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 = 150 mmρ = 850 kg/m³, μ = 0.005 Pa·s

Light fuel oil (ρ = 850 kg/m³, μ = 0.005 Pa·s) flows at 2.5 m/s through a pipe with an inside diameter of 150 mm. Find the Reynolds number Re.

ρ = 850 kg/m³μ = 0.005 Pa·sV = 2.5 m/sD = 150 mm
Re =
2.Easy
V = 1.25 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 1.25 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 = 1.25 m/sD = 25 mm
Re =
3.Medium
V = 2.3 m/sD = 250 mmL = 400 mf = 0.022

Water (ρ = 1000 kg/m³) flows at 2.3 m/s through a horizontal 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 pressure drop Δp over the pipe in kPa.

V = 2.3 m/sL = 400 mD = 250 mmf = 0.022ρ = 1000 kg/m³
Δp = kPa
4.Medium
Q = 25 L/sD = 100 mmL = 150 mf = 0.03

Water flows at 25 L/s through a pipe 150 m long with an inside diameter of 100 mm. Use the Darcy friction factor f = 0.03 and g = 9.81 m/s². Find the friction head loss hf.

Q = 25 L/sL = 150 mD = 100 mmf = 0.03g = 9.81 m/s²
hf = m
5.Hard
K = 10Δz = 38 mL = 150 m, D = 200 mm, f = 0.0253× bend (K = 0.3)

Two open reservoirs are joined by a pipe 150 m long with an inside diameter of 200 mm and a Darcy friction factor f = 0.025. The water surface of the upper reservoir is 38 m above that of the lower one. The minor losses are a square-edged entrance (K = 0.5), 3 bends (K = 0.3 each), a valve (K = 10) 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 = 38 mL = 150 mD = 200 mmf = 0.025Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 10Kexit = 1.0
Q = L/s
6.Hard
K = 2Δz = ?L = 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 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 = 300 mD = 200 mmf = 0.02Kentrance = 0.5Kbend = 0.3 (×4)Kvalve = 2Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 63750
  2. 2. Re = 96.01
  3. 3. Δp = 93.1 kPa
  4. 4. hf = 23.24 m
  5. 5. Q = 153.7 L/s
  6. 6. Δz = 11.47 m

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