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 = 0.7 m/sD = 25 mmν = 1.00 × 10⁻⁶ m²/s

Water at 20 °C (ν = 1.00 × 10⁻⁶ m²/s) flows at a mean velocity of 0.7 m/s through a pipe with an inside diameter of 25 mm. Find the Reynolds number Re.

V = 0.7 m/sD = 25 mmν = 1.00 × 10⁻⁶ m²/s
Re =
2.Easy
V = 1 m/sD = 50 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 m/s through a pipe with an inside diameter of 50 mm. Find the Reynolds number Re.

ρ = 891 kg/m³μ = 0.29 Pa·sV = 1 m/sD = 50 mm
Re =
3.Medium
V = 1.6 m/sD = 100 mmL = 100 mf = 0.025

Water (ρ = 1000 kg/m³) flows at 1.6 m/s through a horizontal pipe, 100 m long, with an inside diameter of 100 mm. Use the Darcy friction factor f = 0.025 and g = 9.81 m/s². Find the pressure drop Δp over the pipe in kPa.

V = 1.6 m/sL = 100 mD = 100 mmf = 0.025ρ = 1000 kg/m³
Δp = kPa
4.Medium
V = 0.8 m/sD = 300 mmL = 200 mf = 0.018

Water flows at a mean velocity of 0.8 m/s through a pipe 200 m long with an inside diameter of 300 mm. Use the Darcy friction factor f = 0.018 and g = 9.81 m/s². Find the friction head loss hf.

V = 0.8 m/sL = 200 mD = 300 mmf = 0.018g = 9.81 m/s²
hf = m
5.Hard
K = 10Δz = ?L = 100 m, D = 100 mm, f = 0.0224× bend (K = 0.3)

Two open reservoirs are joined by a pipe 100 m long with an inside diameter of 100 mm and a Darcy friction factor f = 0.022. The minor losses are a square-edged entrance (K = 0.5), 4 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 20 L/s?

Q = 20 L/sL = 100 mD = 100 mmf = 0.022Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 10Kexit = 1.0
Δz = m
6.Hard
K = 5Δz = ?L = 100 m, D = 100 mm, f = 0.0224× bend (K = 0.3)

Two open reservoirs are joined by a pipe 100 m long with an inside diameter of 100 mm and a Darcy friction factor f = 0.022. The minor losses are a square-edged entrance (K = 0.5), 4 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. What difference in water level Δz between the reservoirs gives a flow rate of 20 L/s?

Q = 20 L/sL = 100 mD = 100 mmf = 0.022Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 5Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 17500
  2. 2. Re = 153.6
  3. 3. Δp = 32 kPa
  4. 4. hf = 0.3914 m
  5. 5. Δz = 11.47 m
  6. 6. Δz = 9.816 m

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