air distribution trough holed duct
air distribution trough holed duct
(OP)
Hi all , I desire to calc how to distribute holes on a duct
so I can manage a given flow.
This is the task.
A 300 mm diameter 17000 mm length duct is to be perforated to handle 24 m3/minute of air, avaiable static pressure is 25 mm.
The duct will be at 3 meter hight , the area to be cooled is at 1,2 mt from floor.
The holes will be located at the 4 to 8 hour pattern.
Hope I make it clear , but if needed I can give more data on request.
Thanks in advance
Pardal





RE: air distribution trough holed duct
http://www.iperf.org/IPRF_CD.pdf they have stuff on pressure drops
RE: air distribution trough holed duct
The ratio of airflow to duct diameter was such that the distribution duct acted as a plenum thereby providing almost unifrom internal pressure along the entire length of the cloth duct. The ducting was supported on small steel cables installed across the building.
As I remember (15 yrs ago !) The DX fan/coil units were arranged along both sides of the building and each suplied two of the cloth ducts. The angle between each of the ducts was maybe 25/30 degrees. Total cooling load was perhaps 150 tons.
This cloth duct system was very inexpensise and provided very uniform air distribution. Sorry, that I can't remember any sources of supply.