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 = 1.75 m/sD = 75 mmρ = 891 kg/m³, μ = 0.29 Pa·s

SAE 30 motor oil (ρ = 891 kg/m³, μ = 0.29 Pa·s) flows at 1.75 m/s through a pipe with an inside diameter of 75 mm. Find the Reynolds number Re.

ρ = 891 kg/m³μ = 0.29 Pa·sV = 1.75 m/sD = 75 mm
Re =
2.Easy
V = 1.5 m/sD = 200 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 200 mm. Find the Reynolds number Re.

V = 1.5 m/sD = 200 mmν = 1.14 × 10⁻⁶ m²/s
Re =
3.Medium
Q = 20 L/sD = 150 mmL = 100 mf = 0.015

Water flows at 20 L/s through a pipe 100 m long with an inside diameter of 150 mm. Use the Darcy friction factor f = 0.015 and g = 9.81 m/s². Find the friction head loss hf.

Q = 20 L/sL = 100 mD = 150 mmf = 0.015g = 9.81 m/s²
hf = m
4.Medium
Q = 60 L/sD = 150 mmL = 200 mf = 0.028

Water flows at 60 L/s through a pipe 200 m long with an inside diameter of 150 mm. Use the Darcy friction factor f = 0.028 and g = 9.81 m/s². Find the friction head loss hf.

Q = 60 L/sL = 200 mD = 150 mmf = 0.028g = 9.81 m/s²
hf = m
5.Hard
K = 5free outletH = ?L = 100 m, D = 150 mm, f = 0.0153× bend (K = 0.3)

A pipe 100 m long with an inside diameter of 150 mm (Darcy friction factor f = 0.015) 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), 3 bends (K = 0.3 each) and a valve (K = 5). 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 = 150 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 5
H = m
6.Hard
K = 10Δz = ?L = 400 m, D = 300 mm, f = 0.0222× bend (K = 0.3)

Two open reservoirs are joined by a pipe 400 m long with an inside diameter of 300 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 = 400 mD = 300 mmf = 0.022Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 10Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 403.3
  2. 2. Re = 263158
  3. 3. hf = 0.6529 m
  4. 4. hf = 21.94 m
  5. 5. H = 1.775 m
  6. 6. Δz = 6.086 m

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