Numerical Investigation of Swirling Hydrogen Flames: Effect of Swirl and Fuel Jet in Coherent Structures

V. Suresh Balaji; Ashoke De; Santanu De

Authors

V. Suresh Balaji Department of Aerospace Engineering
Ashoke De Department of Aerospace Engineering
Santanu De Department of Mechanical Engineering Indian Institute of Technology, Kanpur-208 016, India

Keywords:

Swirling hydrogen flames, Large Eddy Simulation, Precessing Vortex Core

Abstract

The present work reports on the numerical investigation of turbulent swirling flames using Large Eddy Simulation (LES) methodology in conjunction with presumed shape PDF (Probability Density Function) based combustion models. The LES with dynamic-smagorinsky eddy viscosity model is used to study the different complex unsteady structures involved in the flow field. Sydney swirl burner, which is
considered as a reliable benchmark for numerical studies in swirling flames, is chosen as a test case. Two isothermal and three reacting test cases are considered for the present study. In the isothermal calculations, a precession vortex core is accurately captured. The precession vortex core structures, responsible for the instability in hydrogen-methane reacting cases, are analyzed using different visualization techniques. Phase averaging technique is also used to analyze the different repeated coherent structures responsible for the instability in the flow field.