Reynolds Number Calculator
Reynolds Number Calculator: Determine Combustion Gas Flow Regime
Reynolds number is the single most important dimensionless number for characterizing fluid flow, telling you whether gas moves smoothly in orderly layers (laminar) or chaotically with intense mixing (turbulent). This distinction drives pressure drop, heat transfer, and mixing behavior throughout combustion systems.
The Formula
Re = (ρ × V × D) / μ
Worked Example
Gas with density 1.2 kg/m3 flows at 15 m/s through a 0.3 m diameter duct, with dynamic viscosity 1.8×10-5 Pa·s.
Re = (1.2 × 15 × 0.3) / 1.8×10-5 = 300,000 (turbulent flow)
How to Use This Calculator
- Enter the gas density in kg/m3.
- Enter the flow velocity in m/s.
- Enter the pipe or duct diameter in meters.
- Enter the gas's dynamic viscosity in Pa·s.
- Click Calculate to get the Reynolds number and flow regime.
Related Calculations
Use the result to select an appropriate friction factor for the Pressure Drop Calculator.