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 = 2.25 m/sD = 25 mmρ = 891 kg/m³, μ = 0.29 Pa·s

SAE 30 motor oil (ρ = 891 kg/m³, μ = 0.29 Pa·s) flows at 2.25 m/s through a pipe with an inside diameter of 25 mm. Find the Reynolds number Re.

ρ = 891 kg/m³μ = 0.29 Pa·sV = 2.25 m/sD = 25 mm
Re =
2.Easy
Q = 3 L/sD = 40 mmν = 1.14 × 10⁻⁶ m²/s

Water at 15 °C (ν = 1.14 × 10⁻⁶ m²/s) flows through a pipe with an inside diameter of 40 mm at 3 L/s. Find the Reynolds number Re.

Q = 3 L/sD = 40 mmν = 1.14 × 10⁻⁶ m²/s
Re =
3.Medium
Q = 30 L/sD = 150 mmL = 150 mf = 0.028

Water flows at 30 L/s through a pipe 150 m long with an inside diameter of 150 mm. Use the Darcy friction factor f = 0.028 and g = 9.81 m/s². Find the friction head loss hf.

Q = 30 L/sL = 150 mD = 150 mmf = 0.028g = 9.81 m/s²
hf = m
4.Medium
V = 2.1 m/sD = 50 mmL = 500 mf = 0.022

Water (ρ = 1000 kg/m³) flows at 2.1 m/s through a horizontal pipe, 500 m long, with an inside diameter of 50 mm. Use the Darcy friction factor f = 0.022 and g = 9.81 m/s². Find the pressure drop Δp over the pipe in kPa.

V = 2.1 m/sL = 500 mD = 50 mmf = 0.022ρ = 1000 kg/m³
Δp = kPa
5.Hard
K = 10Δz = 19 mL = 100 m, D = 150 mm, f = 0.0222× 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 = 0.022. The water surface of the upper reservoir is 19 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 = 10) 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 = 19 mL = 100 mD = 150 mmf = 0.022Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 10Kexit = 1.0
Q = L/s
6.Hard
K = 5free outletH = ?L = 100 m, D = 300 mm, f = 0.024× bend (K = 0.3)

A pipe 100 m long with an inside diameter of 300 mm (Darcy friction factor f = 0.02) 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 = 5). Use g = 9.81 m/s². How far H must the reservoir surface be above the pipe outlet for a flow rate of 75 L/s?

Q = 75 L/sL = 100 mD = 300 mmf = 0.02Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 5
H = m

Answer key

  1. 1. Re = 172.8
  2. 2. Re = 83766
  3. 3. hf = 4.113 m
  4. 4. Δp = 485.1 kPa
  5. 5. Q = 65.95 L/s
  6. 6. H = 0.8244 m

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