CE 356 Elements of Hydraulic Engineering

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CE 356 Elements of Hydraulic Engineering

• Dr. Ben R. Hodges
• University of Texas at Austin
• Pumps

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centrifugal pumps
Radial flow centrifugal pumps
fluid enters at the central axis, then
accelerates perpendicular to the axis
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acceleration
impeller
Spinning the flow adds velocity.
Why does the exit diameter slowly increase around
the impeller?
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axial and mixed flow
Axial flow pumps accelerate the flow directly
across the axis (i.e. a fan or propeller)
Mixed flow are a combination of radial and axial
flow
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efficiency contours
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system curve
So the system curve must be a quadratic increase
in head loss with increasing discharge
jargon
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selection
Pump selection diagram
impeller speed
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selection
Figure 15.15
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NPSH
How high can a pump suck?