DNS Analysis of Wall Heat Transfer and Combustion Regimes in a Turbulent Non-premixed Wall-jet Flame
2016 (English)In: Flow Turbulence and Combustion, ISSN 1386-6184, E-ISSN 1573-1987, 1-19 p.Article in journal (Refereed) PublishedText
Understanding the heat-release effects on the wall heat transfer in turbulent reacting flows, i.e. heat transfer with or without significant density variation, is essential for a wide variety of industrial flows, especially combustion problems. The present study focuses on the wall heat transfer and the near-wall reaction characteristics. The heat-release effects on the wall heat transfer and skin-friction coefficients are investigated using three-dimensional direct numerical simulations of a turbulent reacting wall-jet flow with and without heat release. Reductions in the skin-friction coefficient are observed in the exothermic case, compared to the isothermal one, and the underlying mechanism is explained. The absolute wall heat flux also increases, while the corresponding Nusselt number decreases with increasing heat release. Furthermore, the wall effects on the near-wall average burning rate are assessed. It is found that the isothermal cold wall results in an appreciable decrease of the burning rate in the exothermic cases. We observed indications that the wall increases the chances for the development of the premixed mode and its occurrence is very fast in the wall-normal direction.
Place, publisher, year, edition, pages
Springer Netherlands, 2016. 1-19 p.
Direct numerical simulation, Flame index, Non-Premixed combustion, Skin friction coefficient, Turbulent wall-jet, Wall heat transfer, Combustion, Friction, Heat flux, Isotherms, Jets, Numerical models, Skin friction, Tribology, Nonpremixed combustion, Turbulent wall jet, Heat transfer
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-188292DOI: 10.1007/s10494-016-9716-7ScopusID: 2-s2.0-84957556460OAI: oai:DiVA.org:kth-188292DiVA: diva2:935424
QC 201606102016-06-102016-06-092016-06-10Bibliographically approved