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 = 80 L/sD = 200 mmν = 1.31 × 10⁻⁶ m²/s

Water at 10 °C (ν = 1.31 × 10⁻⁶ m²/s) flows through a pipe with an inside diameter of 200 mm at 80 L/s. Find the Reynolds number Re.

Q = 80 L/sD = 200 mmν = 1.31 × 10⁻⁶ m²/s
Re =
2.Easy
V = 0.5 m/sD = 40 mmρ = 850 kg/m³, μ = 0.005 Pa·s

Light fuel oil (ρ = 850 kg/m³, μ = 0.005 Pa·s) flows at 0.5 m/s through a pipe with an inside diameter of 40 mm. Find the Reynolds number Re.

ρ = 850 kg/m³μ = 0.005 Pa·sV = 0.5 m/sD = 40 mm
Re =
3.Medium
Q = 100 L/sD = 200 mmL = 500 mf = 0.025

Water flows at 100 L/s through a pipe 500 m long with an inside diameter of 200 mm. Use the Darcy friction factor f = 0.025 and g = 9.81 m/s². Find the friction head loss hf.

Q = 100 L/sL = 500 mD = 200 mmf = 0.025g = 9.81 m/s²
hf = m
4.Medium
V = 1.4 m/sD = 50 mmL = 500 mf = 0.018

Water flows at a mean velocity of 1.4 m/s through a pipe 500 m long with an inside diameter of 50 mm. Use the Darcy friction factor f = 0.018 and g = 9.81 m/s². Find the friction head loss hf.

V = 1.4 m/sL = 500 mD = 50 mmf = 0.018g = 9.81 m/s²
hf = m
5.Hard
K = 2free outletH = ?L = 300 m, D = 150 mm, f = 0.0154× bend (K = 0.3)

A pipe 300 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), 4 bends (K = 0.3 each) and a valve (K = 2). Use g = 9.81 m/s². How far H must the reservoir surface be above the pipe outlet for a flow rate of 30 L/s?

Q = 30 L/sL = 300 mD = 150 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 2
H = m
6.Hard
K = 0.2Δz = ?L = 100 m, D = 150 mm, f = 0.0152× bend (K = 0.3)

Two open reservoirs are joined by a pipe 100 m long with an inside diameter of 150 mm and a Darcy friction factor f = 0.015. The minor losses are a square-edged entrance (K = 0.5), 2 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. What difference in water level Δz between the reservoirs gives a flow rate of 20 L/s?

Q = 20 L/sL = 100 mD = 150 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 0.2Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 388775
  2. 2. Re = 3400
  3. 3. hf = 32.28 m
  4. 4. hf = 17.98 m
  5. 5. H = 5.097 m
  6. 6. Δz = 0.803 m

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