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Detonation of Liquid and Gaseous Mixtures
Published in Kenneth M. Bryden, Kenneth W. Ragland, Song-Charng Kong, Combustion Engineering, 2022
Kenneth M. Bryden, Kenneth W. Ragland, Song-Charng Kong
Large liquid-fueled rocket motors have occasionally experienced wave-like pressure excursions that have been well documented. This type of combustion instability can be very destructive and can rupture the thin-walled rocket motor. While some combustion instability is acoustic in nature and leads to failure due to high heat transfer, there is another failure mode that is detonation-like with accompanying pressure waves. The cure for acoustic instabilities is appropriately designed liners, while the detonation-like instabilities require suitably placed baffles.
Nonlinear Dynamic Analysis of the Transition from MILD Regime to Thermoacoustic Instability in a Reverse Flow Combustor
Published in Combustion Science and Technology, 2022
Atanu Dolai, Santanu Pramanik, Pabitra Badhuk, Ravikrishna RV
To the best of the authors’ knowledge, the transition of combustion dynamics from MILD to combustion instability in a reverse flow combustor has not been reported in the literature. Combustion instability affects the combustor performance, reduces the operating range and combustor lifetime. It arises from the interaction between unsteady heat release and acoustic modes of the combustion chamber, particularly when heat released from the chemical reactions provides energy for driving the acoustic modes (Huang and Yang 2009; Lieuwen 2003). As a result, pressure oscillations from the combustor have high amplitude with a predominant oscillation frequency, which may even lead to the structural failure of the combustor (Lieuwen 2003). The fundamental aspects of self-excited acoustic oscillations and acoustic-flame interaction are reviewed in the seminal work by Lieuwen (Lieuwen 2003), whereas the sensitivity of thermoacoustic oscillations to design parameters have been discussed in a short review by Juniper and Sujith (Juniper and Sujith 2018).
Exploring active subspace for neural network prediction of oscillating combustion
Published in Combustion Theory and Modelling, 2021
Long Zhang, Nana Wang, Jieli Wei, Zhuyin Ren
Meanwhile, considerable researches [14–18] have been reported on developing effective active control means to mitigate combustion instability in industrial devices. For example, McManus et al. [16] reported a 10 dB decrease in the magnitude of the combustion noise when applying approximately 30 W of power to a loudspeaker-driven control actuator for premixed ethylene and air combustion. Barbosa et al. [17] applied local swirling hydrogen injection to actively control combustion instability in an experimental lean premixed combustor. Results showed that hydrogen injection leads to a significant reduction of the pressure oscillation intensity, while the unsteady heat release remains at the same level. The key premise for effective active control is the capability to predict the instability characteristics, which remains challenging in both accuracy and efficiency due to the complex coupling among various physical processes [19–21]. For burning industrial gases, four types of complex oscillating combustion are observed [20,21], resulting from intrinsic mixing/kinetics/heat loss interaction, single inflowing fluctuation, inflowing fluctuation superposition and fuel switching. Efficient nonlinear models are necessary for fast and reliable prediction of key oscillating characteristics for active control.
Computational investigations of the coupling between transient flame dynamics and thermo-acoustic instability in a self-excited resonance combustor
Published in Combustion Theory and Modelling, 2019
Tejas Pant, Chao Han, Haifeng Wang
Combustion instability is an undesirable physical phenomenon observed in many combustion devices ranging from land-based gas turbines used for power generation purposes to high-speed propulsion devices like rocket engines, ramjets and gas turbines. It is characterised by large-amplitude pressure (acoustic) waves propagating back and forth in the combustion chamber of a combustor. The pressure fluctuations give rise to a high level of thermal and mechanical stresses in the critical components of a combustor such as the fuel injectors, the oxidiser post, and the combustor liner. Incessant exposure to such periodic stresses can cause fretting of these components which can ultimately result in a cataclysmic failure of the engine. The underlying physics governing the generation of the thermo-acoustic instability is a complex interaction among heat release, turbulence, and acoustic waves. Currently, our understanding of this highly complicated interaction is limited and it is difficult to predict the conditions under which thermo-acoustic instability can occur. As such, mitigation of combustion instability is still one of the biggest challenges that the aerospace industry is facing after more than a half-century of research [1].