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 = 500 kPaPQ = 200 L/s

A pump raises the pressure of 200 L/s of water by 500 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power Ph in kW.

Q = 200 L/sΔp = 500 kPa
Ph = kW
2.Easy
PQ = 100 L/sH = 68 m

A pump delivers 100 L/s of water (ρ = 1000 kg/m³) against a total head of 68 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 100 L/sH = 68 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 40 L/sH = 80 m

In a test, a pump delivers 40 L/s of water (ρ = 1000 kg/m³) against a head of 80 m while its shaft takes 41.9 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 40 L/sH = 80 mPshaft = 41.9 kWg = 9.81 m/s²
η = %
4.Medium
PQ = 10 L/sH = 38 m

A pump delivers 10 L/s of water (ρ = 1000 kg/m³) against a head of 38 m. The pump efficiency is 70% and the electric motor driving it has an efficiency of 95%. Use g = 9.81 m/s². Find the electrical power Pel the motor draws, in kW.

Q = 10 L/sH = 38 mηpump = 70%ηmotor = 95%g = 9.81 m/s²
Pel = kW
5.Hard
PQ = 25 L/sΔz = 7 mL = 150 m, D = 150 mm, f = 0.015, ΣK = 8

A pump moves 25 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 7 m higher. The pipe is 150 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 = 8 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 25 L/sΔz = 7 mL = 150 mD = 150 mmf = 0.015ΣK = 8
H = m
6.Hard
PQ = 120 L/sΔz = 7 mL = 100 m, D = 250 mm, f = 0.025, ΣK = 2

A pump moves 120 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 7 m higher. The pipe is 100 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.025; the minor-loss coefficients add up to ΣK = 2 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 120 L/sΔz = 7 mL = 100 mD = 250 mmf = 0.025ΣK = 2
H = m

Answer key

  1. 1. Ph = 100 kW
  2. 2. Ph = 66.71 kW
  3. 3. η = 74.92 %
  4. 4. Pel = 5.606 kW
  5. 5. H = 9.346 m
  6. 6. H = 10.66 m

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