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 = 25 mmρ = 850 kg/m³, μ = 0.005 Pa·s

Light fuel oil (ρ = 850 kg/m³, μ = 0.005 Pa·s) flows at 1.75 m/s through a pipe with an inside diameter of 25 mm. Find the Reynolds number Re.

ρ = 850 kg/m³μ = 0.005 Pa·sV = 1.75 m/sD = 25 mm
Re =
2.Easy
Q = 4 L/sD = 50 mmν = 1.00 × 10⁻⁶ m²/s

Water at 20 °C (ν = 1.00 × 10⁻⁶ m²/s) flows through a pipe with an inside diameter of 50 mm at 4 L/s. Find the Reynolds number Re.

Q = 4 L/sD = 50 mmν = 1.00 × 10⁻⁶ m²/s
Re =
3.Medium
Q = 120 L/sD = 250 mmL = 400 mf = 0.025

Water flows at 120 L/s through a pipe 400 m long with an inside diameter of 250 mm. Use the Darcy friction factor f = 0.025 and g = 9.81 m/s². Find the friction head loss hf.

Q = 120 L/sL = 400 mD = 250 mmf = 0.025g = 9.81 m/s²
hf = m
4.Medium
V = 2 m/sD = 250 mmL = 100 mf = 0.025

Water (ρ = 1000 kg/m³) flows at 2 m/s through a horizontal pipe, 100 m long, with an inside diameter of 250 mm. Use the Darcy friction factor f = 0.025 and g = 9.81 m/s². Find the pressure drop Δp over the pipe in kPa.

V = 2 m/sL = 100 mD = 250 mmf = 0.025ρ = 1000 kg/m³
Δp = kPa
5.Hard
K = 0.2Δz = ?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 = 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 60 L/s?

Q = 60 L/sL = 100 mD = 150 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 0.2Kexit = 1.0
Δz = m
6.Hard
K = 5free outletH = ?L = 300 m, D = 250 mm, f = 0.0223× bend (K = 0.3)

A pipe 300 m long with an inside diameter of 250 mm (Darcy friction factor f = 0.022) 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), 3 bends (K = 0.3 each) and a valve (K = 5). Use g = 9.81 m/s². How far H must the reservoir surface be above the pipe outlet for a flow rate of 50 L/s?

Q = 50 L/sL = 300 mD = 250 mmf = 0.022Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 5
H = m

Answer key

  1. 1. Re = 7438
  2. 2. Re = 101859
  3. 3. hf = 12.18 m
  4. 4. Δp = 20 kPa
  5. 5. Δz = 7.58 m
  6. 6. H = 1.787 m

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