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 = 2.75 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 2.75 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 = 2.75 m/sD = 50 mm
Re =
2.Easy
V = 1.9 m/sD = 50 mmν = 1.14 × 10⁻⁶ m²/s

Water at 15 °C (ν = 1.14 × 10⁻⁶ m²/s) flows at a mean velocity of 1.9 m/s through a pipe with an inside diameter of 50 mm. Find the Reynolds number Re.

V = 1.9 m/sD = 50 mmν = 1.14 × 10⁻⁶ m²/s
Re =
3.Medium
Q = 6 L/sD = 50 mmL = 100 mf = 0.018

Water flows at 6 L/s through a pipe 100 m long with an inside diameter of 50 mm. Use the Darcy friction factor f = 0.018 and g = 9.81 m/s². Find the friction head loss hf.

Q = 6 L/sL = 100 mD = 50 mmf = 0.018g = 9.81 m/s²
hf = m
4.Medium
Q = 100 L/sD = 300 mmL = 400 mf = 0.018

Water flows at 100 L/s through a pipe 400 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 = 400 mD = 300 mmf = 0.018g = 9.81 m/s²
hf = m
5.Hard
K = 5free outletH = ?L = 400 m, D = 200 mm, f = 0.0152× bend (K = 0.3)

A pipe 400 m long with an inside diameter of 200 mm (Darcy friction factor f = 0.015) runs from an open reservoir and discharges as a free jet into the air. The minor losses are a square-edged entrance (K = 0.5), 2 bends (K = 0.3 each) and a valve (K = 5). Use g = 9.81 m/s². How far H must the reservoir surface be above the pipe outlet for a flow rate of 75 L/s?

Q = 75 L/sL = 400 mD = 200 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 5
H = m
6.Hard
K = 2Δz = 13 mL = 400 m, D = 300 mm, f = 0.0153× bend (K = 0.3)

Two open reservoirs are joined by a pipe 400 m long with an inside diameter of 300 mm and a Darcy friction factor f = 0.015. The water surface of the upper reservoir is 13 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 = 2) 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 = 13 mL = 400 mD = 300 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 2Kexit = 1.0
Q = L/s

Answer key

  1. 1. Re = 422.5
  2. 2. Re = 83333
  3. 3. hf = 17.13 m
  4. 4. hf = 2.448 m
  5. 5. H = 10.78 m
  6. 6. Q = 228.5 L/s

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