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 = 2.75 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 2.75 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 = 2.75 m/sD = 25 mm
Re =
2.Easy
V = 1.25 m/sD = 40 mmρ = 850 kg/m³, μ = 0.005 Pa·s

Light fuel oil (ρ = 850 kg/m³, μ = 0.005 Pa·s) flows at 1.25 m/s through a pipe with an inside diameter of 40 mm. Find the Reynolds number Re.

ρ = 850 kg/m³μ = 0.005 Pa·sV = 1.25 m/sD = 40 mm
Re =
3.Medium
V = 1 m/sD = 150 mmL = 200 mf = 0.03

Water (ρ = 1000 kg/m³) flows at 1 m/s through a horizontal pipe, 200 m long, with an inside diameter of 150 mm. Use the Darcy friction factor f = 0.03 and g = 9.81 m/s². Find the pressure drop Δp over the pipe in kPa.

V = 1 m/sL = 200 mD = 150 mmf = 0.03ρ = 1000 kg/m³
Δp = kPa
4.Medium
Q = 30 L/sD = 200 mmL = 1000 mf = 0.018

Water flows at 30 L/s through a pipe 1000 m long with an inside diameter of 200 mm. Use the Darcy friction factor f = 0.018 and g = 9.81 m/s². Find the friction head loss hf.

Q = 30 L/sL = 1000 mD = 200 mmf = 0.018g = 9.81 m/s²
hf = m
5.Hard
K = 10free outletH = ?L = 100 m, D = 250 mm, f = 0.0183× bend (K = 0.3)

A pipe 100 m long with an inside diameter of 250 mm (Darcy friction factor f = 0.018) 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 = 10). 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 = 250 mmf = 0.018Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 10
H = m
6.Hard
K = 0.2Δz = 19 mL = 100 m, D = 100 mm, f = 0.0154× 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 = 0.015. 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), 4 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 = 19 mL = 100 mD = 100 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 0.2Kexit = 1.0
Q = L/s

Answer key

  1. 1. Re = 211.2
  2. 2. Re = 8500
  3. 3. Δp = 20 kPa
  4. 4. hf = 4.183 m
  5. 5. H = 1.493 m
  6. 6. Q = 35.84 L/s

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