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 = 1.6 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 1.6 m/s through a pipe with an inside diameter of 150 mm. Find the Reynolds number Re.

V = 1.6 m/sD = 150 mmν = 0.801 × 10⁻⁶ m²/s
Re =
2.Easy
V = 0.5 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 0.5 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 = 0.5 m/sD = 50 mm
Re =
3.Medium
V = 1.8 m/sD = 250 mmL = 50 mf = 0.022

Water flows at a mean velocity of 1.8 m/s through a pipe 50 m long with an inside diameter of 250 mm. Use the Darcy friction factor f = 0.022 and g = 9.81 m/s². Find the friction head loss hf.

V = 1.8 m/sL = 50 mD = 250 mmf = 0.022g = 9.81 m/s²
hf = m
4.Medium
V = 2.8 m/sD = 75 mmL = 50 mf = 0.025

Water (ρ = 1000 kg/m³) flows at 2.8 m/s through a horizontal pipe, 50 m long, with an inside diameter of 75 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 = 2.8 m/sL = 50 mD = 75 mmf = 0.025ρ = 1000 kg/m³
Δp = kPa
5.Hard
K = 0.2Δz = 18 mL = 100 m, D = 100 mm, f = 0.023× 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 = 0.02. The water surface of the upper reservoir is 18 m above that of the lower one. 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. Find the flow rate Q in L/s.

Δz = 18 mL = 100 mD = 100 mmf = 0.02Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 0.2Kexit = 1.0
Q = L/s
6.Hard
K = 2free outletH = ?L = 100 m, D = 200 mm, f = 0.0153× bend (K = 0.3)

A pipe 100 m long with an inside diameter of 200 mm (Darcy friction factor f = 0.015) 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 = 2). Use g = 9.81 m/s². How far H must the reservoir surface be above the pipe outlet for a flow rate of 60 L/s?

Q = 60 L/sL = 100 mD = 200 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 2
H = m

Answer key

  1. 1. Re = 299625
  2. 2. Re = 76.81
  3. 3. hf = 0.7266 m
  4. 4. Δp = 65.33 kPa
  5. 5. Q = 31.05 L/s
  6. 6. H = 2.212 m

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