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Fluid Mechanics I – ME362*
Arab Academy for Science, Technology
and Maritime Transportation
Dr. Ahmed Khalifa Mehanna
Associate Professor
Room No: 223
Course Assistant Lecturer:
Eng. Omar Mostafa
Lecture 11:
Flow through Pipes – Part II
Fluid Mechanics I – ME362*
Recall the Typical pipe system components
Minor Loss in Pipe Flow
Total Head Losses
Example
Lecture Outline
Typical pipe system components
In addition to frictional losses, thereare minor losses due to
Entrances or exits
Expansions or contractions
Bends, elbows, tees, and otherfittings
Valves
Losses generally determined byexperiment and then correlated withpipe flow characteristics.
Loss coefficients are generally givenas the ratio of head loss to velocityhead.
Abrupt inlet, K ~ 0.5
g
VKh
g
Vh mmK
2or )
2(
22
Minor losses - Entrance Loss in Pipe
• A piping system may have many
minor losses which are all
correlated to V2/2g
• Sum them up to a total system
loss for pipes of the same
diameter
Where,
m
m
m
mfL KD
Lf
g
Vhhh
2
2
m lossheadTotalLh
m loss head Frictionalfh
mhm fitting forlossheadMinor
fitting fortcoefficienlossheadMinormK
Total Head Losses
Minor Head Loss for Fitting
Lists of loss coefficients K for four types of valve,
three angles of elbow fitting, and two tee connections
Given: Liquid in pipe has = 8 kN/m3.
Acceleration = 0. D = 1 cm, µ = 3x10-3 N.m/s2.
Find: Is fluid stationary, moving up, or moving
down? What is the mean velocity?
Solution: Energy eq. from z = 0 to z = 10 m
smV
*x*
).*(.V
μL
γDhV
γD
μLVh
mh
h
h
zp
g
Vhz
p
g
V
-
L
L
L
L
L
L
/04.1
1010332
0108000251
32
32
upward) (moving25.1
108
90
108000
000,110
8000
000,200
22
3
2
2
2
22
2
21
1
2
1
1
2
Example
Example
Example
Example
