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 = 100 L/sH = ?

A pump delivers 100 L/s of water (ρ = 1000 kg/m³) and gives it a hydraulic power of 4 kW. Use g = 9.81 m/s². Find the head H the pump adds.

Ph = 4 kWQ = 100 L/sρ = 1000 kg/m³g = 9.81 m/s²
H = m
2.Easy
PQ = 10 L/sH = 9 m

A pump delivers 10 L/s of water (ρ = 1000 kg/m³) against a total head of 9 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 10 L/sH = 9 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 60 L/sH = 66 m

In a test, a pump delivers 60 L/s of water (ρ = 1000 kg/m³) against a head of 66 m while its shaft takes 48.6 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 60 L/sH = 66 mPshaft = 48.6 kWg = 9.81 m/s²
η = %
4.Medium
PQ = 20 L/sH = 60 m

A pump delivers 20 L/s of water (ρ = 1000 kg/m³) against a head of 60 m. The pump efficiency is 78% and the electric motor driving it has an efficiency of 90%. Use g = 9.81 m/s². Find the electrical power Pel the motor draws, in kW.

Q = 20 L/sH = 60 mηpump = 78%ηmotor = 90%g = 9.81 m/s²
Pel = kW
5.Hard
PQ = 15 L/sΔz = 9 mL = 100 m, D = 100 mm, f = 0.015, ΣK = 4

A pump moves 15 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 9 m higher. The pipe is 100 m long with an inside diameter of 100 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 80%. Find the shaft power Pshaft in kW.

Q = 15 L/sΔz = 9 mL = 100 mD = 100 mmf = 0.015ΣK = 4η = 80%
Pshaft = kW
6.Hard
150 kPa (gauge)PQ = 50 L/sΔz = 12 mL = 150 m, D = 200 mm, f = 0.02, ΣK = 6

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 150 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 upper tank is closed and the air above its water is at a gauge pressure of 150 kPa. Find the head H the pump must add.

Q = 50 L/sΔz = 12 mL = 150 mD = 200 mmf = 0.02ΣK = 6ptank = 150 kPa
H = m

Answer key

  1. 1. H = 4.077 m
  2. 2. Ph = 0.8829 kW
  3. 3. η = 79.93 %
  4. 4. Pel = 16.77 kW
  5. 5. Pshaft = 2.305 kW
  6. 6. H = 30 m

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