experimental results. The simulation results obtained will also be used to feed a database that will be used in artificial intelligence model asp art o f t he development of the analysis station.