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 = 100 kPaPQ = 10 L/s

A pump raises the pressure of 10 L/s of water by 100 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 = 100 kPa
Ph = kW
2.Easy
PQ = 60 L/sH = 44 m

A pump delivers 60 L/s of water (ρ = 1000 kg/m³) against a total head of 44 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 60 L/sH = 44 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 80 L/sH = 30 m

A pump delivers 80 L/s of water (ρ = 1000 kg/m³) against a head of 30 m. The pump efficiency is 72% 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 = 80 L/sH = 30 mηpump = 72%ηmotor = 92%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 25 L/sH = 66 m

A pump delivers 25 L/s of water (ρ = 1000 kg/m³) against a head of 66 m. The pump efficiency is 72% and the electric motor driving it has an efficiency of 90%. Use g = 9.81 m/s². Find the electrical power Pel the motor draws, in kW.

Q = 25 L/sH = 66 mηpump = 72%ηmotor = 90%g = 9.81 m/s²
Pel = kW
5.Hard
PQ = 50 L/sΔz = 9 mL = 600 m, D = 150 mm, f = 0.015, ΣK = 5

A pump moves 50 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 9 m higher. The pipe is 600 m long with an inside diameter of 150 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 82%. Find the shaft power Pshaft in kW.

Q = 50 L/sΔz = 9 mL = 600 mD = 150 mmf = 0.015ΣK = 5η = 82%
Pshaft = kW
6.Hard
PQ = 80 L/sΔz = 9 mL = 200 m, D = 200 mm, f = 0.015, ΣK = 8

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 9 m higher. The pipe is 200 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 = 8 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 80 L/sΔz = 9 mL = 200 mD = 200 mmf = 0.015ΣK = 8
H = m

Answer key

  1. 1. Ph = 1 kW
  2. 2. Ph = 25.9 kW
  3. 3. Pel = 35.54 kW
  4. 4. Pel = 24.98 kW
  5. 5. Pshaft = 21.25 kW
  6. 6. H = 16.6 m

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