Capture Efficiency of the Aaberg Exhaust Hood and its Variation with Spatial Arrangement

Paper in proceedings (conference paper)

en

The paper deals with CFD simulations of a reinforced exhaust system (the Aaberg exhaust hood in particular). The reinforced suction effect is achieved by means of radial jet release. The radial jet deforms the flow pattern in front of the hood to a directional flow pattern. Unfortunately, the presence of an obstacle, such as a welding bench, leads to a defective operation of the hood. A number of CFD simulations have been undertaken in order to assess the effect of the obstacle size, its distance to the hood, and the hood declination from the normal of the obstacle surface, on the flow pattern and consequently the capture efficiency of the hood. Capture efficiency of selected cases was evaluated. For the purpose of capture efficiency evaluation, a heat source was defined within the model that imitated a metal arc welding process and introduced similar heat input into the domain altogether with a release of a passive scalar. The scalar concentration was then evaluated at the hood opening, thus capture efficiency could be calculated. The results of simulations indicate that the hood operation depends on the spatial arrangement of the hood and the obstacle. The best performance was achieved when the hood axis was aligned with the obstacle surface normal or the misalignment was small. Greater misalignment can be tolerated when the obstacle size is smaller than the hood-to-obstacle distance only.

CFD, Aaberg Exhaust Hood, Reinforced Exhaust System, Radial Jet, Industrial Ventilation, Local Exhaust Ventilation

2006-05-01

American Industrial Hygiene Association

Chicago, USA

Proceedings of 8th International Conference VENT2006

1–

8