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 = 1.5 m/sD = 100 mmν = 0.801 × 10⁻⁶ m²/s

Water at 30 °C (ν = 0.801 × 10⁻⁶ m²/s) flows at a mean velocity of 1.5 m/s through a pipe with an inside diameter of 100 mm. Find the Reynolds number Re.

V = 1.5 m/sD = 100 mmν = 0.801 × 10⁻⁶ m²/s
Re =
2.Easy
V = 2.1 m/sD = 40 mmν = 1.14 × 10⁻⁶ m²/s

Water at 15 °C (ν = 1.14 × 10⁻⁶ m²/s) flows at a mean velocity of 2.1 m/s through a pipe with an inside diameter of 40 mm. Find the Reynolds number Re.

V = 2.1 m/sD = 40 mmν = 1.14 × 10⁻⁶ m²/s
Re =
3.Medium
Q = 100 L/sD = 300 mmL = 150 mf = 0.018

Water flows at 100 L/s through a pipe 150 m long with an inside diameter of 300 mm. Use the Darcy friction factor f = 0.018 and g = 9.81 m/s². Find the friction head loss hf.

Q = 100 L/sL = 150 mD = 300 mmf = 0.018g = 9.81 m/s²
hf = m
4.Medium
V = 1.7 m/sD = 250 mmL = 400 mf = 0.022

Water (ρ = 1000 kg/m³) flows at 1.7 m/s through a horizontal pipe, 400 m long, with an inside diameter of 250 mm. Use the Darcy friction factor f = 0.022 and g = 9.81 m/s². Find the pressure drop Δp over the pipe in kPa.

V = 1.7 m/sL = 400 mD = 250 mmf = 0.022ρ = 1000 kg/m³
Δp = kPa
5.Hard
K = 10Δz = ?L = 100 m, D = 100 mm, f = 0.024× bend (K = 0.3)

Two open reservoirs are joined by a pipe 100 m long with an inside diameter of 100 mm and a Darcy friction factor f = 0.02. The minor losses are a square-edged entrance (K = 0.5), 4 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. What difference in water level Δz between the reservoirs gives a flow rate of 12 L/s?

Q = 12 L/sL = 100 mD = 100 mmf = 0.02Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 10Kexit = 1.0
Δz = m
6.Hard
K = 5Δz = 25 mL = 200 m, D = 200 mm, f = 0.022× bend (K = 0.3)

Two open reservoirs are joined by a pipe 200 m long with an inside diameter of 200 mm and a Darcy friction factor f = 0.02. The water surface of the upper reservoir is 25 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 = 5) 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 = 25 mL = 200 mD = 200 mmf = 0.02Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 5Kexit = 1.0
Q = L/s

Answer key

  1. 1. Re = 187266
  2. 2. Re = 73684
  3. 3. hf = 0.9181 m
  4. 4. Δp = 50.86 kPa
  5. 5. Δz = 3.891 m
  6. 6. Q = 133.7 L/s

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