Title: Flame dynamics in sub-millimetre combustors

Authors: Shaurya Prakash, Adrian D. Armijo, Richard I. Masel, Mark A. Shannon

Addresses: Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign, 1206 W Green Street, Urbana, IL 61801, USA. ' Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign, 981 Grand Canyon Parkway #316, Hoffman Estates, IL 60194, USA. ' Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S Mathews, Urbana, IL 61801, USA. ' Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign, 1206 W Green Street, Urbana, IL 61801, USA

Abstract: This paper describes experimental observations of flame dynamics within an alumina non-premixed combustor with a sub-millimetre (0.75 mm) minimum size. These flame dynamics occur within a total combustor volume of 130 mm³ and are imaged through a sapphire window. The confined flames are surveyed using visual still-frames, high-speed flame imaging, measurement of external wall temperatures, and recordings of acoustic emissions from the combustor. The observed flame dynamics are characterised by an oscillating edge-flame that is anchored at the combustor inlet and is accompanied by ignition/extinction events leading to the eventual formation of a stable edge-flame and distinct cellular structures along the reaction channel. This paper investigates the unstable and unsteady flame dynamics within the non-premixed sub-millimetre combustors from ignition to the formation of stable flame structures.

Keywords: alumina Al₂O₃; microcombustion; edge flame; non-premixed combustors; flame cells; methane; instability; transient; flame structure; non-stabilised flames; combustion; flame dynamics; sub-millimetre combustors.

DOI: 10.1504/IJAP.2007.013023

International Journal of Alternative Propulsion, 2007 Vol.1 No.2/3, pp.325 - 338

Published online: 03 Apr 2007 *

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