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 = 10 L/sH = ?

A pump delivers 10 L/s of water (ρ = 1000 kg/m³) and gives it a hydraulic power of 3 kW. Use g = 9.81 m/s². Find the head H the pump adds.

Ph = 3 kWQ = 10 L/sρ = 1000 kg/m³g = 9.81 m/s²
H = m
2.Easy
PQ = 5 L/sH = 80 m

A pump delivers 5 L/s of water (ρ = 1000 kg/m³) against a total head of 80 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 5 L/sH = 80 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 10 L/sH = 52 m

A pump with an efficiency of 70% delivers 10 L/s of water (ρ = 1000 kg/m³) against a head of 52 m. Use g = 9.81 m/s². Find the shaft power Pshaft needed, in kW.

Q = 10 L/sH = 52 mη = 70%g = 9.81 m/s²
Pshaft = kW
4.Medium
PQ = 40 L/sH = 78 m

A pump with an efficiency of 65% delivers 40 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 = 40 L/sH = 78 mη = 65%g = 9.81 m/s²
Pshaft = kW
5.Hard
PQ = 120 L/sΔz = 11 mL = 600 m, D = 250 mm, f = 0.015, ΣK = 5

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 11 m higher. The pipe is 600 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.015; the minor-loss coefficients add up to ΣK = 5 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 72%. Find the shaft power Pshaft in kW.

Q = 120 L/sΔz = 11 mL = 600 mD = 250 mmf = 0.015ΣK = 5η = 72%
Pshaft = kW
6.Hard
300 kPa (gauge)PQ = 40 L/sΔz = 7 mL = 400 m, D = 150 mm, f = 0.018, ΣK = 8

A pump moves 40 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 7 m higher. The pipe is 400 m long with an inside diameter of 150 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 300 kPa. Find the head H the pump must add.

Q = 40 L/sΔz = 7 mL = 400 mD = 150 mmf = 0.018ΣK = 8ptank = 300 kPa
H = m

Answer key

  1. 1. H = 30.58 m
  2. 2. Ph = 3.924 kW
  3. 3. Pshaft = 7.287 kW
  4. 4. Pshaft = 47.09 kW
  5. 5. Pshaft = 38.4 kW
  6. 6. H = 52.2 m

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