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 = 100 L/sH = 57 m

A pump delivers 100 L/s of water (ρ = 1000 kg/m³) against a total head of 57 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 100 L/sH = 57 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
2.Easy
PQ = 200 L/sH = 12 m

A pump delivers 200 L/s of water (ρ = 1000 kg/m³) against a total head of 12 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 200 L/sH = 12 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 40 L/sH = 42 m

In a test, a pump delivers 40 L/s of water (ρ = 1000 kg/m³) against a head of 42 m while its shaft takes 20.6 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 40 L/sH = 42 mPshaft = 20.6 kWg = 9.81 m/s²
η = %
4.Medium
PQ = 30 L/sH = 46 m

A pump delivers 30 L/s of water (ρ = 1000 kg/m³) against a head of 46 m. The pump efficiency is 78% 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 = 30 L/sH = 46 mηpump = 78%ηmotor = 95%g = 9.81 m/s²
Pel = kW
5.Hard
400 kPa (gauge)PQ = 120 L/sΔz = 18 mL = 150 m, D = 250 mm, f = 0.022, 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 18 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. 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 = 120 L/sΔz = 18 mL = 150 mD = 250 mmf = 0.022ΣK = 8ptank = 400 kPa
H = m
6.Hard
400 kPa (gauge)PQ = 120 L/sΔz = 5 mL = 200 m, D = 250 mm, f = 0.02, ΣK = 2.5

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 5 m higher. The pipe is 200 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.02; the minor-loss coefficients add up to ΣK = 2.5 (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 = 120 L/sΔz = 5 mL = 200 mD = 250 mmf = 0.02ΣK = 2.5ptank = 400 kPa
H = m

Answer key

  1. 1. Ph = 55.92 kW
  2. 2. Ph = 23.54 kW
  3. 3. η = 80 %
  4. 4. Pel = 18.27 kW
  5. 5. H = 65.23 m
  6. 6. H = 51.41 m

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