Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
NUMERICAL STUDY OF DISTORTED TULIP FLAME PROPAGATION IN CLOSED CHANNELS
Submission Author:
Fernando Illacanchi Guerra , Lima , Peru
Co-Authors:
Fernando Illacanchi Guerra, René Sebastian Valencia Ramírez, Cesar Celis, Andrés Armando Mendiburu Zevallos, Luis Bravo, Prashant Khare
Presenter: René Sebastian Valencia Ramírez
doi://10.26678/ABCM.COBEM2023.COB2023-0815
Abstract
Understanding the dynamics of premixed flames that propagates in closed channels is important in a wide range of applications, including those involving the development of detonation waves in confined regions. The study of premixed flames propagating in a tube covers a variety of complexities related to flame ignition, laminar flame development, and flame interaction with walls. Accordingly, to study the dynamics of premixed flames propagating in closed channels, numerical simulations of propagation of distorted tulip flames are carried out in this work. All the numerical simulations are performed using the open-source computational tool PeleC, which is part of the Exascale Computing Project (ECP). More specifically, the fully reactive compressible Navier – Stokes equations are solved here using the high-order method PPM (Piecewise Parabolic Method) developed by Colella and Woodward (1984). A 21-step chemical kinetic mechanism is employed to model the chemical reactions and the energy release in a stoichiometric air/hydrogen mixture. Computational mesh independence studies are carried out in this work by both refining grid elements and employing different levels of adaptive mesh refinements (AMR). The final mesh employed here features an element size of 1/96 cm with 4 levels of refinement performed based on density gradients. The main results show that the classic tulip flame evolves into a distorted one. Indeed, two consecutive collapses on the flame front are observed, which are related to wave pressure and presence of reverse flow. Important aspects of the flame formation and propagation process analyzed include: (i) the initial evolution of the tulip flame and its comparison with previous experimental and analytical results, (ii) propagation of acoustic waves and its influence on flame evolution, and (iii) the formation of distorted tulip flame and collapse of flame cups. It is particularly found that the pressure wave produced by the contact of the flame skirt with the side walls reduces the flame velocity and contributes to the formation of tulip flames. This is consistent with the reduction in flame area and the pressure gradient at the flame tip. Furthermore, the collapse of flame cups is associated with the vortex’s formation near the side walls and the increase of pressure waves.
Keywords
Premixed flame, tulip flame, distorted tulip flame, Flame formation and propagation, AMR
