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 = 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 1.5 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 = 1.5 m/sD = 50 mm
Re =
2.Easy
V = 1.8 m/sD = 150 mmν = 0.801 × 10⁻⁶ m²/s

Water at 30 °C (ν = 0.801 × 10⁻⁶ m²/s) flows at a mean velocity of 1.8 m/s through a pipe with an inside diameter of 150 mm. Find the Reynolds number Re.

V = 1.8 m/sD = 150 mmν = 0.801 × 10⁻⁶ m²/s
Re =
3.Medium
V = 2.4 m/sD = 75 mmL = 150 mf = 0.03

Water (ρ = 1000 kg/m³) flows at 2.4 m/s through a horizontal pipe, 150 m long, with an inside diameter of 75 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 = 2.4 m/sL = 150 mD = 75 mmf = 0.03ρ = 1000 kg/m³
Δp = kPa
4.Medium
V = 2.3 m/sD = 250 mmL = 100 mf = 0.018

Water (ρ = 1000 kg/m³) flows at 2.3 m/s through a horizontal pipe, 100 m long, with an inside diameter of 250 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 = 2.3 m/sL = 100 mD = 250 mmf = 0.018ρ = 1000 kg/m³
Δp = kPa
5.Hard
K = 0.2Δz = ?L = 100 m, D = 200 mm, f = 0.0223× bend (K = 0.3)

Two open reservoirs are joined by a pipe 100 m long with an inside diameter of 200 mm and a Darcy friction factor f = 0.022. The minor losses are a square-edged entrance (K = 0.5), 3 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. What difference in water level Δz between the reservoirs gives a flow rate of 75 L/s?

Q = 75 L/sL = 100 mD = 200 mmf = 0.022Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 0.2Kexit = 1.0
Δz = m
6.Hard
K = 10free outletH = ?L = 500 m, D = 300 mm, f = 0.0182× bend (K = 0.3)

A pipe 500 m long with an inside diameter of 300 mm (Darcy friction factor f = 0.018) runs from an open reservoir and discharges as a free jet into the air. The minor losses are a square-edged entrance (K = 0.5), 2 bends (K = 0.3 each) and a valve (K = 10). Use g = 9.81 m/s². How far H must the reservoir surface be above the pipe outlet for a flow rate of 80 L/s?

Q = 80 L/sL = 500 mD = 300 mmf = 0.018Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 10
H = m

Answer key

  1. 1. Re = 230.4
  2. 2. Re = 337079
  3. 3. Δp = 172.8 kPa
  4. 4. Δp = 19.04 kPa
  5. 5. Δz = 3.951 m
  6. 6. H = 2.749 m

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