Poster De Conférence Année : 2025

Large Eddy Simulations of multi-component swirling-spray flames' dynamics under acoustic oscillations

Résumé

Well-understanding and mastering Sustainable Aviation Fuels (SAF) composition, as well as the impact of their initial component concentrations on flame dynamics, is of critical importance in today’s energy transition and safe operability context. In this study, the focus lies on conducting Large Eddy Simulations (LES) to understand the impact of species concentration changes in well-controlled multi-component fuel blends on flame dynamics under forced acoustic oscillations. To do so, the SICCA-spray rig from the EM2C laboratory, operated with two blends of n-dodecane and n-heptane in varying proportions, is specifically addressed in light of available data. While LES successfully capture key trends, phase lag predictions and absolute time delays are found to deviate from experimental flame transfer function measurements but remain within the correct order of magnitude. Across the two investigated blends, results suggest that increasing the proportion of n-heptane enhances flame dynamics, particularly in terms of heat release rate fluctuations and spray penetration length oscillations. Higher proportions of n-heptane promote faster evaporation, increasing the local equivalence ratio and, consequently, the flame response to acoustic perturbations. In contrast, blends with more n-dodecane lead to longer characteristic times with extended evaporation and combustion delays, reducing the amplitude of the flame dynamics. Close to the injector exit, n-heptane exhibits greater spatial fluctuations modulated via variations in the inner recirculation zone size. During an oscillation, the latter is observed to deflect the flame/flow opening angle by up to 50% relative to values obtained under steady-state conditions. Ultimately, these effects are closely tied to the evaporation properties of each fuel and their concentration proportions within the blend. This insight highlights the intricate relationship between fuel properties, their ratios within blends, and the resulting flame dynamics, shedding light on the complexities of multi-component fuel combustion and thermo-acoustic instabilities.

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Dates et versions

hal-05052809 , version 1 (30-04-2025)

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Identifiants

  • HAL Id : hal-05052809 , version 1

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N Sekularac, A Dupuy, L Gicquel. Large Eddy Simulations of multi-component swirling-spray flames' dynamics under acoustic oscillations. European Combustion Meeting 2025, Apr 2025, Edinburgh, United Kingdom. ⟨hal-05052809⟩
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