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 = 8 L/sH = 71 m

A pump delivers 8 L/s of water (ρ = 1000 kg/m³) against a total head of 71 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 8 L/sH = 71 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
2.Easy
PQ = 5 L/sH = 25 m

A pump delivers 5 L/s of water (ρ = 1000 kg/m³) against a total head of 25 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 5 L/sH = 25 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 25 L/sH = 20 m

A pump with an efficiency of 70% delivers 25 L/s of water (ρ = 1000 kg/m³) against a head of 20 m. Use g = 9.81 m/s². Find the shaft power Pshaft needed, in kW.

Q = 25 L/sH = 20 mη = 70%g = 9.81 m/s²
Pshaft = kW
4.Medium
PQ = 100 L/sH = 60 m

In a test, a pump delivers 100 L/s of water (ρ = 1000 kg/m³) against a head of 60 m while its shaft takes 78.5 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 100 L/sH = 60 mPshaft = 78.5 kWg = 9.81 m/s²
η = %
5.Hard
PQ = 20 L/sΔz = 7 mL = 300 m, D = 150 mm, f = 0.018, ΣK = 8

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 7 m higher. The pipe is 300 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 pump efficiency is 82%. Find the shaft power Pshaft in kW.

Q = 20 L/sΔz = 7 mL = 300 mD = 150 mmf = 0.018ΣK = 8η = 82%
Pshaft = kW
6.Hard
PQ = 80 L/sΔz = 25 mL = 200 m, D = 200 mm, f = 0.02, ΣK = 6

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 25 m higher. The pipe is 200 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 = 6 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 82%. Find the shaft power Pshaft in kW.

Q = 80 L/sΔz = 25 mL = 200 mD = 200 mmf = 0.02ΣK = 6η = 82%
Pshaft = kW

Answer key

  1. 1. Ph = 5.572 kW
  2. 2. Ph = 1.226 kW
  3. 3. Pshaft = 7.007 kW
  4. 4. η = 74.98 %
  5. 5. Pshaft = 2.362 kW
  6. 6. Pshaft = 32.15 kW

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