1. Fluid Mechanics LAB: Dynamic Pumps and Cavitation
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2. Dynamic Pumps
Kinetic or dynamic pumps add energy to the fluid by accelerating it through the action of a rotating impeller.
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3. Classification of dynamic pumps
Kinetic or dynamic
Pumps
Radial Flow
(Centrifugal)
Axial flow
(propeller)
Mixed flow
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4. Performance of Centrifugal Pumps
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5. System and Pump Operating Point
The operating point of the system is changed by flow control valve
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6. If below vapor pressure, cavitation occurs
Cavitation is the formation of vapor cavities due to the decrease of the suction pressure to a value below the vapor pressure.
If below vapor pressure, cavitation occurs
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7. Net Positive Suction Head
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8. Pump efficiency
The overall pump efficiency is a product of the volumetric efficiency and the mechanical efficiency
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9. Pump efficiency
(P is in Pa; QA and QT are in m3/s; T is in N-m; N is in Rev Per Second (RPS))
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10. Overall Efficiency = Vol.Efficiency x Mech.Efficiency
Pump efficiency
Overall Efficiency = Vol.Efficiency x Mech.Efficiency
Actual Power Out = P x QA
Actual Power In = Electrical Power Input (Watts)
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11. Suction Pressure (psig) Discharge Pressure (psig)
Trail No.
Flow Rate (GPM)
Suction Pressure (psig)
Discharge Pressure (psig)
Pressure Difference (psig)
Input Current (Amps)
Input Voltage (V) 1 2 3 4 5
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12. Suction Pressure (psig) Discharge Pressure (psig)
Trail No.
Frequency (Hz)
Flow Rate (GPM)
Suction Pressure (psig)
Discharge Pressure (psig)
Pressure Difference (psig) 1 15 2 20 3 25 4 30 5 35 6 40
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13. References Applied Fluid Mechanics, Robert L. Mott www.gewater.com
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