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 = 0.75 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 =
2.Easy
V = 2.6 m/sD = 150 mmν = 1.00 × 10⁻⁶ m²/s

Water at 20 °C (ν = 1.00 × 10⁻⁶ m²/s) flows at a mean velocity of 2.6 m/s through a pipe with an inside diameter of 150 mm. Find the Reynolds number Re.

V = 2.6 m/sD = 150 mmν = 1.00 × 10⁻⁶ m²/s
Re =
3.Medium
V = 2.8 m/sD = 50 mmL = 400 mf = 0.028

Water (ρ = 1000 kg/m³) flows at 2.8 m/s through a horizontal pipe, 400 m long, with an inside diameter of 50 mm. Use the Darcy friction factor f = 0.028 and g = 9.81 m/s². Find the pressure drop Δp over the pipe in kPa.

V = 2.8 m/sL = 400 mD = 50 mmf = 0.028ρ = 1000 kg/m³
Δp = kPa
4.Medium
V = 0.8 m/sD = 150 mmL = 150 mf = 0.018

Water (ρ = 1000 kg/m³) flows at 0.8 m/s through a horizontal pipe, 150 m long, with an inside diameter of 150 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 = 0.8 m/sL = 150 mD = 150 mmf = 0.018ρ = 1000 kg/m³
Δp = kPa
5.Hard
K = 0.2Δz = 14 mL = 100 m, D = 300 mm, f = 0.024× 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 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 = 0.2) 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 = 300 mmf = 0.02Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 0.2Kexit = 1.0
Q = L/s
6.Hard
K = 5Δz = ?L = 100 m, D = 250 mm, f = 0.0252× bend (K = 0.3)

Two open reservoirs are joined by a pipe 100 m long with an inside diameter of 250 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 = 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 120 L/s?

Q = 120 L/sL = 100 mD = 250 mmf = 0.025Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 5Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 660
  2. 2. Re = 390000
  3. 3. Δp = 878.1 kPa
  4. 4. Δp = 5.76 kPa
  5. 5. Q = 378.8 L/s
  6. 6. Δz = 5.209 m

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