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Energy
conservation(cont.)
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If energy is
added, removed or lost via pumps turbines, friction, etc.then we use
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Extended
Bernoulli’s Equation
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Example:
Determine the efficiency of the pump if the power input of the motor
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is
measured to be 1.5 hp. It is known
that the pump delivers 300 gal/min of water.
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No turbine work
and frictional losses, hence: hE=hL=0. Also z1=z2
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Given:
Q=300 gal/min=0.667 ft3/s=AV
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̃V1= Q/A1=3.33 ft/s V2=Q/A2=7.54
ft/s
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Looking at
the pressure term:
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Mercury
(gm=844.9 lb/ft3)
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water
(gw=62.4 lb/ft3)
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1 hp=550 lb-ft/s
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