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 = 450 kPaPQ = 10 L/s

A pump raises the pressure of 10 L/s of water by 450 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power Ph in kW.

Q = 10 L/sΔp = 450 kPa
Ph = kW
2.Easy
Δp = 800 kPaPQ = 100 L/s

A pump raises the pressure of 100 L/s of water by 800 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 = 800 kPa
Ph = kW
3.Medium
PQ = 30 L/sH = 24 m

In a test, a pump delivers 30 L/s of water (ρ = 1000 kg/m³) against a head of 24 m while its shaft takes 8.3 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 30 L/sH = 24 mPshaft = 8.3 kWg = 9.81 m/s²
η = %
4.Medium
PQ = 15 L/sH = 68 m

A pump delivers 15 L/s of water (ρ = 1000 kg/m³) against a head of 68 m. The pump efficiency is 65% 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 = 15 L/sH = 68 mηpump = 65%ηmotor = 92%g = 9.81 m/s²
Pel = kW
5.Hard
PQ = 75 L/sΔz = 12 mL = 400 m, D = 200 mm, f = 0.015, ΣK = 6

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 12 m higher. The pipe is 400 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 = 6 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 75 L/sΔz = 12 mL = 400 mD = 200 mmf = 0.015ΣK = 6
H = m
6.Hard
PQ = 80 L/sΔz = 25 mL = 300 m, D = 200 mm, f = 0.015, ΣK = 6

A pump moves 80 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 25 m higher. The pipe is 300 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 = 6 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 80 L/sΔz = 25 mL = 300 mD = 200 mmf = 0.015ΣK = 6
H = m

Answer key

  1. 1. Ph = 4.5 kW
  2. 2. Ph = 80 kW
  3. 3. η = 85.1 %
  4. 4. Pel = 16.73 kW
  5. 5. H = 22.46 m
  6. 6. H = 34.42 m

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