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 = 30 L/s

A pump raises the pressure of 30 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 = 30 L/sΔp = 150 kPa
Ph = kW
2.Easy
PQ = 30 L/sH = 80 m

A pump delivers 30 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 = 30 L/sH = 80 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 20 L/sH = 30 m

A pump with an efficiency of 65% delivers 20 L/s of water (ρ = 1000 kg/m³) against a head of 30 m. Use g = 9.81 m/s². Find the shaft power Pshaft needed, in kW.

Q = 20 L/sH = 30 mη = 65%g = 9.81 m/s²
Pshaft = kW
4.Medium
PQ = 30 L/sH = 40 m

In a test, a pump delivers 30 L/s of water (ρ = 1000 kg/m³) against a head of 40 m while its shaft takes 16.4 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 30 L/sH = 40 mPshaft = 16.4 kWg = 9.81 m/s²
η = %
5.Hard
PQ = 75 L/sΔz = 5 mL = 150 m, D = 200 mm, f = 0.015, ΣK = 2

A pump moves 75 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 5 m higher. The pipe is 150 m long with an inside diameter of 200 mm and a Darcy friction factor f = 0.015; the minor-loss coefficients add up to ΣK = 2 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 75 L/sΔz = 5 mL = 150 mD = 200 mmf = 0.015ΣK = 2
H = m
6.Hard
PQ = 120 L/sΔz = 8 mL = 600 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 8 m higher. The pipe is 600 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. Find the head H the pump must add.

Q = 120 L/sΔz = 8 mL = 600 mD = 250 mmf = 0.02ΣK = 4
H = m

Answer key

  1. 1. Ph = 4.5 kW
  2. 2. Ph = 23.54 kW
  3. 3. Pshaft = 9.055 kW
  4. 4. η = 71.78 %
  5. 5. H = 8.849 m
  6. 6. H = 23.84 m

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