OUTDOOR AND RETURN AIRFLOW MIXING WITH PARALLEL DAMPERS

摘要

Thermal mixing of two airstreams with dissimilar temperatures and velocities entering a mixing chamber, equipped with parallel air dampers, is studied experimentally. The thermal mixing for outdoor airflow ratios in the range between 15% and 45% was examined at several stations in the mixing chamber. At each flow ratio, the return airflow damper was kept fully open while the outdoor air damper angle was changed from 30° to 90° The results show that as the two streams flow into the mixing chamber and proceed downstream of the dampers-controlled inlets, most of the mixing occurs within a downstream distance equal to one height of the chamber. Furthermore, the results suggest that directing the two streams toward each other by altering the outdoor dampers from the fully to partially open position leads to improved mixing in the entrance region. However, this influence diminishes downstream of the dampers.