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 = 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 2.75 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 = 2.75 m/sD = 40 mm
Re =
2.Easy
V = 2.5 m/sD = 50 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 50 mm. Find the Reynolds number Re.

ρ = 891 kg/m³μ = 0.29 Pa·sV = 2.5 m/sD = 50 mm
Re =
3.Medium
Q = 10 L/sD = 150 mmL = 200 mf = 0.03

Water flows at 10 L/s through a 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 friction head loss hf.

Q = 10 L/sL = 200 mD = 150 mmf = 0.03g = 9.81 m/s²
hf = m
4.Medium
V = 1 m/sD = 75 mmL = 400 mf = 0.028

Water (ρ = 1000 kg/m³) flows at 1 m/s through a horizontal pipe, 400 m long, with an inside diameter of 75 mm. Use the Darcy friction factor f = 0.028 and g = 9.81 m/s². Find the pressure drop Δp over the pipe in kPa.

V = 1 m/sL = 400 mD = 75 mmf = 0.028ρ = 1000 kg/m³
Δp = kPa
5.Hard
K = 10Δz = ?L = 400 m, D = 200 mm, f = 0.0153× bend (K = 0.3)

Two open reservoirs are joined by a pipe 400 m long with an inside diameter of 200 mm and a Darcy friction factor f = 0.015. 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. What difference in water level Δz between the reservoirs gives a flow rate of 75 L/s?

Q = 75 L/sL = 400 mD = 200 mmf = 0.015Kentrance = 0.5Kbend = 0.3 (×3)Kvalve = 10Kexit = 1.0
Δz = m
6.Hard
K = 10Δz = ?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 = 10) 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 = 10Kexit = 1.0
Δz = m

Answer key

  1. 1. Re = 338
  2. 2. Re = 384.1
  3. 3. hf = 0.6529 m
  4. 4. Δp = 74.67 kPa
  5. 5. Δz = 12.32 m
  6. 6. Δz = 10.81 m

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