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 = 40 mmρ = 880 kg/m³, μ = 0.04 Pa·s

Hydraulic oil (ρ = 880 kg/m³, μ = 0.04 Pa·s) flows at 1.75 m/s through a pipe with an inside diameter of 40 mm. Find the Reynolds number Re.

ρ = 880 kg/m³μ = 0.04 Pa·sV = 1.75 m/sD = 40 mm
Re =
2.Easy
V = 2.5 m/sD = 150 mmρ = 891 kg/m³, μ = 0.29 Pa·s

SAE 30 motor oil (ρ = 891 kg/m³, μ = 0.29 Pa·s) flows at 2.5 m/s through a pipe with an inside diameter of 150 mm. Find the Reynolds number Re.

ρ = 891 kg/m³μ = 0.29 Pa·sV = 2.5 m/sD = 150 mm
Re =
3.Medium
Q = 100 L/sD = 300 mmL = 150 mf = 0.018

Water flows at 100 L/s through a pipe 150 m long with an inside diameter of 300 mm. Use the Darcy friction factor f = 0.018 and g = 9.81 m/s². Find the friction head loss hf.

Q = 100 L/sL = 150 mD = 300 mmf = 0.018g = 9.81 m/s²
hf = m
4.Medium
V = 1.6 m/sD = 75 mmL = 800 mf = 0.015

Water (ρ = 1000 kg/m³) flows at 1.6 m/s through a horizontal pipe, 800 m long, with an inside diameter of 75 mm. Use the Darcy friction factor f = 0.015 and g = 9.81 m/s². Find the pressure drop Δp over the pipe in kPa.

V = 1.6 m/sL = 800 mD = 75 mmf = 0.015ρ = 1000 kg/m³
Δp = kPa
5.Hard
K = 2free outletH = ?L = 100 m, D = 300 mm, f = 0.023× 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), 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 75 L/s?

Q = 75 L/sL = 100 mD = 300 mmf = 0.02Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 2
H = m
6.Hard
K = 2Δz = 13 mL = 300 m, D = 200 mm, f = 0.024× bend (K = 0.3)

Two open reservoirs are joined by a pipe 300 m long with an inside diameter of 200 mm and a Darcy friction factor f = 0.02. The water surface of the upper reservoir is 13 m above that of the lower one. The minor losses are a square-edged entrance (K = 0.5), 4 bends (K = 0.3 each), a valve (K = 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 = 13 mL = 300 mD = 200 mmf = 0.02Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 2Kexit = 1.0
Q = L/s

Answer key

  1. 1. Re = 1540
  2. 2. Re = 1152
  3. 3. hf = 0.9181 m
  4. 4. Δp = 204.8 kPa
  5. 5. H = 0.635 m
  6. 6. Q = 85.17 L/s

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