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 = 5 L/sH = 55 m

A pump delivers 5 L/s of water (ρ = 1000 kg/m³) against a total head of 55 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 5 L/sH = 55 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
2.Easy
PQ = 30 L/sH = 46 m

A pump delivers 30 L/s of water (ρ = 1000 kg/m³) against a total head of 46 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 30 L/sH = 46 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 25 L/sH = 62 m

A pump with an efficiency of 65% delivers 25 L/s of water (ρ = 1000 kg/m³) against a head of 62 m. Use g = 9.81 m/s². Find the shaft power Pshaft needed, in kW.

Q = 25 L/sH = 62 mη = 65%g = 9.81 m/s²
Pshaft = kW
4.Medium
PQ = 20 L/sH = 58 m

A pump delivers 20 L/s of water (ρ = 1000 kg/m³) against a head of 58 m. The pump efficiency is 82% 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 = 20 L/sH = 58 mηpump = 82%ηmotor = 90%g = 9.81 m/s²
Pel = kW
5.Hard
PQ = 80 L/sΔz = 9 mL = 100 m, D = 200 mm, f = 0.022, ΣK = 2.5

A pump moves 80 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 100 m long with an inside diameter of 200 mm and a Darcy friction factor f = 0.022; the minor-loss coefficients add up to ΣK = 2.5 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 80 L/sΔz = 9 mL = 100 mD = 200 mmf = 0.022ΣK = 2.5
H = m
6.Hard
PQ = 80 L/sΔz = 6 mL = 300 m, D = 250 mm, f = 0.015, ΣK = 4

A pump moves 80 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 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 = 4 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 80 L/sΔz = 6 mL = 300 mD = 250 mmf = 0.015ΣK = 4
H = m

Answer key

  1. 1. Ph = 2.698 kW
  2. 2. Ph = 13.54 kW
  3. 3. Pshaft = 23.39 kW
  4. 4. Pel = 15.42 kW
  5. 5. H = 13.46 m
  6. 6. H = 8.978 m

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