Simulating Bluff Body Flameholders: On the Use of Proper Orthogonal Decomposition for Combustion Dynamics Validation

Abstract

Contemporary tools for experimentation and computational modeling of unsteady and reacting flow open new opportunities for engineering insight into dynamic phenomena. In this article, we describe a novel use of proper orthogonal decomposition (POD) for validation of the unsteady heat release of a turbulent premixed flame stabilized by a veegutter bluffbody. Largeeddy simulations were conducted for the same geometry and flow conditions as examined in an experimental rig with chemiluminescence measurements obtained with a highspeed camera. In addition to comparing the experiment to the simulation using traditional timeaveraging and pointwise statistical techniques, the dynamic modes of each are isolated using proper orthogonal decomposition (POD) and then compared modebymode against each other. The results show good overall agreement between the shapes and magnitudes of the first modes of the measured and simulated data. A numerical study of into the effects of various simulation parameters on these heat release modes showed significant effects on the flame's effective angle but also on the size, shape, and symmetry patterns of the flame's dynamic modes.