Discovering the Cause of a Deadly Problem in Rocket Engine Combustors - SciTechDaily

Via advanced analyses, scientists shed light on the mechanism of a fatal problem plaguing combustion chambers in rocket engines?

Rocket engines contain confined combustion systems, which are, essentially, combustion chambers.

In these chambers, nonlinear interactions among turbulent fuel and oxidizer flows, sound waves, and heat produced from chemical reactions, cause an unstable phenomenon called ‘combustion oscillations.’ The force of these oscillations on the body of the combustion chamber — the mechanical stress on the chamber — is high enough to threaten catastrophic failure of the engine.

Gotoda says, “Our main purpose was to reveal the physical mechanism behind the formation and sustenance of high-frequency combustion oscillations in a cylindrical combustor using sophisticated analytical methods inspired by symbolic dynamics and complex networks.” These findings have also been covered by the American Society of Physics in their news section, and by the Institute of Physics on their news platform Physics World.

The combustor the scientists picked to simulate is one of model rocket engines.

They were able to pinpoint the moment of transition from the stable combustion state to combustion oscillations and visualize it.

These findings provide reasonable answers for why combustion oscillations occur, albeit specific to liquid rocket engines.

Gotoda explains, “Combustion oscillations can cause fatal damage to combustors in rocket engines, aero engines, and gas turbines for power generation.

Therefore, understanding the formation mechanism of combustion oscillations is an important research subject.

Our results will greatly contribute to our understanding of the mechanism of combustion oscillations generated in liquid rocket engines.”.

Indeed, these findings are significant and can be expected to open doors to novel routes of exploration to prevent combustion oscillations in critical engines.

Reference: “Formation mechanism of high-frequency combustion oscillations in a model rocket engine combustor” by Satomi Shima, Kosuke Nakamura, Hiroshi Gotoda, Yuya Ohmichi and Shingo Matsuyama, 22 June 2021, Physics of Fluids.

August 1, 2021