锯齿形尾缘喷嘴射流增混与降噪机理研究

发布时间：2018-03-12 07:18

本文选题：锯齿形尾缘喷嘴　切入点：射流　出处：《上海交通大学》2013年硕士论文　论文类型：学位论文

【摘要】：喷嘴的射流噪声问题是目前空气动力学和气动声学领域的一个研究热点。锯齿形尾缘结构具有加工简单、降噪能力显著等优点，是已经应用于航空发动机尾喷管上的被动控制降噪技术，具有重大的研究意义。本文借助实验和数值计算的手段，，在低马赫数情况下，针对圆锥形喷嘴和不同参数锯齿形尾缘喷嘴的射流的气动声学特性进行了研究。渗透度和齿数为本文研究的主要参数，为捕捉速度剪切层的变化，分别研究了射流的涡量场、速度场、湍流度场以及湍动能云图分布，并对射流近场噪声声压级分布、远场噪声频谱和指向性的分布进行了分析。探索了锯齿形尾缘结构是如何通过改变流场结构从而影响声音向远场的辐射。以下是本文的主要研究工作：（1）搭建了气动声学测试台架。试验台架是在气动半消声室中搭建的，主要为进气消声风洞。通过调节辅助风机的转速，保证各参数锯齿形尾缘喷嘴的势流核速度一致。渗透度和锯齿数目是分析射流流动的主要参数，可以有针对性地研究锯齿形尾缘结构对射流气动声学特性的影响；（2）利用数值计算手段对锯齿形尾缘喷嘴和圆锥形喷嘴射流场进行了模拟。首先对各种喷嘴划分了结构化网格，然后进行数值模拟计算。对比了计算和实验结果，验证了不同参数锯齿形尾缘喷嘴对射流流场增混的影响；（3）利用热线技术测量了锯齿形尾缘喷嘴和圆锥形喷嘴的射流流场。分析了不同参数喷嘴的射流平均流场，包括轴向速度场、湍流度场等，较好地说明了锯齿渗透度和齿数对于射流流动结构的影响；（4）用麦克风传声器测量了喷嘴射流远场的散点噪声分布，并在喷嘴出口区域进行了近场噪声场的测量。得到远场噪声频谱和指向性分布结果以及近场噪声的声压级云图，分析了渗透度和锯齿数目对于射流近场噪声声压级的影响及其向场声辐射产生的指向性影响。（5）利用实验和数值分析得到的流场结果和实验测得的声场结果，以气动声学理论为基础，详细地分析了锯齿形尾缘喷嘴射流流动和声学之间的关联，为选择具有优秀声学品质的锯齿形尾缘喷嘴提供了有价值的参考。
[Abstract]:The problem of jet noise is the nozzle aerodynamic and a research hotspot in the acoustic field. The serrated trailing edge structure has the advantages of simple processing, noise reduction ability of significant advantages, is the passive control of noise reduction technology has been applied to the aeroengine nozzle, which has great significance.
In this paper, by means of experiment and numerical calculation method in low Maher number, the jet nozzle and the different parameters of Chevron nozzle aerodynamic acoustic characteristics were studied. The main parameters of permeability and the number of teeth is studied in this paper, to capture changes in velocity shear layer, respectively study the vorticity field the jet, the velocity field, turbulence field and turbulent kinetic energy contours, and the jet near field noise sound pressure distribution, the far field noise spectrum and directional distribution were analyzed. To explore the serrated trailing edge structure is how to change the flow structure so as to affect the sound radiation to the far field. The following is the main research the work of this paper:
(1) to build the aeroacoustic test bench. The test bench is built in a semi anechoic chamber in the gas, mainly for the silencer wind tunnel. By adjusting the auxiliary fan speed to ensure the parameters of Chevron nozzle potential flow velocity. The permeability of the nuclear and the number of main parameters of tooth jet flow, can have the effect of pertinent research of chevron structure on jet acoustic characteristics;
(2) the calculation means of Chevron nozzle and conical nozzle jet flow field was simulated by numerical. Firstly, various nozzles divided the structured grid, and then numerical simulation. Comparing the calculated results and experimental results, verify the different parameters of Chevron nozzle mixing enhancement effect on jet flow field;
(3) the jet flow field of Chevron nozzle and conical nozzle is measured using a hotline analysis techniques. Average flow of jet nozzle with different parameters, including axial velocity field and turbulence field, a better explanation of tooth penetration and tooth number for the influence of jet flow structure;
(4) jet noise scattered far field distribution was measured by a microphone, and the near field noise field measurements at the nozzle exit area. The far field noise spectrum and directional distribution results and the near field noise level images, analyzed the infiltration degree and the number of the sawtooth effect of near field jet the noise level and the radiation field produces sound directivity effects.
(5) the flow field results obtained by experimental and numerical analysis and experimental results to the measured sound field, aerodynamic acoustics theory, a detailed analysis of the association between chevron nozzle jet flow and acoustic, Chevron nozzle has excellent acoustic quality selection provides a valuable reference for.

【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：V231.3;TB535

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