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 = 150 kPaPQ = 60 L/s

A pump raises the pressure of 60 L/s of water by 150 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power Ph in kW.

Q = 60 L/sΔp = 150 kPa
Ph = kW
2.Easy
PQ = 10 L/sH = 80 m

A pump delivers 10 L/s of water (ρ = 1000 kg/m³) against a total head of 80 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 10 L/sH = 80 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 10 L/sH = 46 m

A pump delivers 10 L/s of water (ρ = 1000 kg/m³) against a head of 46 m. The pump efficiency is 75% 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 = 10 L/sH = 46 mηpump = 75%ηmotor = 88%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 150 L/sH = 28 m

A pump delivers 150 L/s of water (ρ = 1000 kg/m³) against a head of 28 m. The pump efficiency is 72% 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 = 150 L/sH = 28 mηpump = 72%ηmotor = 88%g = 9.81 m/s²
Pel = kW
5.Hard
300 kPa (gauge)PQ = 20 L/sΔz = 19 mL = 150 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 19 m higher. The pipe is 150 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 300 kPa. Find the head H the pump must add.

Q = 20 L/sΔz = 19 mL = 150 mD = 100 mmf = 0.025ΣK = 8ptank = 300 kPa
H = m
6.Hard
PQ = 80 L/sΔz = 37 mL = 300 m, D = 200 mm, f = 0.022, 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 37 m higher. The pipe is 300 m long with an inside diameter of 200 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 = 80 L/sΔz = 37 mL = 300 mD = 200 mmf = 0.022ΣK = 8
H = m

Answer key

  1. 1. Ph = 9 kW
  2. 2. Ph = 7.848 kW
  3. 3. Pel = 6.837 kW
  4. 4. Pel = 65.03 kW
  5. 5. H = 64.62 m
  6. 6. H = 50.55 m

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