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 = 150 L/s

A pump raises the pressure of 150 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 = 150 L/sΔp = 500 kPa
Ph = kW
2.Easy
Δp = 650 kPaPQ = 10 L/s

A pump raises the pressure of 10 L/s of water by 650 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 = 650 kPa
Ph = kW
3.Medium
PQ = 100 L/sH = 54 m

A pump delivers 100 L/s of water (ρ = 1000 kg/m³) against a head of 54 m. The pump efficiency is 65% 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 = 100 L/sH = 54 mηpump = 65%ηmotor = 92%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 20 L/sH = 72 m

A pump delivers 20 L/s of water (ρ = 1000 kg/m³) against a head of 72 m. The pump efficiency is 82% and the electric motor driving it has an efficiency of 88%. Use g = 9.81 m/s². Find the electrical power Pel the motor draws, in kW.

Q = 20 L/sH = 72 mηpump = 82%ηmotor = 88%g = 9.81 m/s²
Pel = kW
5.Hard
PQ = 100 L/sΔz = 28 mL = 150 m, D = 250 mm, f = 0.022, ΣK = 8

A pump moves 100 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 28 m higher. The pipe is 150 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.022; 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 = 100 L/sΔz = 28 mL = 150 mD = 250 mmf = 0.022ΣK = 8
H = m
6.Hard
400 kPa (gauge)PQ = 20 L/sΔz = 25 mL = 100 m, D = 100 mm, f = 0.025, ΣK = 8

A pump moves 20 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 25 m higher. The pipe is 100 m long with an inside diameter of 100 mm and a Darcy friction factor f = 0.025; the minor-loss coefficients add up to ΣK = 8 (entrance and exit included). Use g = 9.81 m/s². The upper tank is closed and the air above its water is at a gauge pressure of 400 kPa. Find the head H the pump must add.

Q = 20 L/sΔz = 25 mL = 100 mD = 100 mmf = 0.025ΣK = 8ptank = 400 kPa
H = m

Answer key

  1. 1. Ph = 75 kW
  2. 2. Ph = 6.5 kW
  3. 3. Pel = 88.59 kW
  4. 4. Pel = 19.58 kW
  5. 5. H = 32.48 m
  6. 6. H = 76.68 m

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