Sustainable Propulsion & Power

Research explores gas turbine and jet engine combustion, sustainable aviation fuels, rotating detonation engines, ramjet and scramjet combustion, emissions and plasma assisted combustion and optimized thermodynamic cycles to create eco-friendly solutions for aviation, automotive, and energy industries.

Sustainable aviation fuels

Sustainable Aviation Fuels (SAFs) are renewable alternatives to conventional jet fuels, of-fering significant environmental benefits. Produced from biomass, waste oils, municipal solid waste, or synthetic processes using renewable hydrogen and captured carbon diox-ide, SAFs can significantly reduce lifecycle greenhouse gas emissions. SAFs are today "drop-in" fuels, used in blends with fossil jet fuels to facilitate compatibility with existing aircraft engines and infrastructure without requiring modifications. For the future we need to develop SAFs that can be used without blending with fossil jet fuels. Scaling SAF pro-duction involves overcoming challenges like feedstock availability, cost efficiency, and technological advancements. Adoption of SAFs is critical for reducing aviation's environ-mental impact and achieving global net-zero targets.

In this are we lead the competence center, CESTAP (cestap.se), funded by the Swedish Energy Agency, industry and academia together, that focus on sustainable turbine fuels for both electricity and pwer generation and aviation. In addition to CESTAP we participate in three EU projects, MORE & LESS, MYTHOS, CIRCULAR FUELS and one EU-EDF project NEUMANN having the same overall objectives. Together these activities span the full spectrum of SAF related challenges ranging from feedstock conversion to fuel testing, and life cycle analysis.

Rotating detonation combustion

The Rotating Detonation (RD) engine is powered by a novel form of combustion, and has recently been hailed as a promising revolutionary air vehicle and power generation driver. Employing pressure gain combustion, RD engines boast the potential of higher thermo-dynamic efficiency and offer a possible breakthrough for the plateauing conventional pro-pulsion technology. Nonetheless, much remains to be understood about the fundamen-tal principles governing RD waves, before the pursuit of the coveted gains in performance.

The group’s current work primarily focuses on developing a robust model to investigate the underlying wave phenomena through high-fidelity computational fluid dynamics sim-ulations. Leveraging on our expertise in combustion analytics, the aim is to study the mechanisms behind RD and contribute towards improvements of combustor design.

Ramjet and scramjet combustion

Supersonic flight is expected to make a commercial resurgence in the future as new hy-drogen-powered propulsion systems are developed. Ramjet and scramjet engines are promising technologies that could enable intercontinental civil transportation at super-sonic and hypersonic speeds while minimizing greenhouse gas emissions. Operating within the stratosphere, these high-speed aircraft could substantially reduce the shortest travel times between continents, bringing the world closer together.

At our division, we conduct fundamental research into supersonic combustion, focusing on critical areas such as flame stabilization, shock-boundary layer interactions, combus-tion chemistry, plasma-assisted combustion, and nitric oxide formation. This research is essential to making ramjet and scramjet technology viable. Collaborate with leading global partners, we utilize high-fidelity computer simulations to build knowledge in these key areas.

Jet engines and gas turbines

Gas turbine engines are extensively used for aircraft propulsion and power generation. Introducing alternative fuels into the existing infrastructure could reduce their climate im-pact, and we explore the technical consequences of this transition through numerical simulations and experimental campaigns.

Our simulations target a wide range of cases and conditions, including laminar flames, lab-scale representative rigs, and full-scale jet engines. This is done in close collabora-tion with experimentalists, allowing for mutual validation between datasets. Through this research, we enhance the predictive capabilities of our models and open new design paths for the next generation of gas turbines.

Emissions

Gas turbine engines are used extensively in transportation and power generation, and re-ducing their carbon emissions will be crucial for combating climate change. Engines are also capable of emitting a range of harmful pollutants, including carbon monoxide, soot, and nitrogen oxides, which must be minimized to protect people and the local environ-ment. The emission profile is heavily dependent on the chemical composition of the fuel, and dedicated research is required to explore the nature of this relationship as traditional fossil fuels are phased out in favor of new, carbon-neutral fuels.

We use engine tests and numerical simulations to study if, how, and why different fuels lead to different emission profiles. Our work includes direct measurements on real gas turbines, compact chemical kinetics simulations, and high-fidelity CFD of full-scale en-gines. The wealth of data generated through this work gives us the understanding required to develop accurate predictive models for a wide range of fuels.

Plasma-assisted combustion

Plasma-Assisted Combustion (PAC) is a promising technology for improving fuel effi-ciency and reducing emissions. By enhancing reactivity, PAC enables leaner combustion and supports the use of sustainable fuels through better flame stabilization.

Our research focuses on advancing the understanding of PAC using numerical modeling and simulation to complement experimental studies. Previous work has explored the be-havior of microwave-induced plasma through simulations ranging from 0D (zero-dimen-sional) to 3D. However, integrating microwave-induced plasma into real turbines or en-gines presents significant challenges.

To address this, our current research is centered on Gliding Arc Discharge (GAD), an al-ternative method for generating low temperature plasma that is more compatible with turbine and engine environments. We aim to model GAD and investigate its effects on chemical kinetics to better understand its role in combustion systems.