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 = 400 kPaPQ = 10 L/s

A pump raises the pressure of 10 L/s of water by 400 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power Ph in kW.

Q = 10 L/sΔp = 400 kPa
Ph = kW
2.Easy
Δp = 500 kPaPQ = 30 L/s

A pump raises the pressure of 30 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 = 30 L/sΔp = 500 kPa
Ph = kW
3.Medium
PQ = 10 L/sH = 56 m

A pump delivers 10 L/s of water (ρ = 1000 kg/m³) against a head of 56 m. The pump efficiency is 60% 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 = 10 L/sH = 56 mηpump = 60%ηmotor = 94%g = 9.81 m/s²
Pel = kW
4.Medium
PQ = 50 L/sH = 34 m

A pump with an efficiency of 75% delivers 50 L/s of water (ρ = 1000 kg/m³) against a head of 34 m. Use g = 9.81 m/s². Find the shaft power Pshaft needed, in kW.

Q = 50 L/sH = 34 mη = 75%g = 9.81 m/s²
Pshaft = kW
5.Hard
PQ = 100 L/sΔz = 12 mL = 150 m, D = 250 mm, f = 0.025, ΣK = 4

A pump moves 100 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 250 mm and a Darcy friction factor f = 0.025; the minor-loss coefficients add up to ΣK = 4 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 75%. Find the shaft power Pshaft in kW.

Q = 100 L/sΔz = 12 mL = 150 mD = 250 mmf = 0.025ΣK = 4η = 75%
Pshaft = kW
6.Hard
PQ = 20 L/sΔz = 6 mL = 150 m, D = 100 mm, f = 0.015, 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 6 m higher. The pipe is 150 m long with an inside diameter of 100 mm and a Darcy friction factor f = 0.015; 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 = 6 mL = 150 mD = 100 mmf = 0.015ΣK = 6
H = m

Answer key

  1. 1. Ph = 4 kW
  2. 2. Ph = 15 kW
  3. 3. Pel = 9.74 kW
  4. 4. Pshaft = 22.24 kW
  5. 5. Pshaft = 20.95 kW
  6. 6. H = 15.42 m

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