Prediction of the temporal evolution of microparticle resuspension in ventilated duct during a fan start by a Monte Carlo model

Abstract

When a fan is turned on in a Heating Ventilating and Air Conditioning (HVAC) duct, it firstexhibits a transient airflow period (acceleration regime) which is then followed by a constantairflow (steady state regime). Understanding particle resuspension in such realistic airflowscenario could prevent contamination of the surrounding environment and improvethe indoor air quality. For this purpose, this work analyzes the temporal evolution of thisphenomenon and relates it along with the instantaneous properties of the airflow pattern.To achieve this goal, a Monte Carlo (MC) numerical model is adapted in order to take intoaccount the temporal airflow pattern during both accelerated and steady state regime. Thenumerical results obtained with this new version of the Monte Carlo model are comparedwith previous resuspension experiments performed in a ventilated duct using such airflowscenarios. A detailed analysis of the velocity profile and, above all, of its fluctuations is takeninto account in the model. In light of the results obtained, it can be determined that thisinstantaneous aerodynamic information is essential for the model to provide realistic resultsin a non-steady airflow scenario.