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 = 1.25 m/sD = 50 mmρ = 880 kg/m³, μ = 0.04 Pa·s

Hydraulic oil (ρ = 880 kg/m³, μ = 0.04 Pa·s) flows at 1.25 m/s through a pipe with an inside diameter of 50 mm. Find the Reynolds number Re.

ρ = 880 kg/m³μ = 0.04 Pa·sV = 1.25 m/sD = 50 mm
Re =
2.Easy
V = 1.4 m/sD = 150 mmν = 1.00 × 10⁻⁶ m²/s

Water at 20 °C (ν = 1.00 × 10⁻⁶ m²/s) flows at a mean velocity of 1.4 m/s through a pipe with an inside diameter of 150 mm. Find the Reynolds number Re.

V = 1.4 m/sD = 150 mmν = 1.00 × 10⁻⁶ m²/s
Re =
3.Medium
V = 2.7 m/sD = 150 mmL = 200 mf = 0.02

Water flows at a mean velocity of 2.7 m/s through a pipe 200 m long with an inside diameter of 150 mm. Use the Darcy friction factor f = 0.02 and g = 9.81 m/s². Find the friction head loss hf.

V = 2.7 m/sL = 200 mD = 150 mmf = 0.02g = 9.81 m/s²
hf = m
4.Medium
Q = 25 L/sD = 250 mmL = 150 mf = 0.025

Water flows at 25 L/s through a pipe 150 m long with an inside diameter of 250 mm. Use the Darcy friction factor f = 0.025 and g = 9.81 m/s². Find the friction head loss hf.

Q = 25 L/sL = 150 mD = 250 mmf = 0.025g = 9.81 m/s²
hf = m
5.Hard
K = 2Δz = 39 mL = 300 m, D = 250 mm, f = 0.0254× 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 = 0.025. The water surface of the upper reservoir is 39 m above that of the lower one. The minor losses are a square-edged entrance (K = 0.5), 4 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 = 39 mL = 300 mD = 250 mmf = 0.025Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 2Kexit = 1.0
Q = L/s
6.Hard
K = 0.2Δz = ?L = 200 m, D = 250 mm, f = 0.0184× bend (K = 0.3)

Two open reservoirs are joined by a pipe 200 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.018. The minor losses are a square-edged entrance (K = 0.5), 4 bends (K = 0.3 each), a valve (K = 0.2) 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 = 200 mD = 250 mmf = 0.018Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 0.2Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 1375
  2. 2. Re = 210000
  3. 3. hf = 9.908 m
  4. 4. hf = 0.1983 m
  5. 5. Q = 230.5 L/s
  6. 6. Δz = 8.234 m

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