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 = 10 L/sH = 73 m

A pump delivers 10 L/s of water (ρ = 1000 kg/m³) against a total head of 73 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 10 L/sH = 73 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
2.Easy
PQ = 10 L/sH = 68 m

A pump delivers 10 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 = 10 L/sH = 68 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 15 L/sH = 52 m

A pump delivers 15 L/s of water (ρ = 1000 kg/m³) against a head of 52 m. The pump efficiency is 75% 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 = 15 L/sH = 52 mηpump = 75%ηmotor = 90%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 60 L/sH = 54 m

In a test, a pump delivers 60 L/s of water (ρ = 1000 kg/m³) against a head of 54 m while its shaft takes 40.7 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 60 L/sH = 54 mPshaft = 40.7 kWg = 9.81 m/s²
η = %
5.Hard
400 kPa (gauge)PQ = 40 L/sΔz = 6 mL = 100 m, D = 200 mm, f = 0.025, ΣK = 5

A pump moves 40 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 200 mm and a Darcy friction factor f = 0.025; 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 = 40 L/sΔz = 6 mL = 100 mD = 200 mmf = 0.025ΣK = 5ptank = 400 kPa
H = m
6.Hard
PQ = 25 L/sΔz = 7 mL = 100 m, D = 150 mm, f = 0.025, ΣK = 5

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 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 = 5 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 25 L/sΔz = 7 mL = 100 mD = 150 mmf = 0.025ΣK = 5
H = m

Answer key

  1. 1. Ph = 7.161 kW
  2. 2. Ph = 6.671 kW
  3. 3. Pel = 11.34 kW
  4. 4. η = 78.09 %
  5. 5. H = 48.22 m
  6. 6. H = 9.21 m

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