The acoustic performance of the different types of plenum boxes for ceiling panels
Abstract:
The aerodynamic noise generated by side entry plenum boxes intended for ceiling diffusers was studied. The plenum boxes in the inflow duct were tested in an anechoic room at low to moderate Reynolds numbers. Two characteristic phenomena were discussed: a way of fixing the cross-bar into the plenum box and vertical or horizontal throttle placement on the junction of the channel and plenum box on the acoustic parameters of plenum boxes. The characteristic peak in the LAeq spectrum moves to the higher frequencies with increased flow velocity linked with the flow around the crossbar inside the boxes. Additionally, the different positions of the throttle inside the plenum box were important for the acoustic parameters of the studied boxes. The vertical and horizontal positions of the throttle give various signals in the acoustic spectrum of studied objects.