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
Δp = 150 kPaPQ = 100 L/s

A pump raises the pressure of 100 L/s of water by 150 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power Ph in kW.

Q = 100 L/sΔp = 150 kPa
Ph = kW
2.Easy
PQ = 50 L/sH = ?

A pump delivers 50 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 = 50 L/sρ = 1000 kg/m³g = 9.81 m/s²
H = m
3.Medium
PQ = 25 L/sH = 12 m

A pump with an efficiency of 65% delivers 25 L/s of water (ρ = 1000 kg/m³) against a head of 12 m. Use g = 9.81 m/s². Find the shaft power Pshaft needed, in kW.

Q = 25 L/sH = 12 mη = 65%g = 9.81 m/s²
Pshaft = kW
4.Medium
PQ = 150 L/sH = 66 m

In a test, a pump delivers 150 L/s of water (ρ = 1000 kg/m³) against a head of 66 m while its shaft takes 149.4 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 150 L/sH = 66 mPshaft = 149.4 kWg = 9.81 m/s²
η = %
5.Hard
PQ = 100 L/sΔz = 6 mL = 200 m, D = 250 mm, f = 0.015, ΣK = 5

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 6 m higher. The pipe is 200 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 = 100 L/sΔz = 6 mL = 200 mD = 250 mmf = 0.015ΣK = 5η = 72%
Pshaft = kW
6.Hard
400 kPa (gauge)PQ = 20 L/sΔz = 15 mL = 150 m, D = 100 mm, f = 0.02, ΣK = 5

A pump moves 20 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 15 m higher. The pipe is 150 m long with an inside diameter of 100 mm and a Darcy friction factor f = 0.02; the minor-loss coefficients add up to ΣK = 5 (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 400 kPa. Find the head H the pump must add.

Q = 20 L/sΔz = 15 mL = 150 mD = 100 mmf = 0.02ΣK = 5ptank = 400 kPa
H = m

Answer key

  1. 1. Ph = 15 kW
  2. 2. H = 8.155 m
  3. 3. Pshaft = 4.528 kW
  4. 4. η = 65.01 %
  5. 5. Pshaft = 13.07 kW
  6. 6. H = 67.34 m

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