Researchers from Tokyo University of Science and Kyoto University have developed a breakthrough method to suppress dangerous combustion instability in engines using network science. Published in Physical Review Applied, the study applies complex network analysis to identify and disrupt critical regions that drive destructive pressure oscillations in combustors.
Research Overview at a Glance
| Detail | Information |
|---|---|
| Lead Researchers | Prof. Hiroshi Gotoda (Tokyo U of Science), Prof. Ryoichi Kurose (Kyoto U) |
| Journal | Physical Review Applied (Vol. 24, Issue 1) |
| Publication Date | July 1, 2025 |
| Method | Complex network analysis of turbulence |
| Key Discovery | Scale-free network topology in spray combustion |
| Application | Gas turbines, aircraft engines |
The Problem: Combustion Instability
Combustion instability causes dangerous pressure oscillations inside gas turbines and aircraft engines—vibrations so intense they can cause fatal structural damage to combustor walls. The problem occurs when acoustic waves, heat release, and flow patterns interact in a strong feedback loop, amplifying each other until the entire system becomes unstable.
The complex interaction has made it difficult to predict when and where dangerous oscillations will emerge, motivating researchers to seek new analytical frameworks.
The Network Science Solution
The research team developed a “turbulence network” where each point in the flow field represents a node with connections showing vortex interaction strength. Their analysis revealed the network exhibits a scale-free topology—a pattern where a few highly connected hubs dominate the entire system’s behavior.
Key Findings:
Network hubs appear and disappear in sync with the formation and collapse of large-scale organized vortices. When organized vortex structures form, scale-free network topology emerges; when they collapse, the network topology disappears.
The researchers identified “connector communities”—specific regions where different network parts interact most strongly. By strategically placing small physical obstacles in these critical regions, they successfully suppressed combustion instability.
How It Works
The obstacles disrupt vortex interactions that sustain the destructive feedback loop, significantly reducing both acoustic pressure fluctuations and coupling between pressure and heat release oscillations.
This approach provides engineers with a new tool for identifying where to intervene in combustion systems to prevent instability—potentially leading to more stable combustors across various industrial applications.
Broader Impact
“Our work shows that turbulence networks not only characterize the structural organization of turbulent flows but also provide deeper insights into the temporal evolution of dominant flow structures,” explain Professors Gotoda and Kurose. “These findings offer important insights into network-based strategies for suppressing combustion instability.”
The network-based analysis represents a promising fusion of mathematical information science with combustion research, offering a new paradigm for understanding complex fluid dynamics.
Applications:
- Gas turbines for power generation
- Aircraft engines
- Industrial combustors
This could contribute to multiple sustainable development goals through cleaner energy and higher industrial and transportation efficiency.
What’s Next
“In our next study, we will conduct numerical simulations with different geometries and sizes of the obstacle to gain a deeper understanding of the suppression mechanism of spray combustion instability,” the researchers note.
The work extends understanding beyond earlier research on gaseous combustion systems by revealing the dynamic appearance, disappearance, and reappearance of scale-free topologies during spray combustion instability.
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