基于多物理场分析的喷嘴结构设计
发布时间：2021-01-20 00:49
喷嘴通常是不同横截面面积的管道,其结构形式对射流动力学性能有很大影响。喷嘴通常用于控制从其流出的排出流体的流动速度、方向、形状和压力。当流体流过喷嘴时管内的高压气流在工作条件下产生一定程度的噪声。工业上使用的流体输运设备如用于处理不锈钢的高压喷嘴,会产生120 dB或以上的强噪声,严重污染车间的工作环境,对工人的健康和工作效率产生负面影响。因此,论文通过对气流噪声的机理和特性进行研究,设计满足热量传递的条件下较低噪声水平的喷嘴结构。试验研究喷嘴构型对高压水射流流动影响时结果最为可靠,然而成本昂贵且周期较长,因此本文应用涡粘性模型和二阶精度的有限体积法对不同喷嘴的外部流场进行了大涡模拟,研究了不同喷嘴外部流场非定常结构特性,具体内容如下:首先,根据压力、速率和噪声之间的关系设计喷嘴的结构;其次,通过分析高压射流引起的噪声构建射流模型;第三,通过数值模拟的方法对不同喷嘴结构和射流噪声的关联进行了研究,计算采用直径为0.8 mm的喷嘴,分别以不同的形式排列。采用CATIAV5软件设计了喷嘴形状,并利用ANSYS和FLUENT对气流分析进行了验证,采用计算空气声学解算器对喷嘴产生的流场进行激励...
【文章来源】：天津大学天津市 211工程院校 985工程院校 教育部直属院校
【文章页数】：112 页
【学位级别】：硕士
【文章目录】：
摘要
Abstract
Nomenclature
Abbreviations
Chapter 1 Introduction
1.1 The purpose and significance of the research
1.2 Development and research status of aero acoustics
1.3 Research background and present situation of jet noise
1.4 Outline of the Thesis
1.5 A presentation on Fluid Flow
1.5.1 Definition
1.5.2 Types of Fluid Flow
1.5.3 Flow Equations
1.5.4 Area ratio
Chapter 2 Types and Characteristics of Nozzle
2.1 Definition
2.2 Types of nozzles
2.3 Nozzle flows
2.4 Introductions to Aeroacoustics
2.5 Turbulence in nozzle
2.5.1 Turbulent Flow Structures
2.5.2 Turbulence Models Available in FLUENT
2.5.3 The k–εTurbulence Models
2.5.4 Large Eddy Simulation（LES）
2.5.5 Boundary Layer Separation
2.5.6 Boundary Layer and Nozzle Flow Separation
Chapter 3 Modeling Descriptions
3.1 Governing Equations of Fluid Flow
3.1.1 Mass is conserved（Law of Mass Conservation）
3.1.2 Momentum is conserved（Newton's Second Law）
3.1.3 Energy is conserved（First Law of Thermodynamics）
3.2 Turbulence Modeling
3.2.1Closure problem
3.2.2 Calculating Turbulent Viscosity
3.2.3 Eddy viscosity
3.3 Near wall treatment and Y+value
Chapter 4 Fundamental of spray noise
4.1 Wave equation
4.2 Mechanism of spray noise
4.3 Characteristics of spray noise
Chapter 5 Flow field analysis of spray noise
5.1 Introduction
5.2 3D Geometric modeling and parameters
5.3 Theoretical mechanism of acoustic radiation in flow field
5.3.1 Turbulence theory
5.3.2 Motion equation and quasi similarity condition
5.3.3 Turbulence mechanism
5.3.4 Acoustic analogies
5.3.5 Lighthill's Acoustic Analogy
5.3.6 Ffowcs Williams& Hawking's extended analogy using permeablecontrol surface
5.4 Turbulence model of jet flow field
5.4.1 modeling of jet flow field
5.4.2 Mesh generation
5.4.3 Broadband Noise Models
5.4.4 Broadband noise prediction based on LES
5.5 The Interaction between a Background Flow and an Acoustics Field
5.6 Environmental noise control
5.6.1 Introduction
5.6.2 Sound pressure and Sound power– Effect and Cause
5.6.3 Relationship between Sound Pressure and Sound Power Levels
5.7 converting sound power level to sound pressure level
5.8 Results
Chapter 6 Summary and Prospect
6.1 A summary of the full text
6.2 Work prospect
Bibliography
Publication of papers and participation in scientific research
Acknowledgement
本文编号：2988024
【文章来源】：天津大学天津市 211工程院校 985工程院校 教育部直属院校
【文章页数】：112 页
【学位级别】：硕士
【文章目录】：
摘要
Abstract
Nomenclature
Abbreviations
Chapter 1 Introduction
1.1 The purpose and significance of the research
1.2 Development and research status of aero acoustics
1.3 Research background and present situation of jet noise
1.4 Outline of the Thesis
1.5 A presentation on Fluid Flow
1.5.1 Definition
1.5.2 Types of Fluid Flow
1.5.3 Flow Equations
1.5.4 Area ratio
Chapter 2 Types and Characteristics of Nozzle
2.1 Definition
2.2 Types of nozzles
2.3 Nozzle flows
2.4 Introductions to Aeroacoustics
2.5 Turbulence in nozzle
2.5.1 Turbulent Flow Structures
2.5.2 Turbulence Models Available in FLUENT
2.5.3 The k–εTurbulence Models
2.5.4 Large Eddy Simulation（LES）
2.5.5 Boundary Layer Separation
2.5.6 Boundary Layer and Nozzle Flow Separation
Chapter 3 Modeling Descriptions
3.1 Governing Equations of Fluid Flow
3.1.1 Mass is conserved（Law of Mass Conservation）
3.1.2 Momentum is conserved（Newton's Second Law）
3.1.3 Energy is conserved（First Law of Thermodynamics）
3.2 Turbulence Modeling
3.2.1Closure problem
3.2.2 Calculating Turbulent Viscosity
3.2.3 Eddy viscosity
3.3 Near wall treatment and Y+value
Chapter 4 Fundamental of spray noise
4.1 Wave equation
4.2 Mechanism of spray noise
4.3 Characteristics of spray noise
Chapter 5 Flow field analysis of spray noise
5.1 Introduction
5.2 3D Geometric modeling and parameters
5.3 Theoretical mechanism of acoustic radiation in flow field
5.3.1 Turbulence theory
5.3.2 Motion equation and quasi similarity condition
5.3.3 Turbulence mechanism
5.3.4 Acoustic analogies
5.3.5 Lighthill's Acoustic Analogy
5.3.6 Ffowcs Williams& Hawking's extended analogy using permeablecontrol surface
5.4 Turbulence model of jet flow field
5.4.1 modeling of jet flow field
5.4.2 Mesh generation
5.4.3 Broadband Noise Models
5.4.4 Broadband noise prediction based on LES
5.5 The Interaction between a Background Flow and an Acoustics Field
5.6 Environmental noise control
5.6.1 Introduction
5.6.2 Sound pressure and Sound power– Effect and Cause
5.6.3 Relationship between Sound Pressure and Sound Power Levels
5.7 converting sound power level to sound pressure level
5.8 Results
Chapter 6 Summary and Prospect
6.1 A summary of the full text
6.2 Work prospect
Bibliography
Publication of papers and participation in scientific research
Acknowledgement
本文编号：2988024
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