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 = ?

A pump delivers 50 L/s of water (ρ = 1000 kg/m³) and gives it a hydraulic power of 4 kW. Use g = 9.81 m/s². Find the head H the pump adds.

Ph = 4 kWQ = 50 L/sρ = 1000 kg/m³g = 9.81 m/s²
H = m
2.Easy
PQ = 200 L/sH = 52 m

A pump delivers 200 L/s of water (ρ = 1000 kg/m³) against a total head of 52 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 200 L/sH = 52 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 15 L/sH = 38 m

A pump delivers 15 L/s of water (ρ = 1000 kg/m³) against a head of 38 m. The pump efficiency is 65% and the electric motor driving it has an efficiency of 94%. Use g = 9.81 m/s². Find the electrical power Pel the motor draws, in kW.

Q = 15 L/sH = 38 mηpump = 65%ηmotor = 94%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 50 L/sH = 16 m

In a test, a pump delivers 50 L/s of water (ρ = 1000 kg/m³) against a head of 16 m while its shaft takes 12.1 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 50 L/sH = 16 mPshaft = 12.1 kWg = 9.81 m/s²
η = %
5.Hard
300 kPa (gauge)PQ = 25 L/sΔz = 8 mL = 100 m, D = 150 mm, f = 0.025, 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 8 m higher. The pipe is 100 m long with an inside diameter of 150 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 = 25 L/sΔz = 8 mL = 100 mD = 150 mmf = 0.025ΣK = 8ptank = 300 kPa
H = m
6.Hard
100 kPa (gauge)PQ = 20 L/sΔz = 12 mL = 150 m, D = 100 mm, f = 0.022, ΣK = 6

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 12 m higher. The pipe is 150 m long with an inside diameter of 100 mm and a Darcy friction factor f = 0.022; the minor-loss coefficients add up to ΣK = 6 (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 100 kPa. Find the head H the pump must add.

Q = 20 L/sΔz = 12 mL = 150 mD = 100 mmf = 0.022ΣK = 6ptank = 100 kPa
H = m

Answer key

  1. 1. H = 8.155 m
  2. 2. Ph = 102 kW
  3. 3. Pel = 9.152 kW
  4. 4. η = 64.86 %
  5. 5. H = 41.1 m
  6. 6. H = 35.08 m

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