Theory and Model of Turbulent Flames Based on Kolmogorov-type Hypotheses

Abstract

The monograph presents, for the first time comprehensively, the results of the original theory of turbulent premixed flames based on the Kolmogorov hypothesis approach and the model of turbulent premixed and partially premixed combustion, the foundation of which is this theory. This one-dimensional theory, associated with the constant density approximation, describes the internal structure and global properties of flames propagating through a turbulent medium that is described by Kolmogorov's theory. The combustion regimes of laminar flamelet, thickened (microturbulent) flamelet, and distributed preheat zone are considered, as well as different propagation stages corresponding to different statistical states of the instantaneous flame. Generalization of the kinematic equations describing the flame motions to the case of three-dimensional turbulent flows of variable density has led to the balance equations of the TFC combustion model (implemented in the CFD codes Fluent and CFX), which are used in combination with two-parameter Kolmogorov-type turbulence models. The results of validation of the RANS-, LES-, and joint RANS/LES versions of the TFC combustion model against standard experimental data and their practical applications are discussed. It is concluded that the hypothesis-driven approach provides a new framework for understanding turbulent flames, offering potential improvements in combustion efficiency and safety for industrial applications.