ENTC-303 PROF. ALVARADO 1

Fluid Mechanics LAB:Dynamic Pumps and Cavitation

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ENTC-303 PROF. ALVARADO 2

Dynamic Pumps

Kinetic or dynamic pumps add energy to the fluid by accelerating it through the action of a rotating impeller.

PROF. ALVARADO 3

Classification of dynamic pumps

Kinetic or dynamic Pumps

Radial Flow(Centrifugal)

Axial flow(propeller)

Mixed flow

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PROF. ALVARADO 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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PROF. ALVARADO 6

CavitationCavitation 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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ENTC-370 PROF. ALVARADO 7

Net Positive Suction Head

vpfsspAvailable hhhhNPSH

Pump efficiency • The overall pump efficiency is a product of

the volumetric efficiency and the mechanical efficiency

PROF. ALVARADO 8ENTC-303

 

(P is in Pa; QA and QT are in m3/s; T is in N-m; N is in Rev Per Second (RPS))

9

Pump efficiency

%100T

A

QQ

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Pump efficiency

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Overall Efficiency = Vol.Efficiency x Mech.Efficiency

Actual Power Out = P x QA

Actual Power In = Electrical Power Input (Watts)

PROF. ALVARADO 11

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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PROF. ALVARADO 12

Trail No. Frequency (Hz)

Flow Rate (GPM)

Suction Pressure

(psig)

Discharge Pressure

(psig)

Pressure Difference

(psig)

115

220

325

430

535

640

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PROF. ALVARADO 13

References

• Applied Fluid Mechanics, Robert L. Mott• www.gewater.com• www.pumpworld.com

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