GIFSQ Tools · Module 17 — Food Processing, Thermal Engineering & Utilities · Tool 338 of 500
Work out the Reynolds number of a flow and whether it is laminar, transitional or turbulent, with the matching friction factor.
Try sample values — fills the form with the worked example below.
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Reynolds number
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Regime code (0/1/2)
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Friction factor (f)
Equation: Re = ρ × v × D / μ; laminar below 2300, transitional 2300–4000, turbulent above 4000; f = 64 / Re (laminar) or 0.316 × Re^( −0.25) (turbulent, Blasius, smooth pipe).
Method: Reynolds number classification with the Blasius friction factor, standard fluid mechanics practice (Cengel and Cimbala).
Assumptions: Newtonian fluid; circular pipe; fully developed flow; smooth pipe wall for the turbulent friction factor.
Limitations: the 2300/4000 limits are for pipe flow; transitional flow is unsteady and its friction factor is uncertain; non-Newtonian foods need a different Reynolds number.
Rounding: Reynolds number and regime code to 0 decimal places, friction factor to 4; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: Reynolds number classification with the Blasius friction factor, standard fluid mechanics practice (Cengel and Cimbala).
Assumptions: Newtonian fluid; circular pipe; fully developed flow; smooth pipe wall for the turbulent friction factor.
Limitations: the 2300/4000 limits are for pipe flow; transitional flow is unsteady and its friction factor is uncertain; non-Newtonian foods need a different Reynolds number.
Rounding: Reynolds number and regime code to 0 decimal places, friction factor to 4; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: Water at 1.4147 m/s in a 50 mm pipe (density 1000 kg/m³, viscosity 1 mPa·s): Re = 70735, regime code 2 (turbulent), f = 0.0194.
Enter values above to see results.
Regime codes: 0 = laminar (smooth, layered flow), 1 = transitional (unsteady), 2 = turbulent (mixed flow, better heat transfer). Tool 338 of 500 — GIFSQ
