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 = 0.5 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 0.5 m/s through a pipe with an inside diameter of 150 mm. Find the Reynolds number Re.

V = 0.5 m/sD = 150 mmν = 1.14 × 10⁻⁶ m²/s
Re =
2.Easy
V = 2 m/sD = 75 mmρ = 880 kg/m³, μ = 0.04 Pa·s

Hydraulic oil (ρ = 880 kg/m³, μ = 0.04 Pa·s) flows at 2 m/s through a pipe with an inside diameter of 75 mm. Find the Reynolds number Re.

ρ = 880 kg/m³μ = 0.04 Pa·sV = 2 m/sD = 75 mm
Re =
3.Medium
Q = 75 L/sD = 300 mmL = 400 mf = 0.025

Water flows at 75 L/s through a pipe 400 m long with an inside diameter of 300 mm. Use the Darcy friction factor f = 0.025 and g = 9.81 m/s². Find the friction head loss hf.

Q = 75 L/sL = 400 mD = 300 mmf = 0.025g = 9.81 m/s²
hf = m
4.Medium
Q = 80 L/sD = 200 mmL = 100 mf = 0.022

Water flows at 80 L/s through a pipe 100 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.

Q = 80 L/sL = 100 mD = 200 mmf = 0.022g = 9.81 m/s²
hf = m
5.Hard
K = 10free outletH = ?L = 100 m, D = 100 mm, f = 0.0254× bend (K = 0.3)

A pipe 100 m long with an inside diameter of 100 mm (Darcy friction factor f = 0.025) runs from an open reservoir and discharges as a free jet into the air. The minor losses are a square-edged entrance (K = 0.5), 4 bends (K = 0.3 each) and a valve (K = 10). Use g = 9.81 m/s². How far H must the reservoir surface be above the pipe outlet for a flow rate of 25 L/s?

Q = 25 L/sL = 100 mD = 100 mmf = 0.025Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 10
H = m
6.Hard
K = 2Δz = 18 mL = 150 m, D = 250 mm, f = 0.0184× 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 18 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 = 18 mL = 150 mD = 250 mmf = 0.018Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 2Kexit = 1.0
Q = L/s

Answer key

  1. 1. Re = 65789
  2. 2. Re = 3300
  3. 3. hf = 1.913 m
  4. 4. hf = 3.636 m
  5. 5. H = 19.47 m
  6. 6. Q = 234.3 L/s

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