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

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.

Budgets of Turbulent Kinetic Energy and Reynolds Normal Stresses in Coaxial Jets with and Without Swirl: A Numerical Study

“…In the present study, a configuration of unconfined coaxial jets with a strong swirl is investigated and compared with a case of non-swirl. Computational fluid dynamics (CFD) have been used extensively in the past [Dinesh et al, 2010;Javadi and Nilsson, 2015;Balaji et al, 2016] to acquire in-depth knowledge of the swirling flows and is also used in the present study. The numerical results are validated with the experimental measurements.…”