Karlovitz numbers and premixed turbulent combustion regimes for complex-chemistry flames
Review article, 2022

The structure of premixed turbulent flames and governing physical mechanisms of the influence of turbulence on premixed burning are often discussed by invoking combustion regime diagrams. In the majority of such diagrams, boundaries of three combustion regimes associated with (i) flame preheat zones broadened locally by turbulent eddies, (ii) reaction zones broadened locally by turbulent eddies, and (iii) local extinction are based on a Karlovitz number (Formula presented.), with differently defined (Formula presented.) being used to demarcate different combustion regimes. The present paper aims to overview different definitions of (Formula presented.), comparing them, and suggesting the most appropriate choice of (Formula presented.) for each combustion regime boundary. Moreover, since certain Karlovitz numbers involve a laminar flame thickness, the influence of complex combustion chemistry on the thickness and, hence, on various (Formula presented.) and relations between them is explored based on results of complex-chemistry simulations of unperturbed (stationary, planar, and one-dimensional) laminar premixed flames, obtained for various fuels, equivalence ratios, pressures, and unburned gas temperatures.

combustion regime diagram

complex chemistry

turbulent flame

Gas temperature

Karlovitz number

Combustion

Author

Andrei Lipatnikov

Chalmers, Mechanics and Maritime Sciences (M2), Combustion and Propulsion Systems

Vladimir Sabelnikov

Central Aerohydrodynamic Institute (TsAGI)

ONERA Centre de Palaiseau

Energies

1996-1073 (ISSN) 19961073 (eISSN)

Vol. 15 1-18 5840

Driving Forces

Sustainable development

Areas of Advance

Transport

Energy

Subject Categories

Energy Engineering

Fluid Mechanics and Acoustics

Roots

Basic sciences

DOI

10.3390/en15165840

More information

Latest update

10/26/2023