Experimental Studies on Air Distribution Using Ceiling Slot Diffusers in a Room

Nowadays, the ceiling slot diffuser is very popular in offices. However one of the problems, for the producer and designer of linear diffusers, is to determine and specify correctly the throw-length data, in order to achieve optimal air movement in the occupied zone. Here, experimental studies were conducted to identify the variation characteristics in jet behaviour for ceiling slot diffusers. Nine cases, covering different aspect ratios, were measured under isothermal conditions in two test rooms using traversing measurement systems. The results show that the critical aspect ratio for 2D and 3D jet flow is in the range of 30 to 59. The results also confirmed that the coefficient of jet maximum velocity decay depends on the details of the diffuser and thus should be identified for different products. The selection of the jet model should be determined by the aspect ratio of the jet slot to predict the maximum velocity decay.