On the Inertial Range of Particles Under the Influence of Local Exhaust Hoods

This paper presents results from numerical simulations conducted to estimate the inertial range (stopping distance) of large aerosol particles ejected away from local exhaust hoods. Potential flow theory is used to specify the air velocity along the centerline of a flanged circular hood. A high-order Gear method is used to integrate the particle equations of motion with drag coefficients in the transitional range. The results allow for a relative comparison of hood performance based on the energy cost needed to stop the particle within a specified distance. Hood size is shown to be a critical factor, while the capture velocity generated by the hood at the point of particle ejection is of secondary importance.