1. CE 356 Elements of Hydraulic Engineering
Dr. Ben R. Hodges
University of Texas at Austin
Pumps

2. Radial flow centrifugal pumps
fluid enters at the central axis, then accelerates perpendicular to the axis
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3. Spinning the flow adds velocity.
acceleration
impeller
Spinning the flow adds velocity.
Why does the exit diameter slowly increase around the impeller?
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4. Mixed flow are a combination of radial and axial flow
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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5. efficiency contours
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6. system curve
So the system curve must be a quadratic increase in head loss with increasing discharge
jargon
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7. Possible operating points
selection
Pump selection diagram
shaft hp
impeller diameter
efficiency contours
System curve
impeller speed
Possible operating points
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8. selection
Figure 15.15
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9. NPSH
How high can a pump suck?
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