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 = 1.25 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 1.25 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 = 1.25 m/sD = 40 mm
Re =
2.Easy
V = 1.75 m/sD = 40 mmρ = 891 kg/m³, μ = 0.29 Pa·s

SAE 30 motor oil (ρ = 891 kg/m³, μ = 0.29 Pa·s) flows at 1.75 m/s through a pipe with an inside diameter of 40 mm. Find the Reynolds number Re.

ρ = 891 kg/m³μ = 0.29 Pa·sV = 1.75 m/sD = 40 mm
Re =
3.Medium
V = 2.1 m/sD = 250 mmL = 500 mf = 0.022

Water flows at a mean velocity of 2.1 m/s through a pipe 500 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 = 2.1 m/sL = 500 mD = 250 mmf = 0.022g = 9.81 m/s²
hf = m
4.Medium
V = 2.8 m/sD = 250 mmL = 400 mf = 0.022

Water flows at a mean velocity of 2.8 m/s through a pipe 400 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 = 2.8 m/sL = 400 mD = 250 mmf = 0.022g = 9.81 m/s²
hf = m
5.Hard
K = 2free outletH = ?L = 200 m, D = 300 mm, f = 0.0153× bend (K = 0.3)

A pipe 200 m long with an inside diameter of 300 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 150 L/s?

Q = 150 L/sL = 200 mD = 300 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 2
H = m
6.Hard
K = 2Δz = ?L = 300 m, D = 250 mm, f = 0.0182× bend (K = 0.3)

Two open reservoirs are joined by a pipe 300 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.018. The minor losses are a square-edged entrance (K = 0.5), 2 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. What difference in water level Δz between the reservoirs gives a flow rate of 150 L/s?

Q = 150 L/sL = 300 mD = 250 mmf = 0.018Kentrance = 0.5Kbend = 0.3 (×2)Kvalve = 2Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 1100
  2. 2. Re = 215.1
  3. 3. hf = 9.89 m
  4. 4. hf = 14.07 m
  5. 5. H = 3.305 m
  6. 6. Δz = 12.23 m

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