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 = 1.75 m/sD = 75 mmρ = 891 kg/m³, μ = 0.29 Pa·s

SAE 30 motor oil (ρ = 891 kg/m³, μ = 0.29 Pa·s) flows at 1.75 m/s through a pipe with an inside diameter of 75 mm. Find the Reynolds number Re.

ρ = 891 kg/m³μ = 0.29 Pa·sV = 1.75 m/sD = 75 mm
Re =
2.Easy
Q = 30 L/sD = 150 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 150 mm at 30 L/s. Find the Reynolds number Re.

Q = 30 L/sD = 150 mmν = 1.31 × 10⁻⁶ m²/s
Re =
3.Medium
Q = 10 L/sD = 100 mmL = 1000 mf = 0.022

Water flows at 10 L/s through a pipe 1000 m long with an inside diameter of 100 mm. Use the Darcy friction factor f = 0.022 and g = 9.81 m/s². Find the friction head loss hf.

Q = 10 L/sL = 1000 mD = 100 mmf = 0.022g = 9.81 m/s²
hf = m
4.Medium
V = 1.2 m/sD = 150 mmL = 150 mf = 0.015

Water (ρ = 1000 kg/m³) flows at 1.2 m/s through a horizontal pipe, 150 m long, with an inside diameter of 150 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 = 1.2 m/sL = 150 mD = 150 mmf = 0.015ρ = 1000 kg/m³
Δp = kPa
5.Hard
K = 5Δz = 5 mL = 100 m, D = 300 mm, f = 0.023× bend (K = 0.3)

Two open reservoirs are joined by a pipe 100 m long with an inside diameter of 300 mm and a Darcy friction factor f = 0.02. The water surface of the upper reservoir is 5 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 = 5 mL = 100 mD = 300 mmf = 0.02Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 5Kexit = 1.0
Q = L/s
6.Hard
K = 2Δz = ?L = 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 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. 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 = 0.015Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 2Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 403.3
  2. 2. Re = 194388
  3. 3. hf = 18.18 m
  4. 4. Δp = 10.8 kPa
  5. 5. Q = 186.7 L/s
  6. 6. Δz = 3.839 m

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