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 = 76 m

A pump delivers 100 L/s of water (ρ = 1000 kg/m³) against a total head of 76 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 100 L/sH = 76 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
2.Easy
PQ = 5 L/sH = ?

A pump delivers 5 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 = 5 L/sρ = 1000 kg/m³g = 9.81 m/s²
H = m
3.Medium
PQ = 30 L/sH = 44 m

A pump delivers 30 L/s of water (ρ = 1000 kg/m³) against a head of 44 m. The pump efficiency is 65% and the electric motor driving it has an efficiency of 94%. Use g = 9.81 m/s². Find the electrical power Pel the motor draws, in kW.

Q = 30 L/sH = 44 mηpump = 65%ηmotor = 94%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 25 L/sH = 28 m

A pump delivers 25 L/s of water (ρ = 1000 kg/m³) against a head of 28 m. The pump efficiency is 82% 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 = 25 L/sH = 28 mηpump = 82%ηmotor = 92%g = 9.81 m/s²
Pel = kW
5.Hard
350 kPa (gauge)PQ = 100 L/sΔz = 24 mL = 150 m, D = 250 mm, f = 0.018, ΣK = 8

A pump moves 100 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 24 m higher. The pipe is 150 m long with an inside diameter of 250 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 upper tank is closed and the air above its water is at a gauge pressure of 350 kPa. Find the head H the pump must add.

Q = 100 L/sΔz = 24 mL = 150 mD = 250 mmf = 0.018ΣK = 8ptank = 350 kPa
H = m
6.Hard
PQ = 120 L/sΔz = 9 mL = 150 m, D = 250 mm, f = 0.02, ΣK = 4

A pump moves 120 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 150 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.02; the minor-loss coefficients add up to ΣK = 4 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 82%. Find the shaft power Pshaft in kW.

Q = 120 L/sΔz = 9 mL = 150 mD = 250 mmf = 0.02ΣK = 4η = 82%
Pshaft = kW

Answer key

  1. 1. Ph = 74.56 kW
  2. 2. H = 81.55 m
  3. 3. Pel = 21.19 kW
  4. 4. Pel = 9.103 kW
  5. 5. H = 63.65 m
  6. 6. Pshaft = 19.92 kW

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