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 = 2.2 m/sD = 25 mmν = 0.801 × 10⁻⁶ m²/s

Water at 30 °C (ν = 0.801 × 10⁻⁶ m²/s) flows at a mean velocity of 2.2 m/s through a pipe with an inside diameter of 25 mm. Find the Reynolds number Re.

V = 2.2 m/sD = 25 mmν = 0.801 × 10⁻⁶ m²/s
Re =
2.Easy
V = 1 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 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 m/sD = 75 mm
Re =
3.Medium
V = 0.9 m/sD = 75 mmL = 100 mf = 0.018

Water flows at a mean velocity of 0.9 m/s through a pipe 100 m long with an inside diameter of 75 mm. Use the Darcy friction factor f = 0.018 and g = 9.81 m/s². Find the friction head loss hf.

V = 0.9 m/sL = 100 mD = 75 mmf = 0.018g = 9.81 m/s²
hf = m
4.Medium
V = 2.6 m/sD = 50 mmL = 400 mf = 0.028

Water (ρ = 1000 kg/m³) flows at 2.6 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 = 2.6 m/sL = 400 mD = 50 mmf = 0.028ρ = 1000 kg/m³
Δp = kPa
5.Hard
K = 5Δz = 15 mL = 100 m, D = 100 mm, f = 0.0252× bend (K = 0.3)

Two open reservoirs are joined by a pipe 100 m long with an inside diameter of 100 mm and a Darcy friction factor f = 0.025. The water surface of the upper reservoir is 15 m above that of the lower one. 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. Find the flow rate Q in L/s.

Δz = 15 mL = 100 mD = 100 mmf = 0.025Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 5Kexit = 1.0
Q = L/s
6.Hard
K = 2free outletH = ?L = 100 m, D = 200 mm, f = 0.0184× bend (K = 0.3)

A pipe 100 m long with an inside diameter of 200 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), 4 bends (K = 0.3 each) and a valve (K = 2). Use g = 9.81 m/s². How far H must the reservoir surface be above the pipe outlet for a flow rate of 40 L/s?

Q = 40 L/sL = 100 mD = 200 mmf = 0.018Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 2
H = m

Answer key

  1. 1. Re = 68664
  2. 2. Re = 230.4
  3. 3. hf = 0.9908 m
  4. 4. Δp = 757.1 kPa
  5. 5. Q = 23.78 L/s
  6. 6. H = 1.132 m

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