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 = 22 m

A pump delivers 25 L/s of water (ρ = 1000 kg/m³) against a total head of 22 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 25 L/sH = 22 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
2.Easy
PQ = 30 L/sH = 73 m

A pump delivers 30 L/s of water (ρ = 1000 kg/m³) against a total head of 73 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 30 L/sH = 73 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 50 L/sH = 46 m

In a test, a pump delivers 50 L/s of water (ρ = 1000 kg/m³) against a head of 46 m while its shaft takes 34.7 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 50 L/sH = 46 mPshaft = 34.7 kWg = 9.81 m/s²
η = %
4.Medium
PQ = 50 L/sH = 44 m

A pump delivers 50 L/s of water (ρ = 1000 kg/m³) against a head of 44 m. The pump efficiency is 72% and the electric motor driving it has an efficiency of 88%. Use g = 9.81 m/s². Find the electrical power Pel the motor draws, in kW.

Q = 50 L/sH = 44 mηpump = 72%ηmotor = 88%g = 9.81 m/s²
Pel = kW
5.Hard
PQ = 50 L/sΔz = 14 mL = 200 m, D = 200 mm, f = 0.018, 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 14 m higher. The pipe is 200 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 = 8 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 50 L/sΔz = 14 mL = 200 mD = 200 mmf = 0.018ΣK = 8
H = m
6.Hard
PQ = 50 L/sΔz = 12 mL = 300 m, D = 150 mm, f = 0.015, ΣK = 4

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 12 m higher. The pipe is 300 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 = 4 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 75%. Find the shaft power Pshaft in kW.

Q = 50 L/sΔz = 12 mL = 300 mD = 150 mmf = 0.015ΣK = 4η = 75%
Pshaft = kW

Answer key

  1. 1. Ph = 5.396 kW
  2. 2. Ph = 21.48 kW
  3. 3. η = 65.02 %
  4. 4. Pel = 34.06 kW
  5. 5. H = 17.36 m
  6. 6. Pshaft = 16.92 kW

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