Flame Stability Calculator
Flame Stability Calculator: Assess Flashback and Blow-Off Risk
A stable burner flame requires the flow velocity of the fuel-air mixture to be balanced against the flame's own propagation speed. If flow velocity drops below the flame speed, the flame can travel upstream into the burner (flashback). If it rises too far above, the flame can detach and extinguish (blow-off). This calculator computes the stability ratio between the two.
The Formula
Stability Ratio = Flow Velocity / Flame Speed
Worked Example
A burner has a flow velocity of 25 m/s and a flame speed of 0.4 m/s.
Stability Ratio = 25 / 0.4 = 62.5, indicating a significant blow-off risk for a typical premixed burner.
How to Use This Calculator
- Enter the flow velocity of the fuel-air mixture at the burner port in m/s.
- Enter the flame speed for your fuel-air mixture in m/s (see the Flame Speed Calculator).
- Click Calculate to see the stability ratio and its interpretation.
Related Calculations
Use with the Flame Speed Calculator and Burner Turndown Ratio Calculator for a full burner operability check.