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 = 3 m/sD = 50 mmρ = 891 kg/m³, μ = 0.29 Pa·s

SAE 30 motor oil (ρ = 891 kg/m³, μ = 0.29 Pa·s) flows at 3 m/s through a pipe with an inside diameter of 50 mm. Find the Reynolds number Re.

ρ = 891 kg/m³μ = 0.29 Pa·sV = 3 m/sD = 50 mm
Re =
2.Easy
V = 3 m/sD = 200 mmν = 1.14 × 10⁻⁶ m²/s

Water at 15 °C (ν = 1.14 × 10⁻⁶ m²/s) flows at a mean velocity of 3 m/s through a pipe with an inside diameter of 200 mm. Find the Reynolds number Re.

V = 3 m/sD = 200 mmν = 1.14 × 10⁻⁶ m²/s
Re =
3.Medium
V = 1.7 m/sD = 250 mmL = 100 mf = 0.015

Water (ρ = 1000 kg/m³) flows at 1.7 m/s through a horizontal pipe, 100 m long, with an inside diameter of 250 mm. Use the Darcy friction factor f = 0.015 and g = 9.81 m/s². Find the pressure drop Δp over the pipe in kPa.

V = 1.7 m/sL = 100 mD = 250 mmf = 0.015ρ = 1000 kg/m³
Δp = kPa
4.Medium
Q = 20 L/sD = 100 mmL = 200 mf = 0.025

Water flows at 20 L/s through a pipe 200 m long with an inside diameter of 100 mm. Use the Darcy friction factor f = 0.025 and g = 9.81 m/s². Find the friction head loss hf.

Q = 20 L/sL = 200 mD = 100 mmf = 0.025g = 9.81 m/s²
hf = m
5.Hard
K = 5Δz = ?L = 300 m, D = 250 mm, f = 0.0223× bend (K = 0.3)

Two open reservoirs are joined by a pipe 300 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.022. The minor losses are a square-edged entrance (K = 0.5), 3 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 150 L/s?

Q = 150 L/sL = 300 mD = 250 mmf = 0.022Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 5Kexit = 1.0
Δz = m
6.Hard
K = 5Δz = 33 mL = 200 m, D = 100 mm, f = 0.0153× bend (K = 0.3)

Two open reservoirs are joined by a pipe 200 m long with an inside diameter of 100 mm and a Darcy friction factor f = 0.015. The water surface of the upper reservoir is 33 m above that of the lower one. The minor losses are a square-edged entrance (K = 0.5), 3 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 = 33 mL = 200 mD = 100 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 5Kexit = 1.0
Q = L/s

Answer key

  1. 1. Re = 460.9
  2. 2. Re = 526316
  3. 3. Δp = 8.67 kPa
  4. 4. hf = 16.53 m
  5. 5. Δz = 16.09 m
  6. 6. Q = 32.68 L/s

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