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
Δp = 650 kPaPQ = 10 L/s

A pump raises the pressure of 10 L/s of water by 650 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power Ph in kW.

Q = 10 L/sΔp = 650 kPa
Ph = kW
2.Easy
PQ = 15 L/sH = ?

A pump delivers 15 L/s of water (ρ = 1000 kg/m³) and gives it a hydraulic power of 3 kW. Use g = 9.81 m/s². Find the head H the pump adds.

Ph = 3 kWQ = 15 L/sρ = 1000 kg/m³g = 9.81 m/s²
H = m
3.Medium
PQ = 10 L/sH = 72 m

A pump delivers 10 L/s of water (ρ = 1000 kg/m³) against a head of 72 m. The pump efficiency is 80% 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 = 10 L/sH = 72 mηpump = 80%ηmotor = 90%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 10 L/sH = 74 m

A pump with an efficiency of 85% delivers 10 L/s of water (ρ = 1000 kg/m³) against a head of 74 m. Use g = 9.81 m/s². Find the shaft power Pshaft needed, in kW.

Q = 10 L/sH = 74 mη = 85%g = 9.81 m/s²
Pshaft = kW
5.Hard
PQ = 80 L/sΔz = 8 mL = 100 m, D = 250 mm, f = 0.018, 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 8 m higher. The pipe is 100 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.018; 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 = 8 mL = 100 mD = 250 mmf = 0.018ΣK = 4
H = m
6.Hard
PQ = 80 L/sΔz = 34 mL = 300 m, D = 200 mm, f = 0.02, ΣK = 8

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 34 m higher. The pipe is 300 m long with an inside diameter of 200 mm and a Darcy friction factor f = 0.02; the minor-loss coefficients add up to ΣK = 8 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 80 L/sΔz = 34 mL = 300 mD = 200 mmf = 0.02ΣK = 8
H = m

Answer key

  1. 1. Ph = 6.5 kW
  2. 2. H = 20.39 m
  3. 3. Pel = 9.81 kW
  4. 4. Pshaft = 8.54 kW
  5. 5. H = 9.516 m
  6. 6. H = 46.56 m

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