Pumps & pump power worksheet with answers

Free printable Pumps & pump power worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
PQ = 60 L/sH = ?

A pump delivers 60 L/s of water (ρ = 1000 kg/m³) and gives it a hydraulic power of 2.2 kW. Use g = 9.81 m/s². Find the head H the pump adds.

Ph = 2.2 kWQ = 60 L/sρ = 1000 kg/m³g = 9.81 m/s²
H = m
2.Easy
PQ = 40 L/sH = 74 m

A pump delivers 40 L/s of water (ρ = 1000 kg/m³) against a total head of 74 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 40 L/sH = 74 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 15 L/sH = 22 m

A pump delivers 15 L/s of water (ρ = 1000 kg/m³) against a head of 22 m. The pump efficiency is 65% and the electric motor driving it has an efficiency of 90%. Use g = 9.81 m/s². Find the electrical power Pel the motor draws, in kW.

Q = 15 L/sH = 22 mηpump = 65%ηmotor = 90%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 20 L/sH = 80 m

In a test, a pump delivers 20 L/s of water (ρ = 1000 kg/m³) against a head of 80 m while its shaft takes 20.1 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 20 L/sH = 80 mPshaft = 20.1 kWg = 9.81 m/s²
η = %
5.Hard
PQ = 75 L/sΔz = 9 mL = 500 m, D = 200 mm, f = 0.015, ΣK = 5

A pump moves 75 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 9 m higher. The pipe is 500 m long with an inside diameter of 200 mm and a Darcy friction factor f = 0.015; the minor-loss coefficients add up to ΣK = 5 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 75%. Find the shaft power Pshaft in kW.

Q = 75 L/sΔz = 9 mL = 500 mD = 200 mmf = 0.015ΣK = 5η = 75%
Pshaft = kW
6.Hard
PQ = 50 L/sΔz = 6 mL = 500 m, D = 150 mm, f = 0.02, ΣK = 6

A pump moves 50 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 6 m higher. The pipe is 500 m long with an inside diameter of 150 mm and a Darcy friction factor f = 0.02; the minor-loss coefficients add up to ΣK = 6 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 78%. Find the shaft power Pshaft in kW.

Q = 50 L/sΔz = 6 mL = 500 mD = 150 mmf = 0.02ΣK = 6η = 78%
Pshaft = kW

Answer key

  1. 1. H = 3.738 m
  2. 2. Ph = 29.04 kW
  3. 3. Pel = 5.534 kW
  4. 4. η = 78.09 %
  5. 5. Pshaft = 20.94 kW
  6. 6. Pshaft = 22.42 kW

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