Slightly increasing the initial temperature and pressure in a large gas-turbine engine would more than double the engine’s efficiency, an international research team that includes Nebraska’s Jae Sung Park has concluded.
“Small changes of the initial temperature and the pressure lead to huge changes later in the performance of the engine,” said Park, Richard L. McNeel Associate Professor of mechanical and materials engineering. “If we can find the optimum combination of the temperature and pressure, those engines, like the ones in ships and airplanes, will be able to run longer and use less fuel.”
The results of the research – “Effects of initial and operating conditions on the supercritical carbon dioxide Brayton cycle” - were chosen as an Editor’s Pick in the March 2025 edition of the prestigious journal Physics of Fluids. The paper was co-authored by Park, Richard L. McNeel Associate Professor of mechanical and materials engineering, Senthil Kumar Raman, associate professor and head of aeronautical engineering at India’s Kalasalingam Academy of Research and Education, and Simon Song, professor of mechanical engineering at South Korea’s Hanyang University.
Typically, large gas-turbine engines operate on Brayton cycles – a thermodynamic process characterized by isentropic compression and expansion and isobaric heat addition and rejection. In this process, air is compressed inside the engine, adding heat (usually through combustion), expanding the heat through a turbine and then rejecting the heat.
The researchers found that the supercritical carbon dioxide (s-CO2) power cycle is a potential candidate for increasing thermal energy conversion efficiency because of its real gas properties.
In this process, Park said, increasing the initial pressure and temperature slightly above the supercritical state of carbon dioxide (73.77 bar and 304.13 K) and introducing heat regeneration after combustion can increase the engine’s efficiency by almost 105 percent.
“Bigger systems, like those in airplanes and ships and submarines are probably the top targets for application of this process,” Park said. “Hopefully, it could be manufactured in the near future.”
Much of the work that has been done to this point has been computational simulations and theoretics, but Park said the team is looking forward to the physical experimentation phase of the research.
“Prof. Song is the experimental expert on our team, and I think he will be looking to conduct testing on real engines soon,” Park said. “But that’s hard to do because it’s hard to find engines that big to test and there aren’t a lot of facilities in which to test them.”
