THE INFLUENCE OF THE TEMPERATURE-FLUCTUATIONS VARIANCE ON NO PREDICTIONS FOR A GAS FLAME

An experimental and theoretical activity has been carried but to inves tigate the influence of the statistical description of temperature flu ctuations on total NO emission predictions in a turbulent gas diffusio n flame. A small cylindrical combustor has been simulated, using a com mercial CFD code describing flow and combustion processes, integrated with a decoupled NO kinetics model that solves the transport equation of the average NO mass fraction. From the comparison of the computed r esults with in-flame measurements of temperature and species concentra tions it can be concluded that modelling of the temperature variance t ransport equation is required to obtain correct NO predictions, and th at results are sensitive to how the combustion contribution to the var iance source term is handled.