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 = 50 L/sH = 73 m

A pump delivers 50 L/s of water (ρ = 1000 kg/m³) against a total head of 73 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 50 L/sH = 73 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
2.Easy
PQ = 15 L/sH = 6 m

A pump delivers 15 L/s of water (ρ = 1000 kg/m³) against a total head of 6 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 15 L/sH = 6 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 100 L/sH = 76 m

A pump delivers 100 L/s of water (ρ = 1000 kg/m³) against a head of 76 m. The pump efficiency is 75% and the electric motor driving it has an efficiency of 95%. Use g = 9.81 m/s². Find the electrical power Pel the motor draws, in kW.

Q = 100 L/sH = 76 mηpump = 75%ηmotor = 95%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 40 L/sH = 22 m

A pump delivers 40 L/s of water (ρ = 1000 kg/m³) against a head of 22 m. The pump efficiency is 70% 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 = 40 L/sH = 22 mηpump = 70%ηmotor = 90%g = 9.81 m/s²
Pel = kW
5.Hard
PQ = 75 L/sΔz = 10 mL = 300 m, D = 250 mm, f = 0.015, ΣK = 8

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 10 m higher. The pipe is 300 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.015; the minor-loss coefficients add up to ΣK = 8 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 85%. Find the shaft power Pshaft in kW.

Q = 75 L/sΔz = 10 mL = 300 mD = 250 mmf = 0.015ΣK = 8η = 85%
Pshaft = kW
6.Hard
PQ = 75 L/sΔz = 20 mL = 300 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 20 m higher. The pipe is 300 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. Find the head H the pump must add.

Q = 75 L/sΔz = 20 mL = 300 mD = 200 mmf = 0.015ΣK = 5
H = m

Answer key

  1. 1. Ph = 35.81 kW
  2. 2. Ph = 0.8829 kW
  3. 3. Pel = 104.6 kW
  4. 4. Pel = 13.7 kW
  5. 5. Pshaft = 11.33 kW
  6. 6. H = 27.99 m

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