Work

Thermoacoustic FEM modeling of partly autoignition and propagation-stabilized flames

Year: 2025

Type: article

Abstract: This paper describes a methodology to thermoacoustically account for different flame types in a single Finite-Elementcomputation. To do so, the flame segmentation mechanism presented in previous studies is used to characterize the different flame zones. Differentiation is done between propagation-stabilized shear-layer flames and autoignition flames that respond to acoustic perturbations very differently. While autoignition flames mainly respond to acoustic pressure and temperature fluctuations, propagation-stabilized flames respond to acoustic velocity perturbations. Thus, flame transfer functions specific to each flame type are analytically implemented within the frequency domain Finite-Elementcomputation. Using the novel framework, it is shown that the global FTF obtained from Computational-Fluid-Dynamics (CFD) simulations of a backward facing step reheat combustor can be reproduced accurately in the low-frequency regime for an operating point where the flame is forced in a planar manner. The investigated operating point operates on hydrogen fully premixed at lean and autoignitive conditions. The autoignition framework is validated by comparison to one-dimensional direct-numerical-simulation (DNS). The time averaged CFD heat release rate result is validated with large eddy simulation (LES) data.

Source: Zürcher Hochschule für Angewandte Wissenschaften digital collection (Zurich University of Applied Sciences)

DOI: 10.21256/zhaw-34241

Authors: Heinzmann, Simon M., Leder, Nino A., Gopalakrishnan, Harish S., Bothien, Mirko R.

Language: English

Topic: Combustion and flame dynamics

Subfield: Computational Mechanics

Field: Engineering

Domain: Physical Sciences

Open Access status: green

OpenAlex ID: W7084613714

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