Work

Exploring liquid fuel combustion dynamics in a swirl burner using dynamic mode decomposition

Year: 2025

Type: article

Abstract: Aero gas turbine engine combustors are transitioning from traditional Rich-Quench-Lean (RQL) staging to Lean Premixed Prevaporized (LPP) operation to reduce harmful NOx emissions and improve combustion efficiency. This operational shift, however, introduces the risk of thermoacoustic instabilities, a significant concern for reliable operation and integrity of the jet fuel fired aero gas turbines. Moreover, the complex geometries of aero engine combustors and the challenges of partially premixed conditions further complicate stability analysis and demand advanced diagnostic techniques. To that end, this work aims to analyse thermoacoustic and swirl burner instabilities of our in-house designed Magister burner under engine representative lean conditions using Detached Eddy Simulation. We extended our prior analysis by applying Dynamic Mode Decomposition (DMD) in a distributed computing environment, leveraging our PARAMOUNT modal analysis package, to capture the burner's critical acoustic and transient dynamics. The proposed novel DMD combined spectrum effectively identified the mechanism driving vortex core rotation, capturing its frequency to within 1% of the measured value. It was demonstrated that using Proper Orthogonal Decomposition (POD) modes directly is more effective than an exact DMD formulation, yielding a 44% reduction in the Mean Absolute Error (MAE) of DMD predicted temperature values. Furthermore, the application of variable stacking reduced the MAE of the short-term DMD temperature predictions by 40%. Finally, an MRDMD adjustment is proposed that leverages a critical Strouhal number (St = 0.6) to significantly enhance ROM by ensuring essential flow dynamics are retained. This novel analysis framework demonstrates a powerful capability to assess thermoacoustic stability, extracting critical physical insights from complex simulations that produce large datasets and thereby accelerating the design cycle for aero-engine combustors.

Source: Engineering Applications of Computational Fluid Mechanics

DOI: 10.1080/19942060.2025.2557009

Authors: Alireza Ghasemi, Jim B. W. Kok

Institution: University of Twente

Language: English

Topic: Combustion and flame dynamics

Subfield: Computational Mechanics

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: gold

Estimated APC paid: $1,993