In this 13-part series of articles, The Combustion Institute recognizes the 2023 Distinguished Papers selected from among the scientific papers presented during the 39th International Symposium on Combustion. Congratulations to Eirik Æsøy, Girish K. Jankee, Srikar Yadala, Nicholas A. Worth, and  James R. Dawson for winning the DPA in the Propulsion colloquium.

Dr. Æsøy and the members of his team authored their distinguished paper, “Suppression of self-excited thermoacoustic instabilities by convective-acoustic interference,” to study the challenges posed by burning hydrogen as a zero-carbon substitute for natural gas in gas turbines. There are interesting research problems associated with this particular study that are technically important. For approximately the last six years, the team worked with the gas turbine industry in Europe.

There has always been a crucial development issue for gas turbines. Instabilities – either combustion or thermoacoustic – occur when the fluctuations in the heat release rate couple with the acoustics of the combustion chamber. Drs. Æsøy, Jankee, Yadala, Worth, and Dawson wanted to understand the impact of increasing the mass fraction of hydrogen in hydrogen-methane mixtures and pure hydrogen on combustion instabilities.

The team states that their studies are particularly exciting because the approach is simple. By introducing controlled vortex shedding into the flow upstream of the flame, the aforementioned instabilities can be suppressed. When the relative convection time of the vortices is carefully tuned, the flame dynamics and the acoustics can be decoupled via cancellation and ensure stable operation over a wide range of operating conditions.

The impact of the findings of the Propulsion group are both immediate and long-term. Dr. Æsøy and his team have shown that even small geometric features in burner geometries can play an important role in combustion instabilities, but if they are carefully designed, they can be used to prevent combustion instabilities. It is important to add, per Dr. Æsøy, that although these results are really promising, the true impact of the approach needs to be extended to the complex burner geometries. A number of researchers in the gas turbine industry have reached out to these researchers regarding this topic.

When asked about the benefits of their studies, this research team stated that the main beneficiaries are the gas turbine industry for both power and aviation. Combustion instabilities are frequently a hindrance in engine development and their work shows that one could potentially introduce small geometry changes to suppress them.

This research was done in the combustion lab of the thermo fluids research group in Trondheim, Norway at the Norwegian University of Science and Technology (NTNU). The paper builds on research performed during the main author’s PhD research from 2018-2022. The effort put into the present paper was initiated during the spring of 2021 and was finalized during the submission process to the 39th International Symposium on Combustion.

Over 1,500 papers were submitted to the 39th International Symposium on Combustion. All papers were categorized into one of 13 colloquia, and then distributed to Colloquium Coordinators and Co-Chairs. Each paper received at least three reviews from qualified individuals through the peer-review process. Less than 50 percent of the papers submitted were accepted for presentation.

Following the symposium, one paper presented in each colloquium is awarded the distinction of Distinguished Paper. Visit here to view the presentation. The 13 Distinguished Papers undergo committee review for consideration for the Silver Combustion Medal. A paper selected for this honor exemplifies quality, achievement, and significance to advance a field of combustion science, and will be awarded during the CI’s 40th International Symposium – Emphasizing Energy Transition in Milan, Italy.