Calculation of a Premixed Swirl Combustor Using the PDF Method

Abstract

The evolution probability density function (PDF) method provides a framework for the simulation of both diffusion and premixed turbulent flames. With this method, the chemical reaction rates are treated without approximation. In contrast, the conventional Reynolds-average methods need to model the mean reaction rates in turbulent flame calculations. In addition, conventional methods require special models for premixed flames that are developed under restrictive assumptions and rely on ad hoc expressions for the rate of reaction progress. The present work demonstrates the capability of the PDF method in realistic combustor design calculations. A lean premixed flame swirl combustor is simulated using the scalar PDF method, and the results are compared with experimental data. It is shown that the PDF method can correctly predict the turbulent flame speed and location of the flame. The ability of the PDF method to handle finite-rate complex chemistry of any number of reaction steps makes it an ideal candidate for emissions predictions in low emission combustor designs.