Stage M2 – Hydrogen-air flame as a source of sound

In order to mitigate the climate crisis effects, Hydrogen is currently being considered as a substitute fuel for aircraft engines and heavy duty land based motors. This substitution would lead practical systems to burn fuel lean mixtures with air, which combustion process is known to be intrinsically unstable. These combustion instabilities may lead to acoustic coupling, which may be harmful to the combustor performance and integrity.

This study aims to experimentally characterise the acoustic behaviour of the ANÔ burner under different operating conditions. The challenge is to identify the acoustic sources and to separate the facility from the combustion induced noises. Time-resolved Schlieren flame imaging will be investigated as a means to infer the fluctuating temperature gradient, and thus of characterizing the fluctuating heat release rate. This characterization will then be used in the framework of Lighthill’s analogy to model the far-field emitted sound. Results of this calculation will be compared to results of microphonic measurements to validate the physical model.

This work will be co-supervised by researchers of the combustion (CT) and acoustical (2AT) teams of Pprime. Overall, the proposed work has both experimental and theoretical components; also it is multidisciplinary (acoustics and combustion). Candidates must therefore have a keen scientific curiosity, and should be aware that working in a research laboratory requires autonomy and rigor.

More informations on the link below.