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 = 500 kPaPQ = 75 L/s

A pump raises the pressure of 75 L/s of water by 500 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power Ph in kW.

Q = 75 L/sΔp = 500 kPa
Ph = kW
2.Easy
PQ = 10 L/sH = 8 m

A pump delivers 10 L/s of water (ρ = 1000 kg/m³) against a total head of 8 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 10 L/sH = 8 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 50 L/sH = 52 m

In a test, a pump delivers 50 L/s of water (ρ = 1000 kg/m³) against a head of 52 m while its shaft takes 31.1 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 50 L/sH = 52 mPshaft = 31.1 kWg = 9.81 m/s²
η = %
4.Medium
PQ = 15 L/sH = 70 m

In a test, a pump delivers 15 L/s of water (ρ = 1000 kg/m³) against a head of 70 m while its shaft takes 12.1 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 15 L/sH = 70 mPshaft = 12.1 kWg = 9.81 m/s²
η = %
5.Hard
350 kPa (gauge)PQ = 50 L/sΔz = 13 mL = 300 m, D = 150 mm, f = 0.022, ΣK = 6

A pump moves 50 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 13 m higher. The pipe is 300 m long with an inside diameter of 150 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 350 kPa. Find the head H the pump must add.

Q = 50 L/sΔz = 13 mL = 300 mD = 150 mmf = 0.022ΣK = 6ptank = 350 kPa
H = m
6.Hard
PQ = 20 L/sΔz = 11 mL = 200 m, D = 100 mm, f = 0.02, 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 11 m higher. The pipe is 200 m long with an inside diameter of 100 mm and a Darcy friction factor f = 0.02; the minor-loss coefficients add up to ΣK = 6 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 20 L/sΔz = 11 mL = 200 mD = 100 mmf = 0.02ΣK = 6
H = m

Answer key

  1. 1. Ph = 37.5 kW
  2. 2. Ph = 0.7848 kW
  3. 3. η = 82.01 %
  4. 4. η = 85.13 %
  5. 5. H = 69.08 m
  6. 6. H = 26.2 m

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