Homework SourseThe face velocity of a ventilation system is 60 ftmin What w
The face velocity of a ventilation system is 60 ft/min. What would be the air velocity within the duct where the cross section area is one third of the hood cross section area?
20 ft/min.
60 ft/min.
180 ft/min.
540 ft/min.
| A. | 20 ft/min. | |
| B. | 60 ft/min. | |
| C. | 180 ft/min. | |
| D. | 540 ft/min. |
Solution
using Q=A*v
Q=quantity of air
A=cross sectional area
V= velocity
therefore at entry (hood)Q1= A1 * v1
at exit (inside duct) Q2 =A2 * v2
therefore
A1 * v1=A2 * v2
A1*60=(A1/3)*v2
v2=180 ft/min
