12,000

We have over 12,000 students, from over 100 countries, within one of the safest campuses in the UK

93%

93% of Lancaster students go into work or further study within six months of graduating

Home > Research > Publications & Outputs > Large-eddy simulations of unsteady hydrogen ann...
View graph of relations

« Back

Large-eddy simulations of unsteady hydrogen annular flames

Research output: Contribution to journalJournal article

Published

Associated organisation

Journal publication date10/07/2013
JournalComputers & Fluids
Volume80
Number of pages12
Pages429–440
Early online date30/01/12
Original languageEnglish

Abstract

Large-eddy simulation (LES) of three-dimensional non-premixed hydrogen flames in a confined annular configuration has been conducted in order to clarify the interactions between different instabilities and swirling motion in the reacting jet flow field. The LES approach in parallel implementation follows a dynamic k − Δ subgrid-scale (SGS) model in which the SGS stress is modelled by the eddy viscosity hypothesis using the sub-grid scale turbulent kinetic energy. The results show a geometric central recirculation zone because of the bluff body configuration and a near-wall recirculation region for all the cases considered. The swirling flames also developed a toroidal recirculation zone with a collar-like shear structure around it that ended up in a vortex-breakdown bubble (VBB) for the case of moderate swirl number. As the degree of swirl was increased, the VBB increased in size and strengthened up to create a large central recirculation zone. It was shown that these regions with flow reversal enhance the air and fuel mixing and thus, improve the entire combustion process.