ANALYSIS OF SCALAR PDF MODELS FOR TURBULENT NON-PREMKED COMBUSTION

Thermochemical scalar pdfs measured in nonpremixed hydrogen and methane turbulent jet flames are compared a priori with a sophisticated conventional assumed-shape pdf model, as well as a recently constructed pdf model. The constructed pdf, by incorporating the underlying physics of advection by all unsteady eddies, molecular diffusion and chemical reaction, displays consistent and substantial a priori improvement over the conventional assumed-shape pdf. In addition, the constructed pdf model is parameterized by considerably fewer lower moments, and in particular, first moments, promising affordable and accurate implementation in a moment equation solver. (Author