Research Article
Investigation on Acoustic Properties of Thruster Chamber with Coaxial Injectors and Plenum Chamber
Table 5
Eigenfrequency, power amplitude, and damping rate of acoustic modes in the Model C chamber.
| | Length of the injector (cm) | | 0 | 2.2 | 3.2 | 4.4 | 6.2 | 7.8 | 10 |
| | Resonator’s tuning frequency (Hz) | — | 3750 | 2578 | 1875 | 1330 | 1057 | 825 | | 1L acoustic mode | Eigenfrequency (Hz) | 985 | — | — | — | — | — | — | | Amplitude (kPa) | 0.76 | — | — | — | — | — | — | | Damping factor | 11.8% | — | — | — | — | — | — | | 2T acoustic mode | Eigenfrequency (Hz) | 3771 | 3886 | 3813 | 3756 | 3777 | 3771 | 3648 | | Amplitude (kPa) | 1.17 | 0.55 | 1.13 | 0.78 | 0.24 | 0.41 | 1.0 | | Damping factor | 3.4% | 4.4% | 2.2% | 4.2% | — | 3.8% | 3.6% | | 1L2T acoustic mode | Eigenfrequency (Hz) | 3961 | 4076 | 4092 | 4147 | 4060 | 4062 | 4160 | | Amplitude (kPa) | 0.58 | 0.65 | 0.97 | 0.42 | 0.52 | 0.66 | 0.47 | | Damping factor | 8.2% | 2.5% | 4.3% | 4.0% | 6.6% | 2.5% | 3.5% | | 2L2T acoustic mode | Eigenfrequency (Hz) | 4461 | 4644 | 4558 | — | 4627 | — | 4583 | | Amplitude (kPa) | 0.31 | 0.78 | 0.74 | — | 0.58 | — | 0.68 | | Damping factor | 3.2% | 2.0% | 2.5% | — | 3.3% | — | 2.1% | | Unidentified frequency peaks | Eigenfrequency (Hz) | — | — | — | — | 3494 | — | — | | Amplitude (kPa) | — | — | — | — | 0.85 | — | — | | Damping factor | — | — | — | — | 2.5% | — | — |
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