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 = 1.5 m/sD = 40 mmν = 1.14 × 10⁻⁶ m²/s

Water at 15 °C (ν = 1.14 × 10⁻⁶ m²/s) flows at a mean velocity of 1.5 m/s through a pipe with an inside diameter of 40 mm. Find the Reynolds number Re.

V = 1.5 m/sD = 40 mmν = 1.14 × 10⁻⁶ m²/s
Re =
2.Easy
Q = 6 L/sD = 50 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 50 mm at 6 L/s. Find the Reynolds number Re.

Q = 6 L/sD = 50 mmν = 0.801 × 10⁻⁶ m²/s
Re =
3.Medium
V = 3 m/sD = 200 mmL = 500 mf = 0.022

Water flows at a mean velocity of 3 m/s through a pipe 500 m long with an inside diameter of 200 mm. Use the Darcy friction factor f = 0.022 and g = 9.81 m/s². Find the friction head loss hf.

V = 3 m/sL = 500 mD = 200 mmf = 0.022g = 9.81 m/s²
hf = m
4.Medium
V = 1.5 m/sD = 100 mmL = 1000 mf = 0.015

Water flows at a mean velocity of 1.5 m/s through a pipe 1000 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.

V = 1.5 m/sL = 1000 mD = 100 mmf = 0.015g = 9.81 m/s²
hf = m
5.Hard
K = 5Δz = 5 mL = 150 m, D = 250 mm, f = 0.0183× 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 = 0.018. The water surface of the upper reservoir is 5 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 = 5 mL = 150 mD = 250 mmf = 0.018Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 5Kexit = 1.0
Q = L/s
6.Hard
K = 10Δz = ?L = 150 m, D = 300 mm, f = 0.022× bend (K = 0.3)

Two open reservoirs are joined by a pipe 150 m long with an inside diameter of 300 mm and a Darcy friction factor f = 0.02. 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 75 L/s?

Q = 75 L/sL = 150 mD = 300 mmf = 0.02Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 10Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 52632
  2. 2. Re = 190747
  3. 3. hf = 25.23 m
  4. 4. hf = 17.2 m
  5. 5. Q = 114 L/s
  6. 6. Δz = 1.268 m

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