High-order mesh-free direct numerical simulation of lean hydrogen flames in confined geometries

H. M. Broadley; S. J. Lind; J. R. C. King

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arXiv · 2503.16951

High-order mesh-free direct numerical simulation of lean hydrogen flames in confined geometries

H. M. Broadley·S. J. Lind·J. R. C. King

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Abstract

Here we perform the first analysis of high-fidelity simulations of the propagation of lean hydrogen flames through porous media, taking cylindrical arrays a representative example geometry. In this fundamental study we discuss the impact of confinement on both thermodiffusive and thermoacoustic instabilities. Flame propagation in these complex geometries is cannot be performed by leading mesh-based codes, and is instead simulated using a high-order meshfree method, LABFM. Pore scale propagation is shown to be dependent on throat width between cylinders, and this is then related to large-scale flame dynamics, allowing us to give a heuristic explanation for the increased growth rate of the thermodiffusive instability in more confined geometries. Thermoacoustic instabilities are also observed for sufficiently confined geometries. Understanding these instability mechanisms is crucial for improving the design of future combustors, both in terms of controlling flame dynamics and increasing the durability of combustors.

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H. M. Broadley, S. J. Lind, J. R. C. King. 2025-03-21. High-order mesh-free direct numerical simulation of lean hydrogen flames in confined geometries. https://arxiv.org/abs/2503.16951

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