E1C09 09/14/2010
15:5:2 Page 422
9.40 In order to measure the flow rate in a 2 m  2 m air conditioning duct, an engineer uses a pitot-static
probe to measure dynamic head. The duct is divided into nine equal rectangular areas with the
pressure measured at the center of each. Based on the results below, estimate the flow rate for air at
15
C and 1 atm.
Position
1
2
3
4
5
6
7
8
9
H (mm H 2 O)
5.0
6.0
6.5
6.0
5.0
6.5
7.5
7.0
5.0
422 Chapter 9 Pressure and Velocity Measurements
15:5:2 Page 422
9.40 In order to measure the flow rate in a 2 m  2 m air conditioning duct, an engineer uses a pitot-static
probe to measure dynamic head. The duct is divided into nine equal rectangular areas with the
pressure measured at the center of each. Based on the results below, estimate the flow rate for air at
15
C and 1 atm.
Position
1
2
3
4
5
6
7
8
9
H (mm H 2 O)
5.0
6.0
6.5
6.0
5.0
6.5
7.5
7.0
5.0
422 Chapter 9 Pressure and Velocity Measurements