Combustion Chamber Image
Combustion chamber during combustion oscillations in a model rocket engine. (Credit: Hiroshi Gotoda)

Combustion engines can develop high-frequency oscillations, leading to structural damage to the engines and unsafe operating conditions. Researchers clarified the feedback processes that give rise to these oscillations in rocket engines.

The researchers found a relationship between fluctuations in the flow velocity of the fuel injector and fluctuations in the heat release rate of the combustor. The product of the pressure and the heat release rate fluctuations in the combustor is an important physical quantity for understanding the origin of combustion oscillations.

The team discovered power sources that would suddenly collapse and reemerge upstream in a periodic fashion, leading to oscillations in combustion. The analysis could lead to a better understanding of the dangerous oscillations that sometimes arise in rocket engines and other combustors.