Review of laboratory swirl burners and experiments for model validation

Swirl combustion, whether of gaseous fuels or sprays, forms the basis of many thermal power generation systems and to effective design and optimisation of these complex systems has benefited from the development of reliable computational design tools which employ advanced modelling guided by measurements. Laboratory-scale burners which reduce the scale of the investigative challenge but retain the underlying fundamental behaviours associated with full- or pilot-scale set-ups play a key role in these advances. Such laboratory-scale burner platforms must embody essential phenomena present in full-scale systems such as the formation of primary and secondary recirculation zones. They must also span a dynamic operating envelope which allows the initiation of multi-modal (time varying) instabilities over a range of flame stabilization regimes. This paper presents a fixed-scope overview of experimental works on laboratory-scale swirl flame burners where significant reporting of results or data bases exists. The study focuses on selected gaseous fuel burners that span premixed, partially premixed and non-premixed combustion over unconfined and confined conditions. Whilst this is by no-means a comprehensive (topical) review into swirl combustion, it is aimed at guiding interested researchers in navigating a way through the vast literature published on laboratory-based swirl burners. These configurations typically encompass highly resolved flow- and/or compositional-fields derived from non-intrusive laser diagnostics. In addition to time-averaged flow-fields, measured data also typically includes flame stability/structure characteristics (flame shape/blow- or lift-off) as well as combustion instabilities. The paper draws upon a wide body of knowledge to summarise the current understanding of the effects of swirl and confinement on flow behaviour, emission characteristics, flame stabilization, and flow instability in laboratory-scale swirl burners. (C) 2015 Elsevier Inc. All rights reserved.