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 = 3 m/sD = 100 mmν = 0.801 × 10⁻⁶ m²/s

Water at 30 °C (ν = 0.801 × 10⁻⁶ m²/s) flows at a mean velocity of 3 m/s through a pipe with an inside diameter of 100 mm. Find the Reynolds number Re.

V = 3 m/sD = 100 mmν = 0.801 × 10⁻⁶ m²/s
Re =
2.Easy
Q = 5 L/sD = 75 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 75 mm at 5 L/s. Find the Reynolds number Re.

Q = 5 L/sD = 75 mmν = 1.00 × 10⁻⁶ m²/s
Re =
3.Medium
V = 2.2 m/sD = 75 mmL = 500 mf = 0.022

Water flows at a mean velocity of 2.2 m/s through a pipe 500 m long with an inside diameter of 75 mm. Use the Darcy friction factor f = 0.022 and g = 9.81 m/s². Find the friction head loss hf.

V = 2.2 m/sL = 500 mD = 75 mmf = 0.022g = 9.81 m/s²
hf = m
4.Medium
V = 2.6 m/sD = 250 mmL = 800 mf = 0.02

Water (ρ = 1000 kg/m³) flows at 2.6 m/s through a horizontal pipe, 800 m long, with an inside diameter of 250 mm. Use the Darcy friction factor f = 0.02 and g = 9.81 m/s². Find the pressure drop Δp over the pipe in kPa.

V = 2.6 m/sL = 800 mD = 250 mmf = 0.02ρ = 1000 kg/m³
Δp = kPa
5.Hard
K = 2free outletH = ?L = 150 m, D = 150 mm, f = 0.0154× bend (K = 0.3)

A pipe 150 m long with an inside diameter of 150 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), 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 20 L/s?

Q = 20 L/sL = 150 mD = 150 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 2
H = m
6.Hard
K = 5Δz = ?L = 100 m, D = 150 mm, f = 0.024× 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 = 0.02. The minor losses are a square-edged entrance (K = 0.5), 4 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. What difference in water level Δz between the reservoirs gives a flow rate of 20 L/s?

Q = 20 L/sL = 100 mD = 150 mmf = 0.02Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 5Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 374532
  2. 2. Re = 84883
  3. 3. hf = 36.18 m
  4. 4. Δp = 216.3 kPa
  5. 5. H = 1.286 m
  6. 6. Δz = 1.373 m

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