Combustion instability control performance of an improved Helmholtz resonator in the presence of bias flow
Combustion instability may appear due to the interference between heat release rate and acoustically-driven flow perturbation in combustors. In the present study, we experimentally studied the effects of incident sound frequency, cavity depth, and sound pressure level on the sound absorption perform...
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| Published in: | Aerospace science and technology 2021-12, Vol.119, p.107153, Article 107153 |
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| Main Authors: | , , , |
| Format: | Article |
| Language: | eng |
| Subjects: | |
| Online Access: | Get full text |
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| Summary: | Combustion instability may appear due to the interference between heat release rate and acoustically-driven flow perturbation in combustors. In the present study, we experimentally studied the effects of incident sound frequency, cavity depth, and sound pressure level on the sound absorption performance of a Helmholtz resonator (HR) with an optimized neck under bias flow. The greater the bias flow rate, the wider the sound absorption frequency band. The insertion of the honeycomb with minor porosity into the neck caused the central sound absorption frequency to shift to the low-frequency regime. The optimal cavity depth of the HR was also shortened, which is beneficial to save space. Moreover, a proper bias flow increased the maximum sound absorption coefficient of the resonator. When the modified HR was installed in the intake section of a swirl spray combustor, the pulsating pressure in the combustion chamber and plenum were reduced by 78% and 56%, respectively. The CH⁎ chemiluminescence intensity was reduced by 96%. Compared with traditional HR, the improved HR suppressed the pressure and heat release pulsation more effectively. Even if the primary air volume flow rate changed from 4.5 m3/h to 9.5 m3/h, the improved HR ensured that the pulsating pressure amplitude was reduced by about 82% on average. |
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| ISSN: | 1270-9638 1626-3219 |