Effect of hydrogen enrichment on the dynamics of a lean technically premixed elevated pressure flame

Chterev, Ianko; Boxx, Isaac

doi:10.1016/j.combustflame.2020.10.033

Cited by 72 publications

(42 citation statements)

References 36 publications

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“…Recently, the effects of hydrogen enrichment on the dynamics of the flame (heat release distribution, combustion instability characteristics, and flow dynamics) for varying conditions of pressure and H 2 volume fractions (up to 50%) were studied experimentally [83,84]. Results showed that hydrogen enrichment leads to a shortening of the flame length and causes the transition from an M-shaped to a V-shaped flame.…”

Section: Preccinstamentioning

confidence: 99%

Recent Combustion Strategies in Gas Turbines for Propulsion and Power Generation toward a Zero-Emissions Future: Fuels, Burners, and Combustion Techniques

et al. 2021

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The effects of climate change and global warming are arising a new awareness on the impact of our daily life. Power generation for transportation and mobility as well as in industry is the main responsible for the greenhouse gas emissions. Indeed, currently, 80% of the energy is still produced by combustion of fossil fuels; thus, great efforts need to be spent to make combustion greener and safer than in the past. For this reason, a review of the most recent gas turbines combustion strategy with a focus on fuels, combustion techniques, and burners is presented here. A new generation of fuels for gas turbines are currently under investigation by the academic community, with a specific concern about production and storage. Among them, biofuels represent a trustworthy and valuable solution in the next decades during the transition to zero carbon fuels (e.g., hydrogen and ammonia). Promising combustion techniques explored in the past, and then abandoned due to their technological complexity, are now receiving renewed attention (e.g., MILD, PVC), thanks to their effectiveness in improving the efficiency and reducing emissions of standard gas turbine cycles. Finally, many advances are illustrated in terms of new burners, developed for both aviation and power generation. This overview points out promising solutions for the next generation combustion and opens the way to a fast transition toward zero emissions power generation.

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Section: Preccinstamentioning

confidence: 99%

Recent Combustion Strategies in Gas Turbines for Propulsion and Power Generation toward a Zero-Emissions Future: Fuels, Burners, and Combustion Techniques

et al. 2021

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“…The values of corr(S r , κ m ) and corr(S n , κ m ) are reported in Table 11. ω c is independent of curvature and thus, according to Equation (8) the correlation between S r and κ m is governed by the correlation between |∇c| and κ m . However, this statement is rendered invalid in the case of DC, where there might be a significant correlation between .…”

Section: Curvature and Tangential Strain Rate Effects On Local Displacement Speed And Its Componentsmentioning

confidence: 99%

“…The ever-growing computing power is an enabler for two trends in recent combustion DNS research: Firstly (not discussed here but underlining the importance of combustion DNS), the availability of high-fidelity datasets has given a significant boost to the development of turbulence and combustion models using machine learning methods [5] and secondly detailed chemical kinetic mod-els for larger and larger hydrocarbon and oxygenated hydrocarbon molecules are being produced [6]. While practical fuels for transportation often contain thousands of distinct chemical compounds [7], there is also an increasing interest in simple fuels such as hydrogen [8,9] or syngas [10,11] that could play an important role during the transition of the fuel landscape. Their main components such as H 2 , CO and CH 4 are conceptually at the base of detailed chemical reaction mechanisms that describe much more complex hydrocarbon combustion [12].…”

Section: Introductionmentioning

confidence: 99%

Comparison of Flame Propagation Statistics Based on Direct Numerical Simulation of Simple and Detailed Chemistry. Part 2: Influence of Choice of Reaction Progress Variable

et al. 2021

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Flame propagation statistics for turbulent, statistically planar premixed flames obtained from 3D Direct Numerical Simulations using both simple and detailed chemistry have been evaluated and compared to each other. To achieve this, a new database has been established encompassing five different conditions on the turbulent combustion regime diagram, using nearly identical numerical methods and the same initial and boundary conditions. The discussion includes interdependencies of displacement speed and its individual components as well as surface density function (i.e., magnitude of the reaction progress variable) with tangential strain rate and curvature. For the analysis of detailed chemistry Direct Numerical Simulation data, three different definitions of reaction progress variable, based on and mass fractions will be used. While the displacement speed statistics remain qualitatively and to a large extent quantitatively similar for simple chemistry and detailed chemistry, there are pronounced differences for its individual contributions which to a large extent depend on the definition of reaction progress variable as well as on the chosen isosurface level. It is concluded that, while detailed chemistry simulations provide more detailed information about the flame structure, the choice of the reaction progress variable definition and the choice of the resulting isosurface give rise to considerable uncertainty in the interpretation of displacement speed statistics, sometimes even showing opposing trends. Simple chemistry simulations are shown to provide (a) the global flame propagation statistics which are qualitatively similar to the corresponding results from detailed chemistry simulations, (b) remove the uncertainties with respect to the choice of reaction progress variable, and (c) are more straightforward to compare with theoretical analysis or model assumptions that are mostly based on simple chemistry assumptions.

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“…Self-excited thermoacoustic instabilities are recognized to occur with coupled unsteady heat release and combustor acoustics (Huang and Yang, 2009). For partially premixed methane/air flames, there are extensive experimental and numerical studies about self-excited oscillations (Allison et al, 2013;Stöhr et al, 2017;Murugesan et al, 2018;Chterev and Boxx, 2021), which revealed that equivalence ratio fluctuations and velocity perturbations are two key factors triggering the thermoacoustic feedback loop individually or simultaneously. Oberleithner et al (2015) concluded the essential impact of processing vortex core on the random transition between V-and M-shape flames.…”

Section: Introductionmentioning

confidence: 99%

Effect of Hydrogen and Ammonia Addition on Self-Excited Thermoacoustic Instabilities of Partially Premixed Methane/Air Flames

Shi¹,

Lian²,

Liu³

et al. 2022

Proceedings of Global Power &Amp; Propulsion Society

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The pressing need to realize carbon neutrality in gas turbine applications has recently led to a new wave of research on low-carbon energy alternatives, among which hydrogen and ammonia, as carbon-free fuels, have attracted great attention. This work studies the impact of hydrogen or ammonia addition on combustion instability characteristics of partially premixed methane/air flames. Bifurcation behaviors of the low-frequency thermoacoustic system (around 100 Hz) are experimentally identified and explored by decreasing global equivalence ratios (ϕ) from 0.7 to 0.45 at a fixed Reynolds number (Re = 10,000). Three different fuel cases are selected for comparative analysis, namely 100% methane (100M), 75%-25% (vol) methane-hydrogen (75M25H) and methane-ammonia (75M25A) blends. High-speed diagnostics and acoustic measurements are conducted to resolve different flame dynamics and thermoacoustic characteristics. The results show that co-firing methane with hydrogen or ammonia has significant impacts on thermoacoustic bifurcation behaviors and flame dynamics. For the 100M case, a clear mode switch occurs at ϕ = 0.63-0.61 from a low-amplitude limit cycle with a relatively higher frequency (Regime I) to a high-amplitude one with a relatively lower frequency (Regime II), while the mode transition point moves downward to ϕ = 0.59-0.52 with 25% hydrogen addition. Distinctively, no mode transition is observed with 25% ammonia addition, showing purely Regime II within the studied range of ϕ. Besides, the dominant frequency increases with hydrogen addition but decreases with ammonia addition. The three cases show roughly identical flame motions, exhibiting a rapid-extinction-slow-recovery process in the period of combustion oscillation. However, the flame intensity notably strengthens with hydrogen addition but weakens with ammonia addition and phase delay.

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Effect of hydrogen enrichment on the dynamics of a lean technically premixed elevated pressure flame

Cited by 72 publications

References 36 publications

Recent Combustion Strategies in Gas Turbines for Propulsion and Power Generation toward a Zero-Emissions Future: Fuels, Burners, and Combustion Techniques

Recent Combustion Strategies in Gas Turbines for Propulsion and Power Generation toward a Zero-Emissions Future: Fuels, Burners, and Combustion Techniques

Comparison of Flame Propagation Statistics Based on Direct Numerical Simulation of Simple and Detailed Chemistry. Part 2: Influence of Choice of Reaction Progress Variable

Effect of Hydrogen and Ammonia Addition on Self-Excited Thermoacoustic Instabilities of Partially Premixed Methane/Air Flames

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