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 = 25 L/sH = ?

A pump delivers 25 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 = 25 L/sρ = 1000 kg/m³g = 9.81 m/s²
H = m
2.Easy
Δp = 250 kPaPQ = 8 L/s

A pump raises the pressure of 8 L/s of water by 250 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power Ph in kW.

Q = 8 L/sΔp = 250 kPa
Ph = kW
3.Medium
PQ = 10 L/sH = 58 m

A pump delivers 10 L/s of water (ρ = 1000 kg/m³) against a head of 58 m. The pump efficiency is 65% and the electric motor driving it has an efficiency of 94%. Use g = 9.81 m/s². Find the electrical power Pel the motor draws, in kW.

Q = 10 L/sH = 58 mηpump = 65%ηmotor = 94%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 80 L/sH = 20 m

A pump delivers 80 L/s of water (ρ = 1000 kg/m³) against a head of 20 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 = 80 L/sH = 20 mηpump = 82%ηmotor = 90%g = 9.81 m/s²
Pel = kW
5.Hard
300 kPa (gauge)PQ = 40 L/sΔz = 18 mL = 100 m, D = 150 mm, f = 0.018, ΣK = 8

A pump moves 40 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 18 m higher. The pipe is 100 m long with an inside diameter of 150 mm and a Darcy friction factor f = 0.018; the minor-loss coefficients add up to ΣK = 8 (entrance and exit included). Use g = 9.81 m/s². The upper tank is closed and the air above its water is at a gauge pressure of 300 kPa. Find the head H the pump must add.

Q = 40 L/sΔz = 18 mL = 100 mD = 150 mmf = 0.018ΣK = 8ptank = 300 kPa
H = m
6.Hard
PQ = 20 L/sΔz = 5 mL = 200 m, D = 150 mm, f = 0.015, ΣK = 6

A pump moves 20 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 5 m higher. The pipe is 200 m long with an inside diameter of 150 mm and a Darcy friction factor f = 0.015; the minor-loss coefficients add up to ΣK = 6 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 20 L/sΔz = 5 mL = 200 mD = 150 mmf = 0.015ΣK = 6
H = m

Answer key

  1. 1. H = 8.97 m
  2. 2. Ph = 2 kW
  3. 3. Pel = 9.312 kW
  4. 4. Pel = 21.27 kW
  5. 5. H = 53.8 m
  6. 6. H = 6.697 m

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