In order to determine whether acoustic characteristics obtained in cold case in engineering can represent those in actual cases

acoustic modes and their damping characteristics of thrust chamber were investigated under three conditions: cold case without flow

hot case with flow and turbulent two-phase reactive case. High-amplitude pressure oscillations featured with multi-mode acoustic characteristics were excited by imposing numerical constant-volume bomb into a limited region at the steady flow in a thrust chamber. The damping rate of pressure oscillation of each acoustic mode was evaluated by decay time and half-power bandwidth

thereby damping capacity of each acoustic mode was obtained. Results showed more acoustic modes were excited in cold case than those in two hot cases. The decay times in cold case were longer than those in two hot cases. Moreover

pressure oscillation of each mode in cold case decayed slower than that of the corresponding mode in two hot cases. For the cold case

the amplitude of the first tangential mode was the greatest for the most inspirable acoustic mode. The half-power bandwidth of the first longitudinal mode was the smallest for the most difficult mode to be attenuated. For the two hot cases

the first longitudinal mode was the most inspirable acoustic mode with greatest amplitude and the most difficult mode to be attenuated with smallest half-power bandwidth. Judging from main acoustic modes excited by numerical constant-volume bomb as well as relative damping characteristics

investigation on acoustic performance of thrust chamber in the cold case was reasonable to reveal the acoustic performance under the real condition.