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 = 550 kPaPQ = 75 L/s

A pump raises the pressure of 75 L/s of water by 550 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power Ph in kW.

Q = 75 L/sΔp = 550 kPa
Ph = kW
2.Easy
PQ = 150 L/sH = 68 m

A pump delivers 150 L/s of water (ρ = 1000 kg/m³) against a total head of 68 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 150 L/sH = 68 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 15 L/sH = 48 m

A pump with an efficiency of 80% delivers 15 L/s of water (ρ = 1000 kg/m³) against a head of 48 m. Use g = 9.81 m/s². Find the shaft power Pshaft needed, in kW.

Q = 15 L/sH = 48 mη = 80%g = 9.81 m/s²
Pshaft = kW
4.Medium
PQ = 20 L/sH = 74 m

A pump with an efficiency of 70% delivers 20 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 = 20 L/sH = 74 mη = 70%g = 9.81 m/s²
Pshaft = kW
5.Hard
PQ = 12 L/sΔz = 13 mL = 100 m, D = 100 mm, f = 0.025, ΣK = 8

A pump moves 12 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 13 m higher. The pipe is 100 m long with an inside diameter of 100 mm and a Darcy friction factor f = 0.025; the minor-loss coefficients add up to ΣK = 8 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 82%. Find the shaft power Pshaft in kW.

Q = 12 L/sΔz = 13 mL = 100 mD = 100 mmf = 0.025ΣK = 8η = 82%
Pshaft = kW
6.Hard
PQ = 80 L/sΔz = 15 mL = 100 m, D = 200 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 15 m higher. The pipe is 100 m long with an inside diameter of 200 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 = 15 mL = 100 mD = 200 mmf = 0.018ΣK = 4
H = m

Answer key

  1. 1. Ph = 41.25 kW
  2. 2. Ph = 100.1 kW
  3. 3. Pshaft = 8.829 kW
  4. 4. Pshaft = 20.74 kW
  5. 5. Pshaft = 2.43 kW
  6. 6. H = 19.3 m

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