The fluid mechanics of a two-dimensional Aaberg exhaust hood

In this paper a study of the air flow pattern created by a two-dimensional Aaberg exhaust hood local ventilation system is presented. A mathematical model of the flow, in terms of the stream function ψ, is derived analytically for both laminar and turbulent injections of fluid. Streamlines and lines of constant speed deduced from the model are examined for various values of the governing dimensionless operating parameter and predictions are given as to the area in front of the hood from which the air can be sampled. The effect of the injection of fluid on the centre-line velocity of the flow is examined and a comparison of the results with the available experimental data is given. © 1992.