Session: 04-25 Combustion Dynamics - Hydrogen Flames I

Paper Number: 152971

Thermoacoustic Instabilities in Hydrogen-Methane Combustion: Analysis of Self-Excited Flame Dynamics in a Lab-Scale Cyclone Burner 

The transition to hydrogen as a fuel is crucial for reducing carbon emissions in industrial
combustion processes, but it presents challenges in maintaining combustion stability. This study
examines the flame dynamics and thermoacoustic instabilities in a 30 kW cyclone burner
system, using methane-hydrogen blends with hydrogen volume fractions ranging from pure
methane to 80% hydrogen. The cyclone burner imparts a swirling motion to the airflow, which is
then premixed with fuel in the annular passage. Fuel flow excitation is controlled via a siren,
producing sinusoidal waveforms from 50 to 600 Hz range.Pressure oscillations were recorded
using four pressure transducers, while OH chemiluminescence was measured through optical access
windows using a photomultiplier. Flame dynamics were captured by a Phantom VEO 710L highspeed
camera, allowing detailed investigation of the flame’s behavior under varying fuel
compositions. The addition of hydrogen was found to amplify oscillation amplitudes, significantly
influencing the combustion stability.Flame transfer functions (FTFs) were derived and crossvalidated
with data from the IFTA acquisition system, which includes an integrated FTF
calculator. Non-intensified high-speed camera images were processed using spectral proper
orthogonal decomposition (SPOD), offering deep insights into the flame’s physical
characteristics. The SPOD spectra revealed dominant frequencies that strongly correlated with
pressure and heat release rate measurements. Similar trends were observed in SPOD modes
as hydrogen concentrations increased, further highlighting the role of hydrogen in increasing pressure oscillation amplitudes.These findings demonstrate that SPOD-processed visual data is an
effective tool for analyzing flame dynamics and diagnosing thermoacoustic instabilities in
hydrogen-methane combustion systems. The research contributes to the understanding needed
to safely integrate hydrogen into industrial combustion processes while maintaining system
stability.

Presenting Author: Berksu Erkal University of Twente

Presenting Author Biography: He finished his bachelor at METU. He worked as senior propulsion engineer at TUBITAK SAGE for 6 years, then he joined University of Twente for thermoacoustic studies.

Authors:

Berksu Erkal University of Twente
Jim Kok University of Twente