| 摘要: |
| 采用数值模拟方法研究了三股流喷管的流动与噪声机理，增加倾斜结构对流动与噪声特性的影响。结果表明：在设计工况，第三股流的引入虽避免了高速风扇流与自由来流的直接接触，降低了喷流与自由来流间的掺混强度，但受轴对称式结构限制，小涵道比的第三股流沿周向均匀分布，其在各方向上的降噪效果有限，对喷管总声压级分布的影响较小。增加第三股流通道倾斜结构，其涵道比增加，喷管下侧主流核心区末端与自由来流间掺混强度降低，30°观测角下的总声压级较轴对称式的下降约2.6dB。考虑第三股流的涵道比匹配，对倾斜结构进行控制涵道比与出口气流角度的型面设计，喷管下侧主流核心区末端与自由来流间掺混强度的降低幅度低于不控制涵道比倾斜结构，30°观测角下的总声压级较轴对称式的下降约1.5dB。 |
| 关键词: 喷管 机理分析 流动特性 噪声特性 降噪结构 涵道比控制 |
| DOI：10.13675/j.cnki.tjjs.2302043 |
| 分类号:V231 |
| 基金项目:国家自然科学基金（52076180）；陕西省杰出青年科学基金（2021JC-10）；国家科技重大专项（J2019-Ⅱ-0015-0036）；航空发动机及燃气轮机基础科学中心项目（P2022-B-I-002-001；P2022-B-Ⅱ-010-001）；中央高校基本科研业务费专项资金。 |
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| Influence Mechanism of Asymmetric Structure on Flow and Sound Field of Three-Stream Nozzle |
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YANG Yu-ming1, ZHOU Li1,2, SHI Jing-wei1, WANG Zhan-xue1
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1.School of Power and Energy,Northwestern Polytechnical University,Xi’an 710072,China;2.Collaborative Innovation Center for Advanced Aero-Engine,Beijing 100190,China
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| Abstract: |
| The flow and noise mechanism of the three-stream nozzle and the influence of the asymmetric structure on the flow and noise characteristics were studied by numerical simulation. The results show that although the tertiary stream avoids the direct contact between the high-speed fan flow and the free stream， and reduces the mixing intensity between the jet and the free stream， the tertiary stream with small bypass ratio is uniformly distributed along the circumference due to the restriction of the axisymmetric structure， its noise reduction effect is limited in all directions， and its impact is small on the distribution of the nozzle overall sound pressure level. When the asymmetric structure of the tertiary stream is added， the bypass ratio increases， the mixing intensity between the end of the primary potential core and the free stream decreases， and the overall sound pressure level at 30°observation angle decreases by about 2.6dB compared with the axisymmetric structure. Considering the bypass ratio matching of the tertiary stream， the asymmetric structure is profiled designed to control the bypass ratio and the outlet flow angle. The reduction magnitude of the mixing intensity between the end of the primary potential core and the free stream at the lower side of the nozzle is lower than that of the asymmetric structure without controlling the bypass ratio. The overall sound pressure level at 30°observation angle decreases by about 1.5dB compared with the axisymmetric structure. |
| Key words: Nozzle Mechanism analysis Flow characteristics Noise characteristics Noise reduction structure Bypass ratio control |
