Turbulent Flame Speed Calculator

Turbulent Flame Speed Calculator

Turbulence wrinkles a flame front, and in the simplest and oldest model of this effect - proposed by Damkohler in 1940 - that wrinkling adds directly to the flame's effective propagation speed.

The formula: S_T = S_L + u'

Add the laminar burning velocity to the RMS turbulence intensity to get the turbulent flame speed. It is a simplification - modern correlations account for flame stretch and quenching at high turbulence - but it remains a useful first estimate and is still widely taught as the starting point for turbulent combustion.

Example: a laminar burning velocity of 0.4 m/s in a flow with 2.0 m/s of turbulence intensity gives a turbulent flame speed of 2.4 m/s - six times faster than the laminar case alone.

Frequently Asked Questions

Does this model work at very high turbulence?
No - at high turbulence intensities, real flames experience quenching effects this simple additive model does not capture, so it is most reliable at moderate turbulence levels.

Why does turbulence speed up a flame at all?
A wrinkled, folded flame front has more surface area than a flat one, and since burning rate scales with flame surface area, more wrinkling means faster overall fuel consumption even though the local burning velocity is unchanged.

See also the Laminar Burning Velocity Calculator for the baseline S_L value.