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
Q = 4 L/sD = 75 mmν = 0.801 × 10⁻⁶ m²/s

Water at 30 °C (ν = 0.801 × 10⁻⁶ m²/s) flows through a pipe with an inside diameter of 75 mm at 4 L/s. Find the Reynolds number Re.

Q = 4 L/sD = 75 mmν = 0.801 × 10⁻⁶ m²/s
Re =
2.Easy
V = 0.3 m/sD = 150 mmν = 1.14 × 10⁻⁶ m²/s

Water at 15 °C (ν = 1.14 × 10⁻⁶ m²/s) flows at a mean velocity of 0.3 m/s through a pipe with an inside diameter of 150 mm. Find the Reynolds number Re.

V = 0.3 m/sD = 150 mmν = 1.14 × 10⁻⁶ m²/s
Re =
3.Medium
V = 0.8 m/sD = 300 mmL = 50 mf = 0.015

Water flows at a mean velocity of 0.8 m/s through a pipe 50 m long with an inside diameter of 300 mm. Use the Darcy friction factor f = 0.015 and g = 9.81 m/s². Find the friction head loss hf.

V = 0.8 m/sL = 50 mD = 300 mmf = 0.015g = 9.81 m/s²
hf = m
4.Medium
V = 1.8 m/sD = 50 mmL = 1000 mf = 0.015

Water flows at a mean velocity of 1.8 m/s through a pipe 1000 m long with an inside diameter of 50 mm. Use the Darcy friction factor f = 0.015 and g = 9.81 m/s². Find the friction head loss hf.

V = 1.8 m/sL = 1000 mD = 50 mmf = 0.015g = 9.81 m/s²
hf = m
5.Hard
K = 0.2Δz = 15 mL = 100 m, D = 250 mm, f = 0.0184× bend (K = 0.3)

Two open reservoirs are joined by a pipe 100 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.018. The water surface of the upper reservoir is 15 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 = 0.2) 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 = 15 mL = 100 mD = 250 mmf = 0.018Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 0.2Kexit = 1.0
Q = L/s
6.Hard
K = 2Δz = ?L = 100 m, D = 250 mm, f = 0.0153× bend (K = 0.3)

Two open reservoirs are joined by a pipe 100 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.015. 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. What difference in water level Δz between the reservoirs gives a flow rate of 50 L/s?

Q = 50 L/sL = 100 mD = 250 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 2Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 84777
  2. 2. Re = 39474
  3. 3. hf = 0.08155 m
  4. 4. hf = 49.54 m
  5. 5. Q = 265 L/s
  6. 6. Δz = 0.55 m

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