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 = 50 L/sH = 48 m

A pump delivers 50 L/s of water (ρ = 1000 kg/m³) against a total head of 48 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 50 L/sH = 48 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
2.Easy
Δp = 400 kPaPQ = 50 L/s

A pump raises the pressure of 50 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 = 50 L/sΔp = 400 kPa
Ph = kW
3.Medium
PQ = 80 L/sH = 24 m

A pump delivers 80 L/s of water (ρ = 1000 kg/m³) against a head of 24 m. The pump efficiency is 85% 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 = 80 L/sH = 24 mηpump = 85%ηmotor = 90%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 40 L/sH = 24 m

In a test, a pump delivers 40 L/s of water (ρ = 1000 kg/m³) against a head of 24 m while its shaft takes 11.1 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 40 L/sH = 24 mPshaft = 11.1 kWg = 9.81 m/s²
η = %
5.Hard
PQ = 50 L/sΔz = 13 mL = 500 m, D = 150 mm, f = 0.018, 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 13 m higher. The pipe is 500 m long with an inside diameter of 150 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 70%. Find the shaft power Pshaft in kW.

Q = 50 L/sΔz = 13 mL = 500 mD = 150 mmf = 0.018ΣK = 5η = 70%
Pshaft = kW
6.Hard
PQ = 75 L/sΔz = 8 mL = 150 m, D = 250 mm, f = 0.015, ΣK = 5

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 = 0.015; the minor-loss coefficients add up to ΣK = 5 (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 = 0.015ΣK = 5
H = m

Answer key

  1. 1. Ph = 23.54 kW
  2. 2. Ph = 20 kW
  3. 3. Pel = 24.62 kW
  4. 4. η = 84.84 %
  5. 5. Pshaft = 27.69 kW
  6. 6. H = 9.666 m

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