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 = 25 L/sD = 150 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 150 mm at 25 L/s. Find the Reynolds number Re.

Q = 25 L/sD = 150 mmν = 0.801 × 10⁻⁶ m²/s
Re =
2.Easy
V = 0.75 m/sD = 40 mmρ = 880 kg/m³, μ = 0.04 Pa·s

Hydraulic oil (ρ = 880 kg/m³, μ = 0.04 Pa·s) flows at 0.75 m/s through a pipe with an inside diameter of 40 mm. Find the Reynolds number Re.

ρ = 880 kg/m³μ = 0.04 Pa·sV = 0.75 m/sD = 40 mm
Re =
3.Medium
V = 1.5 m/sD = 150 mmL = 400 mf = 0.03

Water flows at a mean velocity of 1.5 m/s through a pipe 400 m long with an inside diameter of 150 mm. Use the Darcy friction factor f = 0.03 and g = 9.81 m/s². Find the friction head loss hf.

V = 1.5 m/sL = 400 mD = 150 mmf = 0.03g = 9.81 m/s²
hf = m
4.Medium
V = 0.9 m/sD = 100 mmL = 1000 mf = 0.018

Water flows at a mean velocity of 0.9 m/s through a pipe 1000 m long with an inside diameter of 100 mm. Use the Darcy friction factor f = 0.018 and g = 9.81 m/s². Find the friction head loss hf.

V = 0.9 m/sL = 1000 mD = 100 mmf = 0.018g = 9.81 m/s²
hf = m
5.Hard
K = 0.2free outletH = ?L = 150 m, D = 200 mm, f = 0.0153× bend (K = 0.3)

A pipe 150 m long with an inside diameter of 200 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 = 0.2). Use g = 9.81 m/s². How far H must the reservoir surface be above the pipe outlet for a flow rate of 60 L/s?

Q = 60 L/sL = 150 mD = 200 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 0.2
H = m
6.Hard
K = 0.2Δz = ?L = 100 m, D = 150 mm, f = 0.0252× 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 = 0.025. 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 40 L/s?

Q = 40 L/sL = 100 mD = 150 mmf = 0.025Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 0.2Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 264927
  2. 2. Re = 660
  3. 3. hf = 9.174 m
  4. 4. hf = 7.431 m
  5. 5. H = 2.575 m
  6. 6. Δz = 4.953 m

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