MMET 303 Exam II Review.pdf - MMET 303 Exam II Review...

MMET 303 – Exam II Review
• Closed book
• Allowed to bring:
– Equation sheet (double-sided is ok)
– Moody diagram, if you have one
– Two-sided Solution Methods handout
– Calculator
• Mott’s Chapters 8 – 12
• Homeworks: 5 – 8

Energy Equation
• Energy
in
= Energy
out
• Energy
in
+ Gains - Losses = Energy
out
• h
A
= Energy added to the fluid by a pump
• h
R
= Energy removed from the fluid by motors , etc.
• h
L
= Energy losses due to friction and minor losses
P
z
v
g
h h h
P
z
v
g
P
z
v
g
h
P
z
v
g
h h
A R L
A R L
1
1
1
2
2
2
2
2
1
1
1
2
2
2
2
2
2 2
2 2
J J
J J
± ± ± ² ² ± ±
± ± ± ± ± ± ±
4

Fluid Losses
Fluid
Characteristic
Laminar Turbulent
Need to know:
Velocity
Pipe Diameter
Viscosity
Density
Need to know:
Velocity
Pipe Diameter
Viscosity
Density
Roughness
5

Reynolds Number
Re
* * * v D v D
PIPE PIPE
U
P Q
Re < 2000 Laminar Flow
Re > 4000 Turbulent
2000 < Re < 4000 Critical Region or Transitional
Forces _ Viscous
Forces _ Inertia
Re
6

Figure 10-6: K for
Gradual Enlargement
21
D
2
/D
1
K

Energy loss due to friction
• Due to flowing fluid
• Proportional to velocity head:
• Proportional to the ratio Length of Pipe/Diameter of
Pipe (L/D)
• Darcy equation:
h
L
= Energy loss due to friction, N-m/N
or lb-ft/lb
L = length of flow stream or pipe, m