Experimental study of vortex diffusers
This paper presents the results of experimental research performed to study the flow characteristics of isothermal jets issuing from vortex diffusers and to compare the vortex diffuser's performance with that of a conventional diffuser. Two styles of vortex diffusers and one conventional circular ceiling diffuser were used. For each diffuser, measurements were performed to obtain a velocity map, velocity profile, and velocity decay at three different flow rates. A series of flow visualization experiments was undertaken to capture the general behavior of jets issuing from the diffusers. Overall, it was found that the vortex diffusers produce slightly more induction (mixing) of ambient air in comparison to the conventional diffuser. This difference is probably caused by the turbulence produced as a result of the rotational motion near the outlet of the vortex diffusers. The rotational motion disappears within three outlet diameters, and the flow becomes radial.
Miller, P. L.
Experimental study of vortex diffusers.
ASHRAE Transactions, 102(2), 340–346.