Утицај геометрије елемената за дистрибуцију ваздуха на експанзију ваздушног млаза у системима мешајуће вентилације

Abstract

Овим радом обухваћене су нумеричке симулације и експериментална испитивања експанзије турбулентног ваздушног млаза који се појавлљује у системима механичке вентилације.

This paper includes numerical simulations and experimental investigations of the expansion of a turbulent air jet that occurs in mechanical ventilation systems. Indoor air movement has a major impact on comfort levels and is a serious problem in many air-conditioned or ventilated rooms. Air is introduced into the room locally at relatively high velocities and it is generally accepted that the resulting jet has the appropriate symmetry and uniformity that are a consequence of a certain symmetry of the nal devices, and that they only aect its spread. However, parts of the ducts and various attachments for air direction control and volume ow rate balancing contribute to an uneven velocity eld at the neck of the air terminal devices, which is further reected in the resulting jet. The conducted research is dedicated to the issue of asymmetry and uneven ow distribution on air terminal devices that are widely used in HVAC systems. Numerical tests of the air jet generated on the ventilation grille with one row of individually adjustable non-diverged blades and with the opposed action blades damper unit were performed. During these tests, the maximum velocity of the jet was observed at dierent distances from the outlet. Depending on the damper openness, it would result in jet dierences and the range of propagation in the room. The four-sided ceiling diuser with plenum box and side entry was studied. The unevenness of ow in all directions for dierent types of equalizing elements was observed. The position and openness of the damper inuence the volume ow rate balancing on the uniformity of the plane jet in slot diusers with a plenum box and side duct connection was also considered. It will be shown that the above examples, chosen as unavoidable in everyday practical application and whose inuence is not considered on that occasion, to a greater or lesser extent aect the movement of air in a room. Validation of numerical results was performed through experimental measurements and visualization with smoke.