安装角及雷诺数对压气机叶栅气动噪声特性的影响
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摘要
叶型/叶栅的气动参数对压气机气动性能有着很大的影响，研究人员通过实验
和数值模拟方法致力于叶型/叶栅气动性能的研究，并取得了详实的研究成果。随
着社会和经济的发展，人们对周围环境舒适性的要求越来越高，叶轮机械的气动
噪声逐渐成为人们关注热点。因此，叶型/叶栅的流动诱导噪声与气动性能的关系
也成为设计者必须了解的问题。
气流流经叶栅表面时，形成紊流附面层并发生尾涡脱落，产生的压力脉动作
用在叶栅表面，形成偶极子噪声源；当附面层发展到一定程度，或者来流攻角比
较大时，叶栅表面将发生明显的流动分离，引起叶栅表面压力脉动特征改变，从
而影响叶栅流场辐射噪声。本文在叶栅稠度为 1.0 的条件下改变安装角获得了三种
不同的 NACA651210 平面叶栅，然后结合计算流体力学和边界元方法数值模拟叶
栅通道内的湍流场及流场辐射的噪声，研究安装角、自由来流雷诺数和来流攻角
对叶栅通道内非定常流动特征以及叶栅流场辐射噪声的影响。主要工作和结果如
下：
(1) 本文重点研究网格尺度、声源信息采样点长度对流场以及声场计算的影响，
并结合前人的实验数据对整个计算方法的精度及准确度进行了验证。
(2) 在来流雷诺数为 252000、安装角为 30°、来流攻角为-5°~20°时，计算叶栅
通道内的湍流场以及流场诱导噪声，分析涡量、瞬时流线、叶型尾缘点的压力脉
动以及远场声压辐射随攻角的变化规律。计算结果如下：叶型尾缘点的涡脱落频
率随着来流攻角的增大而降低，大的正攻角下，低频脉动占主导成分。攻角为 5°
时，涡脱落频率呈现出明显的离散特征；而负攻角以及大的正攻角下，呈现出宽
频特征。监测点压力脉动幅值随攻角的增大而减小。对于叶栅外场监测点的总声
压级，在 0°攻角下出现最小值，为 6.5dB；攻角为-5°和5°时，总声压级急剧增大；
随着攻角增大到 5°~20°时，总声压增大趋势变缓。总声压级与阻力系数随攻角的
变化趋势并不一致。
(3) 在来流雷诺数为 252000，安装角分别为 45°、60°时，由流场和声场计算信
息可知，叶型尾缘点的涡脱落频率随攻角的变化趋势同安装角为 30°时基本一致，
除负攻角外，涡脱落频率随着攻角的增大而降低。不同安装角下，叶栅外场监测
点总声压级均是在 0°达到最小值，且安装角为 60°时的总声压级较其它安装角增
加了近 6dB；负攻角下，随着安装角的增大，总声压级逐渐增大；攻角为 5°~20°
时，安装角为 60°的总声压级相对于其它安装角反而降低。结合流场信息，我们可
以推测，安装角为 60°时，大的正攻角下，叶栅吸力面的耗散现象变得严重，消耗
一部分能量，从而使声压级降低。
(4) 在安装角为 30°，来流攻角为 0°时，随着雷诺数的增大，叶型尾缘点的压
力脉动幅值增强；外场辐射声压变大；边界层变薄，流动损失降低。
关键词：压气机叶栅 安装角 雷诺数 大涡模拟 边界元方法
ABSTRACT
Aerodynamic parameters of airfoil/cascade have important influence on the
aerodynamic performance of compressor. Comprehensive research data for
aerodynamic characteristics of cascade are got through the experiments and numerical
simulation. As the social and economic development, people have a very high demand
for surrounding environment comfort and gradually pay more attentions to the
aerodynamic noise of turbomachinery. In that case, compressor designers must master
the relationship between noise induced by the flow of blade/cascade and aerodynamic
characteristics.
Turbulence boundary layer and vortex shedding from trailing edge result from air
flows through cascade surface, which cause the pressure fluctuations and form dipole
noise source; when boundary layer increases, either angle of attack is large, the vortex
separation of cascade surface is clear, which change the pressure fluctuation
characteristics and can also affect aerodynamic noise by the turbulence flow of cascade.
In this present paper, three different cascades are got by changing the stagger angle 30°,
45°, 60° with solidity 1.0, then turbulent flow field of cascade channel and aerodynamic
noise induced by flow are simulated by the computational fluid dynamics and boundary
element method, in order to analyze the influence of unsteady flow characteristics and
radiation noise in different stagger angle, free stream Reynolds number and attack of
angle. The main work and conclusions are as follows:
(1) Firstly, this paper focuses on the mesh scale and influence on flow field and
sound field of sample points of sound source; meanwhile, the precision and accuracy of
the calculation method are verified combining with the previous experimental data.
(2) When the Reynolds number is 252000, stagger angle is 30°, attack angle ranges
from -5° to 20°, the turbulence flow and noise induced by flow field of cascade are
calculated. The vortices, transient streamlines, changes of pressure fluctuation of
trailing point and far-field noise radiation varying with attack angle are analyzed. The
results are shown that the frequency of vortex shedding from trailing edge decrease as
attack angle increases. At larger positive attack angle, low frequency fluctuation is
dominant. The frequency of vortex shedding displays obvious discrete characteristics at
attack angle 5° and broadband characteristics at negative and larger positive attack
angles. The amplitudes of pressure fluctuation decrease as attack angle increase. As for
the total sound pressure level of monitor point at far-field, the minimum appears at
angle of attack 0° and the size is 6.5dB, the total sound pressure level increases sharply
at attack angle -5°, 5° and the trend change gently at 5°~20°. The change trend of total
sound pressure level doesn’t coincide with the drag coefficient.
(3) When the Reynolds number is 252000, stagger angle is 45°, 60°, from the
results of flow field and noise field, the frequency of monitor vortex shedding from
trailing has the same change trend with that of stagger angle 30°, the frequency of
vortex shedding from trailing decrease as attack angle increases except for the negative
angle. The minimum total sound pressure levels of monitor point of different stagger
angle appear at attack angle 0°, and the total sound pressure level of stagger angle 60°
increases by 6dB than others; at negative attack angle, the total sound pressure level
increases varying with the stagger angle; however the total sound pressure lever is
smaller than others when stagger is 60°and attack angle is 5°~20°. Combined with the
flow field, we can amuse that at the stagger angle 60° and larger positive attack angle,
dissipative phenomenon on suction surface of cascade become serious and can consume
a part of energy, in that case, the sound pressure level decrease.
(4) When the stagger angle is 30°, attack angle is 0°, and the Reynolds number
increases, the amplitudes of pressure fluctuation of vertex shedding from trailing
become strong, the sound pressure level of far-field become large, the cascades surface
boundary layer thickness becomes thin and the flow loss decrease
Key words: compressor cascade, stagger angle, Reynolds number, LES,
BEM
目录
中文摘要
ABSTRACT
第一章 绪论 ........................................................................................................................ 1
§1.1 研究背景及意义 ............................................................................................. 1
§1.2 国内外研究历史与现状 ................................................................................. 2
§1.2.1 实验研究现状 ...................................................................................... 2
§1.2.2 数值模拟研究现状 ............................................................................. 3
§1.3 本文研究主要内容 ......................................................................................... 6
§1.4 本文的研究思路 ............................................................................................. 6
第二章 平面叶栅流场及声场数值计算方法 .................................................................. 8
§2.1 流动控制方程及大涡模拟 ............................................................................. 8
§2.1.1 流动控制方程 ...................................................................................... 8
§2.1.2 大涡模拟（LES）方法 .....................................................................11
§2.2 计算模型及网格划分 ................................................................................... 15
§2.2.1 平面叶栅的生成................................................................................ 15
§2.2.2 计算模型网格的划分 ....................................................................... 17
§2.2.3 边界条件的设置................................................................................ 18
§2.3 网格无关性的验证 ....................................................................................... 19
§2.4 收敛的标准以及非定常时间步确定 .......................................................... 21
§2.4.1 计算收敛的判定................................................................................ 21
§2.4.2 非定常时间步的确定 ....................................................................... 21
§2.5 声学数值计算方法 ....................................................................................... 23
§2.5.1 边界元方法的简述 ........................................................................... 23
§2.5.2 声学计算步骤 .................................................................................... 24
§2.5.3 不同声源采样长度对声场计算结果的影响 .................................. 26
§2.5.4 不同展向厚度对外场声辐射的影响 .............................................. 28
§2.6 模拟方法可靠性的验证 ............................................................................... 29
§2.7 本章小结 ........................................................................................................ 32
第三章 安装角对叶栅流动及噪声特性的影响............................................................ 33
§3.1 不同安装角叶栅的定常流场分析 .............................................................. 33
§3.2 不同安装角下叶栅非定常流动特性 .......................................................... 35
§3.2.1 不同安装角下叶栅的涡量分布....................................................... 35
§3.2.2 不同安装角下叶栅内瞬时流线分布 .............................................. 39
§3.2.3 不同安装角下叶栅尾缘点的压力脉动 .......................................... 42
§3 .3 不同安装角下叶栅的外场辐射噪声 .......................................................... 47
§3.4 本章小结 ........................................................................................................ 52
第四章 雷诺数对叶栅噪声辐射特性的影响 ................................................................ 53
§4.1 不同雷诺数下叶栅的定常流场分析 .......................................................... 53
§4.2 不同雷诺数下的叶栅的非定常流动特性 .................................................. 55
§4.2.1 不同雷诺数下的尾迹区变化 ........................................................... 55
§4.2.2 不同雷诺数下的边界层厚度的变化 .............................................. 58
§4.2.3 不同雷诺数下的压力脉动的变化 .................................................. 60
§4.3 不同雷诺数下叶栅的外场辐射噪声 .......................................................... 62
§4.4 本章小结 ........................................................................................................ 67
第五章 结论与展望 ......................................................................................................... 68
§5.1 本文主要结论................................................................................................ 68
§5.2 展望 ................................................................................................................ 69
主要符号表 ......................................................................................................................... 70
附录 ...................................................................................................................................... 71
参考文献 ............................................................................................................................. 72
在读期间公开发表论文和承担科研项目及取得成果 .................................................. 75
致谢 ...................................................................................................................................... 76
摘要：
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摘要叶型/叶栅的气动参数对压气机气动性能有着很大的影响，研究人员通过实验和数值模拟方法致力于叶型/叶栅气动性能的研究，并取得了详实的研究成果。随着社会和经济的发展，人们对周围环境舒适性的要求越来越高，叶轮机械的气动噪声逐渐成为人们关注热点。因此，叶型/叶栅的流动诱导噪声与气动性能的关系也成为设计者必须了解的问题。气流流经叶栅表面时，形成紊流附面层并发生尾涡脱落，产生的压力脉动作用在叶栅表面，形成偶极子噪声源；当附面层发展到一定程度，或者来流攻角比较大时，叶栅表面将发生明显的流动分离，引起叶栅表面压力脉动特征改变，从而影响叶栅流场辐射噪声。本文在叶栅稠度为1.0的条件下改变安装角获得了三种不同的...
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作者：侯斌
分类：高等教育资料
价格：15积分
属性：80 页
大小：3.88MB
格式：PDF
时间：2024-11-19
