Thermodynamics I
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Transcript Thermodynamics I
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UGA 10/4
Benjamin Hamler
Toolbox
Reynolds Number
Relative roughness
Darcy Equation
HP Equation
Moody Chart
Surface roughness table
Material ε mm
Riveted Steel 0.90-9.0
Concrete 0.30-3.0
Wood stave 0.18-0.90
Cast iron 0.26
Galvanized iron 0.15
Commercial steel 0.045
Drawn tubing 0.0015
Plastic, glass 0.0
More Toolbox
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Explicit equation
Hazen- Williams
Hydraulic radius
HW Coefficient
Friction
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Pipe – Darcy Equation
Minor losses
Fittings
Valves
Special purpose components
Minor Losses
Head loss: streamline separation
Loss coefficient
Minor Losses
Inlet/exit
Expansion/
contraction
Bends/elbows
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Valves
Globe
Needle
Gate
Ball
Check
Butterfly
Diaphram
Loss Coefficient
hL = K V2/2g
Type of Component or Fitting
Minor Loss Coefficient
-ξ-
Tee, Flanged, Dividing Line Flow
0.2
Tee, Threaded, Dividing Line Flow
0.9
Tee, Flanged, Dividing Branched Flow
1.0
Tee, Threaded , Dividing Branch Flow
2.0
Union, Threaded
0.08
Elbow, Flanged Regular 90o
0.3
Elbow, Threaded Regular
90o
1.5
Elbow, Threaded Regular
45o
0.4
Elbow, Flanged Long Radius
90o
0.2
Elbow, Threaded Long Radius 90o
0.7
Elbow, Flanged Long Radius 45o
0.2
Return Bend, Flanged
180o
Return Bend, Threaded
180o
0.2
1.5
Globe Valve, Fully Open
10
Angle Valve, Fully Open
2
Gate Valve, Fully Open
0.15
Gate Valve, 1/4 Closed
0.26
Gate Valve, 1/2 Closed
2.1
Gate Valve, 3/4 Closed
17
Swing Check Valve, Forward Flow
2
Ball Valve, Fully Open
0.05
Ball Valve, 1/3 Closed
5.5
Ball Valve, 2/3 Closed
200
Diaphragm Valve, Open
2.3
Diaphragm Valve, Half Open
4.3
Diaphragm Valve, 1/4 Open
21
Water meter
7
K =(1 −A1/A2)2
The loss coefficient goes to zero as
A2 A1 .
The loss coefficient goes to one as A2
.
Minor Losses
Equivalent length
• LE/D
• fT
GEE Problem
Handout
References
Images & examples
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Mechanics of Fluids, 3rd Edition, Potter & Wiggert,
Brooks & Cole
Applied Fluid Mechanics, 6th Edition, Mott, Prentice Hall
Engineering Fluid Mechanics, 5th Edition Crowe, &
Roberson, Wiley
Fluid Mechanics Cengel & Cimbala McGraw Hill