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Three dimensional measurements of surface areas and burning velocities of turbulent spherical flames

Accepted version
Peer-reviewed

Type

Article

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Authors

Lawes, M 
Hochgreb, S 
Nivarti, GV 

Abstract

Measurements of 3D turbulent flame surface area and burned gas were carried out for spherically expanding flames in different methane-air and hydrogen-air mixtures using a high frequency swinging laser sheet technique based on Mie scattering. The corresponding turbulent burning velocities were measured simultaneously using the rate of pressure rise, at turbulence rms velocities between 0.3 and 2.0 m/s. The ratio of turbulent burning velocity enhancement 𝑢𝑡𝑚⁄𝑢𝑙 to flame surface area enhancement 𝐴3𝐷/𝑎3𝐷 was measured as a function of turbulence rms velocity. For the methane-air flames, the turbulent burning velocity enhancement is close to that of the flame surface area enhancement. For the hydrogen-air flames, the former can exceed the latter by a factor of up to 6 at the largest values of turbulence rms velocity tested. The large discrepancy suggests that in the case of hydrogen-air flames, the measured rate of burning per unit flame area is significantly enhanced by the turbulence. For the reconstructed 𝐴3𝐷/𝑎3𝐷, the corresponding 𝐴2𝐷/𝑎2𝐷 are also discussed.

Description

Keywords

3D, Flame surface areas, Turbulent spherical flames, Swinging laser sheet technique, Turbulent burning velocity, Damkohler's first hypothesis

Journal Title

Combustion and Flame

Conference Name

Journal ISSN

0010-2180
1556-2921

Volume Title

233

Publisher

Elsevier BV
Sponsorship
Engineering and Physical Sciences Research Council (EP/P022286/1)
EP/P022286/1.