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 = 8 m

A pump delivers 20 L/s of water (ρ = 1000 kg/m³) against a total head of 8 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 20 L/sH = 8 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
2.Easy
Δp = 450 kPaPQ = 60 L/s

A pump raises the pressure of 60 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 = 60 L/sΔp = 450 kPa
Ph = kW
3.Medium
PQ = 30 L/sH = 50 m

A pump delivers 30 L/s of water (ρ = 1000 kg/m³) against a head of 50 m. The pump efficiency is 70% 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 = 30 L/sH = 50 mηpump = 70%ηmotor = 92%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 20 L/sH = 68 m

In a test, a pump delivers 20 L/s of water (ρ = 1000 kg/m³) against a head of 68 m while its shaft takes 22.2 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 20 L/sH = 68 mPshaft = 22.2 kWg = 9.81 m/s²
η = %
5.Hard
PQ = 80 L/sΔz = 6 mL = 500 m, D = 200 mm, f = 0.018, ΣK = 5

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 6 m higher. The pipe is 500 m long with an inside diameter of 200 mm and a Darcy friction factor f = 0.018; the minor-loss coefficients add up to ΣK = 5 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 85%. Find the shaft power Pshaft in kW.

Q = 80 L/sΔz = 6 mL = 500 mD = 200 mmf = 0.018ΣK = 5η = 85%
Pshaft = kW
6.Hard
PQ = 75 L/sΔz = 8 mL = 150 m, D = 250 mm, f = 0.02, 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 8 m higher. The pipe is 150 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 = 6 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 75 L/sΔz = 8 mL = 150 mD = 250 mmf = 0.02ΣK = 6
H = m

Answer key

  1. 1. Ph = 1.57 kW
  2. 2. Ph = 27 kW
  3. 3. Pel = 22.85 kW
  4. 4. η = 60.1 %
  5. 5. Pshaft = 20.8 kW
  6. 6. H = 10.14 m

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