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 = 2.75 m/sD = 75 mmρ = 850 kg/m³, μ = 0.005 Pa·s

Light fuel oil (ρ = 850 kg/m³, μ = 0.005 Pa·s) flows at 2.75 m/s through a pipe with an inside diameter of 75 mm. Find the Reynolds number Re.

ρ = 850 kg/m³μ = 0.005 Pa·sV = 2.75 m/sD = 75 mm
Re =
2.Easy
V = 1.4 m/sD = 40 mmν = 1.31 × 10⁻⁶ m²/s

Water at 10 °C (ν = 1.31 × 10⁻⁶ m²/s) flows at a mean velocity of 1.4 m/s through a pipe with an inside diameter of 40 mm. Find the Reynolds number Re.

V = 1.4 m/sD = 40 mmν = 1.31 × 10⁻⁶ m²/s
Re =
3.Medium
V = 1.2 m/sD = 50 mmL = 50 mf = 0.03

Water (ρ = 1000 kg/m³) flows at 1.2 m/s through a horizontal pipe, 50 m long, with an inside diameter of 50 mm. Use the Darcy friction factor f = 0.03 and g = 9.81 m/s². Find the pressure drop Δp over the pipe in kPa.

V = 1.2 m/sL = 50 mD = 50 mmf = 0.03ρ = 1000 kg/m³
Δp = kPa
4.Medium
V = 1.2 m/sD = 300 mmL = 800 mf = 0.018

Water (ρ = 1000 kg/m³) flows at 1.2 m/s through a horizontal pipe, 800 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 pressure drop Δp over the pipe in kPa.

V = 1.2 m/sL = 800 mD = 300 mmf = 0.018ρ = 1000 kg/m³
Δp = kPa
5.Hard
K = 5Δz = 16 mL = 150 m, D = 100 mm, f = 0.0153× 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 water surface of the upper reservoir is 16 m above that of the lower one. The minor losses are a square-edged entrance (K = 0.5), 3 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. Find the flow rate Q in L/s.

Δz = 16 mL = 150 mD = 100 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 5Kexit = 1.0
Q = L/s
6.Hard
K = 5Δz = ?L = 150 m, D = 250 mm, f = 0.0154× bend (K = 0.3)

Two open reservoirs are joined by a pipe 150 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.015. 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 60 L/s?

Q = 60 L/sL = 150 mD = 250 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 5Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 35063
  2. 2. Re = 42748
  3. 3. Δp = 21.6 kPa
  4. 4. Δp = 34.56 kPa
  5. 5. Q = 25.45 L/s
  6. 6. Δz = 1.272 m

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