A room measures 4.0 m by 3.9 m by 4.5 m. The heating and air-conditioning ducts to and from the room are circular with diameter 0.37 m and all the air in the room is to be exchanged every 14 min.

Question

A room measures 4.0 m by 3.9 m by 4.5 m. The heating and air-conditioning ducts to and from the room are circular with diameter 0.37 m and all the air in the room is to be exchanged every 14 min.
(a) What is the average flow rate?
  m3/s
(b) What is the necessary flow speed in the duct? (Assume that the density of the air is constant.)

drwls · Answer

(a) (Room volume)/(840 s) = ______ m^3/s (b) (Flow rate)/(duct area)