航空发动机噪声源分析及喷流噪声抑制技术研究

发布时间：2018-12-15 14:51

【摘要】：噪声是现代大型民用客机设计的关键指标之一,民航飞机噪声的主要来源包括机体噪声和发动机噪声,随着现代大涵道比发动机飞机的发展,发动机的噪声水平已经有了明显的降低,但仍然是大型民用飞机的主要噪声源之一。随着世界航空对航空发动机的噪声要求的日益严格,对于大涵道比涡扇发动机的噪声控制变的尤为重要。因此,针对航空涡扇发动机,本文开展了噪声源分析和喷流噪声抑制技术的研究。在噪声源分析方面,分析了发动机不同部位的噪声源(包括叶轮机机噪声、燃烧噪声和喷流噪声),首先对发动机叶轮机噪声进行分析,了解了风扇噪声的产生机理以及产生的噪声类型,分清风扇噪声中的主要次要噪声;其次对发动机燃烧室噪声进行分析,由于航空发动机燃烧室噪声的复杂性,本文主要分析了燃烧室噪声产生的机理以及燃烧室噪声的影响因素;最后对发动机的喷流噪声的机理及特性进行了介绍。在噪声抑制方面,针对上述噪声产生的机理及特性,分析了几种噪声抑制技术,首先,本文在现有文献的参考下,分析了四种叶轮机噪声的抑制技术,对噪声抑制方面均有良好的效果,并且对其中增加转静子距离噪声抑制技术通过Ansys软件进行建摸,通过速度云图和声功率云图得到,增加5mm的转静子距离,噪声可以降低大约4.2dB;其次由于航空发动机燃烧室环境条件苛刻以及国内外学者对燃烧室噪声抑制技术方面研究不多,本文针对发动机燃烧室噪声影响因素进行了分析,采用吸声技术是燃烧室目前最有效的噪声抑制方法;最后,在喷流噪声抑制技术方面,本文选取了锯齿形喷管降噪技术,通过Ansys软件对一个发动机模型进行模拟计算,得出其喷流的温度、速度和噪声分布,并通过图像分析和对比,得出了锯齿型尾喷管大概能够降低喷流噪声4-5dB,证明了锯齿形喷管喷流噪声抑制技术的可行性,在此基础上,本文研究了锯齿形喷管齿数对喷流噪声抑制效果的影响,得出了优化齿轮数的结果。
[Abstract]:Noise is one of the key indexes of modern civil airliner design. The main sources of civil aircraft noise include airframe noise and engine noise. The engine noise level has been obviously reduced, but it is still one of the main noise sources of large civil aircraft. With the increasingly stringent noise requirements of aero-engines in the world, it is particularly important to control the noise of turbofan engines with large ducts. Therefore, the noise source analysis and jet noise suppression technology are studied for the aero-turbofan engine. In the aspect of noise source analysis, the noise sources of different parts of engine (including impeller noise, combustion noise and jet noise) are analyzed. Firstly, the noise of engine impeller is analyzed. The generation mechanism and types of fan noise are understood, and the main secondary noise in fan noise is distinguished. Secondly, the noise of engine combustor is analyzed. Because of the complexity of combustor noise, the mechanism of combustor noise and the influence factors of combustor noise are analyzed in this paper. Finally, the mechanism and characteristics of engine jet noise are introduced. In the aspect of noise suppression, according to the mechanism and characteristics of the above noise, several noise suppression techniques are analyzed. Firstly, four kinds of impeller noise suppression techniques are analyzed under the reference of existing literatures. It has a good effect on noise suppression, and the noise suppression technology of increasing transposon distance is built by Ansys software, and obtained by velocity cloud diagram and acoustic power cloud diagram, which can increase the transposon distance of 5mm. Noise can be reduced by about 4.2 dB; Secondly, due to the harsh environmental conditions of the aero-engine combustion chamber and the lack of research on the noise suppression technology of the combustion chamber, this paper analyzes the influence factors of the engine combustion chamber noise. Sound absorption technology is the most effective noise suppression method for combustion chamber at present. Finally, in the aspect of noise suppression technology of jet flow, this paper selects the noise-reducing technology of sawtooth nozzle, simulates and calculates an engine model by Ansys software, and obtains the temperature, velocity and noise distribution of jet flow. Through image analysis and comparison, it is concluded that the jagged tail nozzle can reduce the noise of jet from 4 to 5 dB, which proves the feasibility of the noise suppression technology of the jagged nozzle. In this paper, the influence of the number of jagged nozzle teeth on the effect of jet noise suppression is studied, and the results of optimizing the gear number are obtained.
【学位授予单位】：中国民航大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V231.92

【相似文献】