Nivarti, G orcid.org/0000-0002-8326-1147 and Cant, S (2017) Direct Numerical Simulation of the bending effect in turbulent premixed flames. Proceedings of the Combustion Institute, 36 (2). pp. 1903-1910. ISSN 1540-7489
Abstract
In turbulent premixed flames, much experimental evidence points to a strong influence of pre-mixture turbulence intensity on the turbulent burning velocity. The linear enhancement of turbulent burning velocity in low-intensity turbulence is predicted accurately by current models. In contrast, the deviation from linearity in high-intensity turbulence, known as the “bending effect,” remains to be explained. The present work has employed Direct Numerical Simulation (DNS) to investigate the bending effect. An initially laminar methane-air premixed flame was subjected to increasing levels of turbulence across five different simulations which maintained all parameters except the turbulence intensity constant. The bending effect was captured within these simulations. Subsequently, plausible explanations were investigated using the framework of the Flame Surface Density (FSD) approach. From the ensuing analysis, it is evident that flame surface area reflects distinctly the variation of turbulent burning velocity with turbulence intensity. Local flame quenching does not appear to be the primary mechanism behind the bending effect. Instead, the observed bending effect results from a shift in balance, under high-intensity turbulence, towards mechanisms that favour destruction of flame surface area. These mechanisms tend to preserve the reaction layer and, thereby, ensure the validity of Damköhler’s hypothesis and flamelet models in conditions that cause the bending effect that is observed here to occur.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Keywords: | Turbulent premixed flames; The bending effect; Direct Numerical Simulation; High-intensity turbulence |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mathematics (Leeds) > Applied Mathematics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 06 Aug 2020 09:48 |
Last Modified: | 06 Aug 2020 09:48 |
Status: | Published |
Publisher: | Elsevier BV |
Identification Number: | 10.1016/j.proci.2016.07.076 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:164011 |