Xie, Y., Elsayed Morsy, M. and Yang, J. orcid.org/0000-0003-4401-8061 (Cover date: 1 December 2023) Self-Acceleration and global pulsation of unstable laminar Hydrogen-Air flames. Fuel, 353. 129182. ISSN 0016-2361
Abstract
The self-acceleration and global pulsation of spherically expanding laminar hydrogen-air flames were studied in a spherical explosion vessel, over a wide range of equivalence ratios (0.4–2.0), initial temperatures (300–400 K), and initial pressures (0.1–0.7 MPa). Comprehensive quantitative data on the self-acceleration propagation of unstable laminar hydrogen-air flames were obtained. The results show that the self-similarity appears after the onset of instability, and the previous assertion of acceleration exponent α = 1.5 is not valid for hydrogen-air flames. The derived values of α for such flames vary from 1.125 and 1.39 in the present work. For the selfaccelerating flame, the temporal evolution of the flame radius is described by ru = Atα, and temporal flame propagation speed is described by Sn = Aαt α− 1. A modified theoretical expression of the constant A is proposed and validated against the present experimentally derived results. The acceleration phase after flame instability presents a global pulsating acceleration pattern. The frequency of global pulsation rises as the pressure or temperature of the flame increases. A pulsing flame speed equation can be used to reliably estimate flame speed after the onset of cellular instability. Self-acceleration observed in small laboratory explosions can serve as a predictive indicator for flame behaviour on a larger atmospheric scale.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2023 The Authors. This is an open access article under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. |
Keywords: | Spherically expanding flame, Self-similarity, Acceleration exponent, Global pulsation |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mechanical Engineering (Leeds) > Institute of Engineering Thermofluids, Surfaces & Interfaces (iETSI) (Leeds) |
Funding Information: | Funder Grant number EPSRC (Engineering and Physical Sciences Research Council) EP/R511717/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 20 Jul 2023 09:11 |
Last Modified: | 20 Jul 2023 09:11 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.fuel.2023.129182 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:201707 |