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 = 20 L/sH = 48 m

A pump delivers 20 L/s of water (ρ = 1000 kg/m³) against a total head of 48 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 20 L/sH = 48 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
2.Easy
PQ = 75 L/sH = 26 m

A pump delivers 75 L/s of water (ρ = 1000 kg/m³) against a total head of 26 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 75 L/sH = 26 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 150 L/sH = 60 m

A pump with an efficiency of 78% delivers 150 L/s of water (ρ = 1000 kg/m³) against a head of 60 m. Use g = 9.81 m/s². Find the shaft power Pshaft needed, in kW.

Q = 150 L/sH = 60 mη = 78%g = 9.81 m/s²
Pshaft = 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 56.1 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 60 L/sH = 62 mPshaft = 56.1 kWg = 9.81 m/s²
η = %
5.Hard
PQ = 120 L/sΔz = 20 mL = 150 m, D = 250 mm, f = 0.015, ΣK = 6

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 20 m higher. The pipe is 150 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 = 6 (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 = 20 mL = 150 mD = 250 mmf = 0.015ΣK = 6η = 82%
Pshaft = kW
6.Hard
150 kPa (gauge)PQ = 30 L/sΔz = 6 mL = 200 m, D = 150 mm, f = 0.018, ΣK = 6

A pump moves 30 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 6 m higher. The pipe is 200 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 = 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 = 30 L/sΔz = 6 mL = 200 mD = 150 mmf = 0.018ΣK = 6ptank = 150 kPa
H = m

Answer key

  1. 1. Ph = 9.418 kW
  2. 2. Ph = 19.13 kW
  3. 3. Pshaft = 113.2 kW
  4. 4. η = 65.05 %
  5. 5. Pshaft = 35.27 kW
  6. 6. H = 25.7 m

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