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 = 2.5 m/sD = 100 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 100 mm. Find the Reynolds number Re.

ρ = 891 kg/m³μ = 0.29 Pa·sV = 2.5 m/sD = 100 mm
Re =
2.Easy
V = 0.5 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 0.5 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 = 0.5 m/sD = 25 mm
Re =
3.Medium
Q = 80 L/sD = 250 mmL = 50 mf = 0.03

Water flows at 80 L/s through a pipe 50 m long with an inside diameter of 250 mm. Use the Darcy friction factor f = 0.03 and g = 9.81 m/s². Find the friction head loss hf.

Q = 80 L/sL = 50 mD = 250 mmf = 0.03g = 9.81 m/s²
hf = m
4.Medium
V = 3 m/sD = 200 mmL = 100 mf = 0.018

Water flows at a mean velocity of 3 m/s through a pipe 100 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.

V = 3 m/sL = 100 mD = 200 mmf = 0.018g = 9.81 m/s²
hf = m
5.Hard
K = 2free outletH = ?L = 100 m, D = 250 mm, f = 0.023× bend (K = 0.3)

A pipe 100 m long with an inside diameter of 250 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 120 L/s?

Q = 120 L/sL = 100 mD = 250 mmf = 0.02Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 2
H = m
6.Hard
K = 2Δz = ?L = 200 m, D = 200 mm, f = 0.024× bend (K = 0.3)

Two open reservoirs are joined by a pipe 200 m long with an inside diameter of 200 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 = 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 80 L/s?

Q = 80 L/sL = 200 mD = 200 mmf = 0.02Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 2Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 768.1
  2. 2. Re = 38.41
  3. 3. hf = 0.8123 m
  4. 4. hf = 4.128 m
  5. 5. H = 3.777 m
  6. 6. Δz = 8.164 m

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