6.2 Fans
211
Pressure
SP
VP
Point
1
0
0
2
−400
80
3
0
80
4
0
0
Case 3: Forcing system
1
2
3
4
5
Pressure
SP
VP
Point
1
0
0
2 a
−80
80
3
400
80
4
0
120
5
0
0
a The static and dynamic pressures have the same absolute value but with contrary signs. Therefore, the total
pressure is zero
You are requested to calculate the FTP and the FSP for each case.
Solution
Case 1:
Pressure
SP
VP
TP
Point
1
0
0
0
2
−400
80
−320
3
400
80
480
4
0
80
80
5
0
0
0
FTP = TP 3 − TP 2 = 480 − (−320) = 800
FSP = FTP − VP 3 = 800 − 80 = 720
Note the negative total pressure values in the suction duct.
211
Pressure
SP
VP
Point
1
0
0
2
−400
80
3
0
80
4
0
0
Case 3: Forcing system
1
2
3
4
5
Pressure
SP
VP
Point
1
0
0
2 a
−80
80
3
400
80
4
0
120
5
0
0
a The static and dynamic pressures have the same absolute value but with contrary signs. Therefore, the total
pressure is zero
You are requested to calculate the FTP and the FSP for each case.
Solution
Case 1:
Pressure
SP
VP
TP
Point
1
0
0
0
2
−400
80
−320
3
400
80
480
4
0
80
80
5
0
0
0
FTP = TP 3 − TP 2 = 480 − (−320) = 800
FSP = FTP − VP 3 = 800 − 80 = 720
Note the negative total pressure values in the suction duct.