(47i) Homogenous-Gaseous and Particle-Gas-Air Combustion in Turbulent Environment: Analytical Formulation and Experimental Validation

Analytical studies of premixed turbulent flame velocity, namely, the renormalization approach of Bychkov et al [Combust. Sci. Tech. 179 (2007) 137] and the spectral formulation of Chaudhuri et al [Phys. Rev. E 84 (2011) 026322] are reconciled, and validated by Hybrid-Flame Analyzer experiments on turbulent methane-air burning [Combust. Flame 160 (2013) 635]. Both the homogenous gaseous premixtures as well as the particle-gas-air systems containing coal-duct impurities are investigated. The turbulent flame velocity is tabulated as a function of various flame parameters (such as the laminar flame speed, thermal expansion coefficient, etc.) and flow parameters (such as the turbulent intensity, integral and Kolmogorov length scales, etc.) as well as that of the sizes and concentrations of the impurity particles. Specifically, it is shown that the particles typically intensify turbulent combustion. The formulation accounts for the flame-flow feedback due to thermal expansion. Besides, turbulence coupling to the intrinsic combustion instabilities is analyzed by means of the concept of the turbulence-induced Darrieus-Landau cutoff wavelength. It is eventually demonstrated how multi-phase impurities and turbulence-instability interaction modify the conventional turbulent combustion regimes diagram.