Presents four new empirical equations for the prediction of the centreline velocity in front of circular and slot exhaust openings, both plain and flanged, Such new, easy-to-use equations come from a mathematical treatment of the experimental data obtained by the authors. The suggested equations were developed by means of a regression analysis fitting the experimental data. Finally, the dimensionless predicted velocities inferred from the authors' equations were compared with the ones derived from the main empirical equations available in technical literature for the calculation of centreline velocity gradients in front of free-standing hoods.

KEYWORDS: year 1996, calculating, air, speed, exhaust hoods, comparing