CUED Publications database

Investigation of flame stretch in turbulent lifted jet flame

Ruan, S and Swaminathan, N and Mizobuchi, Y (2014) Investigation of flame stretch in turbulent lifted jet flame. Combustion Science and Technology, 186. pp. 243-272. ISSN 0010-2202

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DNS data of a laboratory-scale turbulent lifted hydrogen jet flame has been analyzed to show that this flame has mixed mode combustion not only at the flame base but also in downstream locations. The mixed mode combustion is observed in instantaneous structures as in earlier studies and in averaged structure, in which the predominant mode is found to be premixed combustion with varying equivalence ratio. The non-premixed combustion in the averaged structure is observed only in a narrow region at the edge of the jet shear layer. The analyzes of flame stretch show large probability for negative flame stretch leading to negative surface averaged flame stretch. The displacement speed-curvature correlation is observed to be negative contributing to the negative flame stretch and partial premixing resulting from jet entrainment acts to reduce the negative correlation. The contribution of turbulent straining to the flame stretch is observed to be negative when the scalar gradient aligns with the most extensive principal strain rate. The physics behind the negative flame stretch resulting from turbulent straining is discussed and elucidated through a simple analysis of the flame surface density transport equation. © 2014 Copyright Taylor and Francis Group, LLC.

Item Type: Article
Divisions: Div A > Energy
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:06
Last Modified: 23 Nov 2017 03:59