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 = 1.2 m/sD = 100 mmν = 1.00 × 10⁻⁶ m²/s

Water at 20 °C (ν = 1.00 × 10⁻⁶ m²/s) flows at a mean velocity of 1.2 m/s through a pipe with an inside diameter of 100 mm. Find the Reynolds number Re.

V = 1.2 m/sD = 100 mmν = 1.00 × 10⁻⁶ m²/s
Re =
2.Easy
V = 0.5 m/sD = 100 mmρ = 891 kg/m³, μ = 0.29 Pa·s

SAE 30 motor oil (ρ = 891 kg/m³, μ = 0.29 Pa·s) flows at 0.5 m/s through a pipe with an inside diameter of 100 mm. Find the Reynolds number Re.

ρ = 891 kg/m³μ = 0.29 Pa·sV = 0.5 m/sD = 100 mm
Re =
3.Medium
Q = 200 L/sD = 300 mmL = 400 mf = 0.03

Water flows at 200 L/s through a pipe 400 m long with an inside diameter of 300 mm. Use the Darcy friction factor f = 0.03 and g = 9.81 m/s². Find the friction head loss hf.

Q = 200 L/sL = 400 mD = 300 mmf = 0.03g = 9.81 m/s²
hf = m
4.Medium
V = 1.2 m/sD = 75 mmL = 300 mf = 0.028

Water flows at a mean velocity of 1.2 m/s through a pipe 300 m long with an inside diameter of 75 mm. Use the Darcy friction factor f = 0.028 and g = 9.81 m/s². Find the friction head loss hf.

V = 1.2 m/sL = 300 mD = 75 mmf = 0.028g = 9.81 m/s²
hf = m
5.Hard
K = 10Δz = ?L = 150 m, D = 200 mm, f = 0.0152× bend (K = 0.3)

Two open reservoirs are joined by a pipe 150 m long with an inside diameter of 200 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 = 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 50 L/s?

Q = 50 L/sL = 150 mD = 200 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 10Kexit = 1.0
Δz = m
6.Hard
K = 5Δz = 17 mL = 500 m, D = 300 mm, f = 0.0183× bend (K = 0.3)

Two open reservoirs are joined by a pipe 500 m long with an inside diameter of 300 mm and a Darcy friction factor f = 0.018. The water surface of the upper reservoir is 17 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 = 17 mL = 500 mD = 300 mmf = 0.018Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 5Kexit = 1.0
Q = L/s

Answer key

  1. 1. Re = 120000
  2. 2. Re = 153.6
  3. 3. hf = 16.32 m
  4. 4. hf = 8.22 m
  5. 5. Δz = 3.015 m
  6. 6. Q = 211.1 L/s

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