Stationary ethylene–air edge flames in a wedge-shaped region at low and high strain rates. Issue 6 (19th September 2021)

• Record Type: Journal Article
• Authors: Shields, Ben; Freund, Jonathan B.; Pantano, Carlos
• Is Part Of: Combustion theory and modelling. Volume 25:Issue 6(2021)
• Page Start: 1039
• Page End: 1063
• Publication Date: 2021-09-19
• Subjects: edge flame -- ethylene -- detailed chemistry -- eigenvalue problem -- flame speed; Combustion -- Mathematical models -- Periodicals; 541.361
• DOI: 10.1080/13647830.2021.1900921
• Languages: English
• ISSNs: 1364-7830

Abstract

ABSTRACT: Edge flames are a canonical two-dimensional flame structure appearing in lifted jet flames and in the growth and repair of flame holes in nonpremixed turbulent combustion. Computational studies of edge flames with hydrodynamic-coupling at high strains are difficult owing to difficulties defining a stationary state. A wedge-shaped counterflow configuration is here used to provide control over the position of the edge flame, and allowing access to stationary, hydrodynamically-coupled retreating flames (at low and high strains). ethylene–air edge flames are established in the resulting non-uniformly strained counterflow, with combustion modeled using a skeletal reduction of the USC Mech II. The details of the ethylene–air edge flame are discussed, and comparisons are made between stoichiometric, fuel-lean, and fuel-rich compositions. Mixture-fraction-based coordinates local to the flame front are developed and analysed for a range of edge-flame speeds and compositions. A strain-rate parameter is described that admits a speed-strain relationship that is insensitive to the mixture stoichiometry, and a model for retreating flame speeds at high strain rates is discussed.