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 = 2.1 m/sD = 75 mmν = 1.14 × 10⁻⁶ m²/s

Water at 15 °C (ν = 1.14 × 10⁻⁶ m²/s) flows at a mean velocity of 2.1 m/s through a pipe with an inside diameter of 75 mm. Find the Reynolds number Re.

V = 2.1 m/sD = 75 mmν = 1.14 × 10⁻⁶ m²/s
Re =
2.Easy
V = 0.75 m/sD = 200 mmρ = 850 kg/m³, μ = 0.005 Pa·s

Light fuel oil (ρ = 850 kg/m³, μ = 0.005 Pa·s) flows at 0.75 m/s through a pipe with an inside diameter of 200 mm. Find the Reynolds number Re.

ρ = 850 kg/m³μ = 0.005 Pa·sV = 0.75 m/sD = 200 mm
Re =
3.Medium
Q = 8 L/sD = 75 mmL = 150 mf = 0.022

Water flows at 8 L/s through a pipe 150 m long with an inside diameter of 75 mm. Use the Darcy friction factor f = 0.022 and g = 9.81 m/s². Find the friction head loss hf.

Q = 8 L/sL = 150 mD = 75 mmf = 0.022g = 9.81 m/s²
hf = m
4.Medium
V = 0.9 m/sD = 150 mmL = 400 mf = 0.03

Water flows at a mean velocity of 0.9 m/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.

V = 0.9 m/sL = 400 mD = 150 mmf = 0.03g = 9.81 m/s²
hf = m
5.Hard
K = 10Δz = ?L = 200 m, D = 250 mm, f = 0.0222× 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 = 0.022. 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 120 L/s?

Q = 120 L/sL = 200 mD = 250 mmf = 0.022Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 10Kexit = 1.0
Δz = m
6.Hard
K = 5Δz = 7 mL = 150 m, D = 200 mm, f = 0.023× 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 = 0.02. The water surface of the upper reservoir is 7 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 = 7 mL = 150 mD = 200 mmf = 0.02Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 5Kexit = 1.0
Q = L/s

Answer key

  1. 1. Re = 138158
  2. 2. Re = 25500
  3. 3. hf = 7.354 m
  4. 4. hf = 3.303 m
  5. 5. Δz = 9.046 m
  6. 6. Q = 77.79 L/s

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