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 = 5 L/sH = 27 m

A pump delivers 5 L/s of water (ρ = 1000 kg/m³) against a total head of 27 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 5 L/sH = 27 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
2.Easy
PQ = 40 L/sH = 5 m

A pump delivers 40 L/s of water (ρ = 1000 kg/m³) against a total head of 5 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 40 L/sH = 5 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 50 L/sH = 10 m

A pump delivers 50 L/s of water (ρ = 1000 kg/m³) against a head of 10 m. The pump efficiency is 70% and the electric motor driving it has an efficiency of 92%. Use g = 9.81 m/s². Find the electrical power Pel the motor draws, in kW.

Q = 50 L/sH = 10 mηpump = 70%ηmotor = 92%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 60 L/sH = 62 m

In a test, a pump delivers 60 L/s of water (ρ = 1000 kg/m³) against a head of 62 m while its shaft takes 48.7 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 60 L/sH = 62 mPshaft = 48.7 kWg = 9.81 m/s²
η = %
5.Hard
PQ = 80 L/sΔz = 16 mL = 200 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 16 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 = 8 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 80 L/sΔz = 16 mL = 200 mD = 200 mmf = 0.02ΣK = 8
H = m
6.Hard
PQ = 75 L/sΔz = 23 mL = 100 m, D = 200 mm, f = 0.022, ΣK = 5

A pump moves 75 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 23 m higher. The pipe is 100 m long with an inside diameter of 200 mm and a Darcy friction factor f = 0.022; the minor-loss coefficients add up to ΣK = 5 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 75%. Find the shaft power Pshaft in kW.

Q = 75 L/sΔz = 23 mL = 100 mD = 200 mmf = 0.022ΣK = 5η = 75%
Pshaft = kW

Answer key

  1. 1. Ph = 1.324 kW
  2. 2. Ph = 1.962 kW
  3. 3. Pel = 7.616 kW
  4. 4. η = 74.93 %
  5. 5. H = 25.25 m
  6. 6. Pshaft = 27.12 kW

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