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 = 450 kPaPQ = 8 L/s

A pump raises the pressure of 8 L/s of water by 450 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power Ph in kW.

Q = 8 L/sΔp = 450 kPa
Ph = kW
2.Easy
PQ = 12 L/sH = 56 m

A pump delivers 12 L/s of water (ρ = 1000 kg/m³) against a total head of 56 m. Use g = 9.81 m/s². Find the hydraulic power Ph given to the water, in kW.

Q = 12 L/sH = 56 mρ = 1000 kg/m³g = 9.81 m/s²
Ph = kW
3.Medium
PQ = 15 L/sH = 72 m

A pump with an efficiency of 65% delivers 15 L/s of water (ρ = 1000 kg/m³) against a head of 72 m. Use g = 9.81 m/s². Find the shaft power Pshaft needed, in kW.

Q = 15 L/sH = 72 mη = 65%g = 9.81 m/s²
Pshaft = kW
4.Medium
PQ = 80 L/sH = 30 m

A pump delivers 80 L/s of water (ρ = 1000 kg/m³) against a head of 30 m. The pump efficiency is 72% 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 = 80 L/sH = 30 mηpump = 72%ηmotor = 95%g = 9.81 m/s²
Pel = kW
5.Hard
PQ = 80 L/sΔz = 7 mL = 100 m, D = 200 mm, f = 0.022, ΣK = 5

A pump moves 80 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 200 mm and a Darcy friction factor f = 0.022; 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 = 80 L/sΔz = 7 mL = 100 mD = 200 mmf = 0.022ΣK = 5
H = m
6.Hard
PQ = 50 L/sΔz = 22 mL = 100 m, D = 150 mm, f = 0.022, ΣK = 4

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 22 m higher. The pipe is 100 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 = 4 (entrance and exit included). Use g = 9.81 m/s². Find the head H the pump must add.

Q = 50 L/sΔz = 22 mL = 100 mD = 150 mmf = 0.022ΣK = 4
H = m

Answer key

  1. 1. Ph = 3.6 kW
  2. 2. Ph = 6.592 kW
  3. 3. Pshaft = 16.3 kW
  4. 4. Pel = 34.42 kW
  5. 5. H = 12.29 m
  6. 6. H = 29.62 m

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