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 = 250 kPaPQ = 40 L/s

A pump raises the pressure of 40 L/s of water by 250 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power Ph in kW.

Q = 40 L/sΔp = 250 kPa
Ph = kW
2.Easy
Δp = 400 kPaPQ = 8 L/s

A pump raises the pressure of 8 L/s of water by 400 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power Ph in kW.

Q = 8 L/sΔp = 400 kPa
Ph = kW
3.Medium
PQ = 100 L/sH = 44 m

A pump delivers 100 L/s of water (ρ = 1000 kg/m³) against a head of 44 m. The pump efficiency is 78% 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 = 100 L/sH = 44 mηpump = 78%ηmotor = 90%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 30 L/sH = 30 m

A pump delivers 30 L/s of water (ρ = 1000 kg/m³) against a head of 30 m. The pump efficiency is 75% 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 = 30 L/sH = 30 mηpump = 75%ηmotor = 90%g = 9.81 m/s²
Pel = kW
5.Hard
PQ = 60 L/sΔz = 6 mL = 500 m, D = 250 mm, f = 0.015, ΣK = 8

A pump moves 60 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 250 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 = 60 L/sΔz = 6 mL = 500 mD = 250 mmf = 0.015ΣK = 8
H = m
6.Hard
PQ = 75 L/sΔz = 12 mL = 200 m, D = 200 mm, f = 0.02, ΣK = 4

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 200 m long with an inside diameter of 200 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. The pump efficiency is 82%. Find the shaft power Pshaft in kW.

Q = 75 L/sΔz = 12 mL = 200 mD = 200 mmf = 0.02ΣK = 4η = 82%
Pshaft = kW

Answer key

  1. 1. Ph = 10 kW
  2. 2. Ph = 3.2 kW
  3. 3. Pel = 61.49 kW
  4. 4. Pel = 13.08 kW
  5. 5. H = 8.894 m
  6. 6. Pshaft = 17.02 kW

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