How to use
Enter actual inside diameter, length, flow, density, dynamic viscosity and roughness. Add total minor-loss coefficients for bends and valves.
Example calculation
D = 100 mm, L = 10 m, Q ≈ 471.239 L/min, ρ = 1000, μ = 1 mPa·s, ε = 0.01 mm, ΣK = 2: v = 1 m/s, Re = 100000, Δp ≈ 1925.69 Pa.
Calculation method
v = Q/(πD²/4); Re = ρvD/μ Re < 2300: f = 64/Re Re ≥ 4000: 1/√f = −2 log₁₀[ε/(3.7D) + 2.51/(Re√f)] Δp = (fL/D + ΣK)ρv²/2; H_loss = Δp/(ρg) Q: m³/s; D, L, ε: m; μ: Pa·s; Δp: Pa
Calculation limits
Full circular pipe, single-phase Newtonian liquid. Re < 2300 is laminar; Re ≥ 4000 uses Colebrook; transition is uncertain interpolation. ε/D ≤ 0.05. Excludes elevation, pumps, compressibility and cavitation.