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 = 40 L/sH = 74 m

A pump delivers 40 L/s of water (ρ = 1000 kg/m³) against a total head of 74 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 40 L/sH = 74 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
2.Easy
Δp = 700 kPaPQ = 15 L/s

A pump raises the pressure of 15 L/s of water by 700 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power Ph in kW.

Q = 15 L/sΔp = 700 kPa
Ph = kW
3.Medium
PQ = 50 L/sH = 80 m

In a test, a pump delivers 50 L/s of water (ρ = 1000 kg/m³) against a head of 80 m while its shaft takes 60.4 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

Q = 50 L/sH = 80 mPshaft = 60.4 kWg = 9.81 m/s²
η = %
4.Medium
PQ = 150 L/sH = 36 m

A pump with an efficiency of 72% delivers 150 L/s of water (ρ = 1000 kg/m³) against a head of 36 m. Use g = 9.81 m/s². Find the shaft power Pshaft needed, in kW.

Q = 150 L/sH = 36 mη = 72%g = 9.81 m/s²
Pshaft = kW
5.Hard
PQ = 120 L/sΔz = 25 mL = 200 m, D = 250 mm, f = 0.018, ΣK = 6

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 25 m higher. The pipe is 200 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.018; the minor-loss coefficients add up to ΣK = 6 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 85%. Find the shaft power Pshaft in kW.

Q = 120 L/sΔz = 25 mL = 200 mD = 250 mmf = 0.018ΣK = 6η = 85%
Pshaft = kW
6.Hard
200 kPa (gauge)PQ = 120 L/sΔz = 17 mL = 500 m, D = 250 mm, f = 0.018, ΣK = 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 17 m higher. The pipe is 500 m long with an inside diameter of 250 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 200 kPa. Find the head H the pump must add.

Q = 120 L/sΔz = 17 mL = 500 mD = 250 mmf = 0.018ΣK = 5ptank = 200 kPa
H = m

Answer key

  1. 1. Ph = 29.04 kW
  2. 2. Ph = 10.5 kW
  3. 3. η = 64.97 %
  4. 4. Pshaft = 73.58 kW
  5. 5. Pshaft = 43.23 kW
  6. 6. H = 49.88 m

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