A numerical investigation of effects of a moving operator on airborne contamination removal in a cleanroom

This study deals with the influence of inlet airflow velocity on airflow distribution in a unidirectional type cleanroom taking into account a moving operator. Computational fluid dynamics was employed. The standard k-ε turbulence model was used to resolve the flow field and the trajectory of contaminants which were represented by a large number of particles was predicted by a Lagrangian approach. Dynamic meshes were applied to simulate the movement of the moving operator. A characteristic time to quantify the stabilization of the airflow was introduced. Local turbulence and recirculation zones were observed around the operator and the worktable due to the movement of the operator, which may trap contaminants and affect the cleanliness of the cleanroom. The contamination removal efficiency can be improved by increasing the airflow velocity from 0.2 m/s to 0.5 m/s, but the improvement becomes insignificant when the velocity is over 0.6 m/s.