In this paper, it is shown that prior to flashback, small dynamical changes appear in the system. These changes appear as a drift in the recurrence plots and are found to be associated with a gradual increase in the determinism and recurrence rate. Thus, this study indicates that precursors to flame flashback exist and can be detected in the multidimensional phase space reconstructed from pressure measurements acquired during flashback. This observation could have broad academic as well as industrial implications.
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ACS Omega
April 2024
Mechanical Engineering Department and Interdisciplinary Research Center for Hydrogen Technologies and Carbon Management (IRC-HTCM), King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia.
Hydrogen (H) enrichment is a viable solution to deter the early blowout of oxy-fuel flames at high CO dilution levels and to enhance combustor turndown in the supercritical-CO cycles of zero-emission power plants. This was already implemented successfully in a previous study by the author, where H was premixed with the oxy-reactants upstream of the burner headend in a fully premixed flame stabilized on a micromixer-like burner. The micromixer technology is known for its superior flame stability and inherent fuel/oxidizer flexibility.
View Article and Find Full Text PDFEntropy (Basel)
May 2021
Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
When operating under lean fuel-air conditions, flame flashback is an operational safety issue in stationary gas turbines. In particular, with the increased use of hydrogen, the propagation of the flame through the boundary layers into the mixing section becomes feasible. Typically, these mixing regions are not designed to hold a high-temperature flame and can lead to catastrophic failure of the gas turbine.
View Article and Find Full Text PDFAppl Spectrosc
June 2017
Combustion Physics, Lund University, Sweden.
Spatially and temporally resolved measurements are of great importance in turbulent premixed flame studies, especially when investigating rapid processes such as when flame local extinction, re-ignition, or flashback occur in a reacting flow. Here, an experimental approach for simultaneously probing two different species at high frame rates (50 kHz) is presented by employing a multi-YAG laser system. The laser radiation at 355 nm generated by a multi-YAG laser system was split into two beam paths: one beam for exciting formaldehyde and the other for pumping an optical parametric oscillator (OPO).
View Article and Find Full Text PDFChaos
January 2016
School of Engineering, University of Glasgow, Glasgow, United Kingdom.
In this paper, it is shown that prior to flashback, small dynamical changes appear in the system. These changes appear as a drift in the recurrence plots and are found to be associated with a gradual increase in the determinism and recurrence rate. Thus, this study indicates that precursors to flame flashback exist and can be detected in the multidimensional phase space reconstructed from pressure measurements acquired during flashback.
View Article and Find Full Text PDFPhys Rev E Stat Nonlin Soft Matter Phys
January 2010
Laboratoire de Combustion et de Détonique, UPR 9028 du CNRS, ENSMA, Futuroscope Cedex, Poitiers, France.
The dynamics of two-dimensional thin premixed flames is addressed in the framework of mathematical models where the flow field on either side of the front is piecewise incompressible and vorticity free. Flames confined in channels with asymptotically straight impenetrable walls are considered. Besides a few free propagations along straight channels, attention is focused on flames propagating against high-speed flows and positioned near a round central obstacle or near two symmetric bumps protruding inward.
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