Premixed Turbulent Combustion Controlled by Complex Chemical Kinetics

Abstract

The combustion of a turbulent homogeneous mixture of propane and air within a duct having a stationary one-dimensional mean flow is modelled. Under the conditions chosen for the study, chemical kinetics factors are important and a relatively detailed chemical model is needed. A semi-global model for the combustion of hydrocarbon is used and simplifying assumptions are made which reduce the system of independent variables to that of temperature and CO₂ mass fraction. A two-dimensional probability density function is introduced to close the mean chemical production terms. The required equations for Favre averaged temperature, CO₂ mass fraction, turbulence kinetic energy and the mean square fluctuation of the temperature are solved numerically. Predictions are made of the profiles of mean quantities through the combustion zone under different initial temperature, turbulence intensities and dissipation length scales.