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 = 60 L/sH = ?

A pump delivers 60 L/s of water (ρ = 1000 kg/m³) and gives it a hydraulic power of 45 kW. Use g = 9.81 m/s². Find the head H the pump adds.

Ph = 45 kWQ = 60 L/sρ = 1000 kg/m³g = 9.81 m/s²
H = m
2.Easy
PQ = 20 L/sH = 43 m

A pump delivers 20 L/s of water (ρ = 1000 kg/m³) against a total head of 43 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 20 L/sH = 43 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 20 L/sH = 78 m

A pump with an efficiency of 80% delivers 20 L/s of water (ρ = 1000 kg/m³) against a head of 78 m. Use g = 9.81 m/s². Find the shaft power Pshaft needed, in kW.

Q = 20 L/sH = 78 mη = 80%g = 9.81 m/s²
Pshaft = kW
4.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 95%. Use g = 9.81 m/s². Find the electrical power Pel the motor draws, in kW.

Q = 10 L/sH = 58 mηpump = 65%ηmotor = 95%g = 9.81 m/s²
Pel = kW
5.Hard
PQ = 50 L/sΔz = 8 mL = 500 m, D = 200 mm, f = 0.02, ΣK = 8

A pump moves 50 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 500 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. The pump efficiency is 80%. Find the shaft power Pshaft in kW.

Q = 50 L/sΔz = 8 mL = 500 mD = 200 mmf = 0.02ΣK = 8η = 80%
Pshaft = kW
6.Hard
PQ = 80 L/sΔz = 18 mL = 100 m, D = 200 mm, f = 0.025, 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 18 m higher. The pipe is 100 m long with an inside diameter of 200 mm and a Darcy friction factor f = 0.025; 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 = 80 L/sΔz = 18 mL = 100 mD = 200 mmf = 0.025ΣK = 6
H = m

Answer key

  1. 1. H = 76.45 m
  2. 2. Ph = 8.437 kW
  3. 3. Pshaft = 19.13 kW
  4. 4. Pel = 9.214 kW
  5. 5. Pshaft = 9.496 kW
  6. 6. H = 24.11 m

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