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 = 25 mmρ = 850 kg/m³, μ = 0.005 Pa·s

Light fuel oil (ρ = 850 kg/m³, μ = 0.005 Pa·s) flows at 3 m/s through a pipe with an inside diameter of 25 mm. Find the Reynolds number Re.

ρ = 850 kg/m³μ = 0.005 Pa·sV = 3 m/sD = 25 mm
Re =
2.Easy
V = 3 m/sD = 100 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 100 mm. Find the Reynolds number Re.

V = 3 m/sD = 100 mmν = 1.14 × 10⁻⁶ m²/s
Re =
3.Medium
Q = 30 L/sD = 150 mmL = 400 mf = 0.03

Water flows at 30 L/s through a pipe 400 m long with an inside diameter of 150 mm. Use the Darcy friction factor f = 0.03 and g = 9.81 m/s². Find the friction head loss hf.

Q = 30 L/sL = 400 mD = 150 mmf = 0.03g = 9.81 m/s²
hf = m
4.Medium
Q = 12 L/sD = 100 mmL = 150 mf = 0.015

Water flows at 12 L/s through a pipe 150 m long with an inside diameter of 100 mm. Use the Darcy friction factor f = 0.015 and g = 9.81 m/s². Find the friction head loss hf.

Q = 12 L/sL = 150 mD = 100 mmf = 0.015g = 9.81 m/s²
hf = m
5.Hard
K = 10Δz = 18 mL = 100 m, D = 150 mm, f = 0.0182× bend (K = 0.3)

Two open reservoirs are joined by a pipe 100 m long with an inside diameter of 150 mm and a Darcy friction factor f = 0.018. The water surface of the upper reservoir is 18 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 = 18 mL = 100 mD = 150 mmf = 0.018Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 10Kexit = 1.0
Q = L/s
6.Hard
K = 10Δz = ?L = 150 m, D = 250 mm, f = 0.0253× 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 = 0.025. The minor losses are a square-edged entrance (K = 0.5), 3 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 75 L/s?

Q = 75 L/sL = 150 mD = 250 mmf = 0.025Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 10Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 12750
  2. 2. Re = 263158
  3. 3. hf = 11.75 m
  4. 4. hf = 2.677 m
  5. 5. Q = 67.65 L/s
  6. 6. Δz = 3.26 m

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