Turbulent Premixed Flames

  • List three practical examples of turbulent premixed flames in engineering.
  • What is the key conceptual/physical reason for the increase in turbulent flame speed compared to laminar flame speed.
  • The laminar flame speed is a thermochemical property of the fuel/air mixture at the given composition, temperature, and pressure. What about turbulent flame speeds?
  • What are the four turbulent premixed flame regimes?
    • On a number line, indicate the integral and Kolmogorov length scales, and indicate the flame thickness location corresponding to the four regimes.
  • Define the Damkohler number.
    • Does it use large or small scales for the flow?
    • If you have higher reaction rates, is Da higher or lower?
  • Define the Reynolds number in terms of the turbulent velocity fluctuations.
    • Define it using the laminar flame speed and thickness.
      • What assumption is made on $\nu$?
  • Define the Karlovitz number.
    • How is it related to the Damkohler number?