exams

Prob. 1.1
In the pipe system shown in Fig., find the flow rate through the commercial steel pipes
(ε= 0.045 mm) if the following is given:
D= 0.05 m
L = 60 m water
Hst= 20 m
Hst= 20 m

Assume local loss coefficients as: L= 60 m

Entrance : Cent= 0.5 atm
Cent= 0.5
Globe Valve : Cv= 5 D= 5 cm Valve
C v= 5

Take water dynamic viscosity as 0.001 kg/m s.
(𝑄 = 0.0069 𝑚3 /𝑠)

Prob. 1.2
For the pipe system shown in Fig., specify the nominal size of clean commercial steel pipes
(ε= 0.045 mm) required for a flow rate 0.005 m3/s if the following are given:
Da= Db= Dc
La = 30 m , Lb = 6 m , Lc = 24 m
Hst= 20 m
Assume local loss coefficients as:
Entrance: Cent= 0.78
Elbow: Cb= 30 fT
Valve: Cv= 55 fT
Exit: Cex= 1.0
Take water dynamic viscosity as 0.001 kg/m s.

1




Water


La, Da



Va
Hst




Vb Lb, Db




2

Vc


Lc, Dc


1

, Prob. 1.3
In the pipe system shown in Fig., specify the nominal size of clean commercial steel pipes
(ε= 0.045 mm) required for a flow rate 0.01 m3/s if the following are given:
L = 100 m
Hst= 20 m water

Hst= 20 m
Assume local loss coefficients as:
L= 100 m
Entrance : Cent= 0.5
atm
Globe Valve : Cv= 5 Cent= 0.5
Valve
D
Cv= 5
Take water dynamic viscosity as 0.001 kg/m s.




Prob. 1.4
In the pipe system shown in Fig., find the flow rate through the commercial steel pipes
(ε= 0.045 mm) if the following is given:
D= 0.05 m
L = 200 m water
Hst= 20 m
Hst= 20 m

Assume local loss coefficients as: L= 200 m

Entrance : Cent= 0.5 P atm
Cent= 0.5
Globe Valve : Cv= 5 HP= 10 m D= 5 cm Valve
C v= 5

Take water dynamic viscosity as 0.001 kg/m s.




2