Pipe friction & head loss worksheet with answers

Free printable Pipe friction & head loss 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
V = 1.3 m/sD = 25 mmν = 1.31 × 10⁻⁶ m²/s

Water at 10 °C (ν = 1.31 × 10⁻⁶ m²/s) flows at a mean velocity of 1.3 m/s through a pipe with an inside diameter of 25 mm. Find the Reynolds number Re.

V = 1.3 m/sD = 25 mmν = 1.31 × 10⁻⁶ m²/s
Re =
2.Easy
Q = 40 L/sD = 150 mmν = 0.801 × 10⁻⁶ m²/s

Water at 30 °C (ν = 0.801 × 10⁻⁶ m²/s) flows through a pipe with an inside diameter of 150 mm at 40 L/s. Find the Reynolds number Re.

Q = 40 L/sD = 150 mmν = 0.801 × 10⁻⁶ m²/s
Re =
3.Medium
V = 2.5 m/sD = 50 mmL = 300 mf = 0.02

Water (ρ = 1000 kg/m³) flows at 2.5 m/s through a horizontal pipe, 300 m long, with an inside diameter of 50 mm. Use the Darcy friction factor f = 0.02 and g = 9.81 m/s². Find the pressure drop Δp over the pipe in kPa.

V = 2.5 m/sL = 300 mD = 50 mmf = 0.02ρ = 1000 kg/m³
Δp = kPa
4.Medium
V = 2.8 m/sD = 150 mmL = 100 mf = 0.025

Water flows at a mean velocity of 2.8 m/s through a pipe 100 m long with an inside diameter of 150 mm. Use the Darcy friction factor f = 0.025 and g = 9.81 m/s². Find the friction head loss hf.

V = 2.8 m/sL = 100 mD = 150 mmf = 0.025g = 9.81 m/s²
hf = m
5.Hard
K = 10Δz = 20 mL = 150 m, D = 250 mm, f = 0.0152× bend (K = 0.3)

Two open reservoirs are joined by a pipe 150 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.015. The water surface of the upper reservoir is 20 m above that of the lower one. The minor losses are a square-edged entrance (K = 0.5), 2 bends (K = 0.3 each), a valve (K = 10) and the exit into the lower reservoir (K = 1.0). Use g = 9.81 m/s². Find the flow rate Q in L/s.

Δz = 20 mL = 150 mD = 250 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 10Kexit = 1.0
Q = L/s
6.Hard
K = 5Δz = ?L = 600 m, D = 300 mm, f = 0.0152× bend (K = 0.3)

Two open reservoirs are joined by a pipe 600 m long with an inside diameter of 300 mm and a Darcy friction factor f = 0.015. The minor losses are a square-edged entrance (K = 0.5), 2 bends (K = 0.3 each), a valve (K = 5) and the exit into the lower reservoir (K = 1.0). Use g = 9.81 m/s². What difference in water level Δz between the reservoirs gives a flow rate of 200 L/s?

Q = 200 L/sL = 600 mD = 300 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 5Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 24809
  2. 2. Re = 423883
  3. 3. Δp = 375 kPa
  4. 4. hf = 6.66 m
  5. 5. Q = 211.7 L/s
  6. 6. Δz = 15.14 m

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