Study on the suppression effect of Helmholtz acoustic cavity on the high-frequency combustion instability

This paper addresses the issue of high-frequency combustion instability in liquid rocket engines and investigates the suppression of unstable combustion using Helmholtz acoustic cavities. A gaseous oxygen-methane model rocket engine thrust chamber equipped with six Helmholtz acoustic cavities was designed. Based on this configuration, hot-firing tests were conducted on the model engine thrust chamber to examine the effects of Helmholtz acoustic cavities on reducing combustion instability amplitudes. Additionally, by varying the cavity lengths, the study explored how different cavity dimensions influenced the suppression of combustion instabilities.