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 = 1.5 m/sD = 150 mmρ = 891 kg/m³, μ = 0.29 Pa·s

SAE 30 motor oil (ρ = 891 kg/m³, μ = 0.29 Pa·s) flows at 1.5 m/s through a pipe with an inside diameter of 150 mm. Find the Reynolds number Re.

ρ = 891 kg/m³μ = 0.29 Pa·sV = 1.5 m/sD = 150 mm
Re =
2.Easy
V = 1 m/sD = 150 mmν = 1.31 × 10⁻⁶ m²/s

Water at 10 °C (ν = 1.31 × 10⁻⁶ m²/s) flows at a mean velocity of 1 m/s through a pipe with an inside diameter of 150 mm. Find the Reynolds number Re.

V = 1 m/sD = 150 mmν = 1.31 × 10⁻⁶ m²/s
Re =
3.Medium
V = 2.4 m/sD = 150 mmL = 400 mf = 0.02

Water (ρ = 1000 kg/m³) flows at 2.4 m/s through a horizontal pipe, 400 m long, with an inside diameter of 150 mm. Use the Darcy friction factor f = 0.02 and g = 9.81 m/s². Find the pressure drop Δp over the pipe in kPa.

V = 2.4 m/sL = 400 mD = 150 mmf = 0.02ρ = 1000 kg/m³
Δp = kPa
4.Medium
V = 2.7 m/sD = 250 mmL = 800 mf = 0.015

Water (ρ = 1000 kg/m³) flows at 2.7 m/s through a horizontal pipe, 800 m long, with an inside diameter of 250 mm. Use the Darcy friction factor f = 0.015 and g = 9.81 m/s². Find the pressure drop Δp over the pipe in kPa.

V = 2.7 m/sL = 800 mD = 250 mmf = 0.015ρ = 1000 kg/m³
Δp = kPa
5.Hard
K = 10Δz = ?L = 150 m, D = 100 mm, f = 0.0152× bend (K = 0.3)

Two open reservoirs are joined by a pipe 150 m long with an inside diameter of 100 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 = 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 8 L/s?

Q = 8 L/sL = 150 mD = 100 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 10Kexit = 1.0
Δz = m
6.Hard
K = 2Δz = 14 mL = 100 m, D = 150 mm, f = 0.0154× 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 water surface of the upper reservoir is 14 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 = 14 mL = 100 mD = 150 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 2Kexit = 1.0
Q = L/s

Answer key

  1. 1. Re = 691.3
  2. 2. Re = 114504
  3. 3. Δp = 153.6 kPa
  4. 4. Δp = 175 kPa
  5. 5. Δz = 1.83 m
  6. 6. Q = 76.39 L/s

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