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 = 60 L/sH = ?

A pump delivers 60 L/s of water (ρ = 1000 kg/m³) and gives it a hydraulic power of 22 kW. Use g = 9.81 m/s². Find the head H the pump adds.

Ph = 22 kWQ = 60 L/sρ = 1000 kg/m³g = 9.81 m/s²
H = m
2.Easy
PQ = 30 L/sH = 27 m

A pump delivers 30 L/s of water (ρ = 1000 kg/m³) against a total head of 27 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 30 L/sH = 27 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.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 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 = 30 L/sH = 30 mηpump = 78%ηmotor = 90%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 60 L/sH = 44 m

A pump delivers 60 L/s of water (ρ = 1000 kg/m³) against a head of 44 m. The pump efficiency is 72% 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 = 60 L/sH = 44 mηpump = 72%ηmotor = 95%g = 9.81 m/s²
Pel = kW
5.Hard
250 kPa (gauge)PQ = 120 L/sΔz = 6 mL = 100 m, D = 250 mm, f = 0.025, ΣK = 8

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 6 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 = 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 250 kPa. Find the head H the pump must add.

Q = 120 L/sΔz = 6 mL = 100 mD = 250 mmf = 0.025ΣK = 8ptank = 250 kPa
H = m
6.Hard
400 kPa (gauge)PQ = 15 L/sΔz = 10 mL = 150 m, D = 100 mm, f = 0.018, ΣK = 5

A pump moves 15 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 10 m higher. The pipe is 150 m long with an inside diameter of 100 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 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 = 15 L/sΔz = 10 mL = 150 mD = 100 mmf = 0.018ΣK = 5ptank = 400 kPa
H = m

Answer key

  1. 1. H = 37.38 m
  2. 2. Ph = 7.946 kW
  3. 3. Pel = 12.58 kW
  4. 4. Pel = 37.86 kW
  5. 5. H = 36.97 m
  6. 6. H = 56.72 m

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