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毕业论文网 > 毕业论文 > 海洋工程类 > 船舶与海洋工程 > 正文

邮轮烟囱排气系统噪声预报与控制毕业论文

 2021-10-24 03:10  

摘 要

大型邮轮在海上正常运行工作时,船体结构会发生总体振动和局部振动,激励源不仅数量繁多并且成因复杂,其激励船体振动,并向周围环境例如空气中和水中不断辐射噪声。在邮轮的正常航行过程中,烟囱产生的噪音主要来自两个方面,其一是烟囱内部流动的流体振动直接产生噪声;其二是烟囱工作时,内部排放流体激励烟囱结构,产生振动并向周围环境中辐射噪声。邮轮烟囱结构产生的振动噪声会严重影响到周边环境,尤其是烟囱出气口周围的甲板公共区域人们的舒适性。由此可见,通过对邮轮烟囱的噪声源进行分析,并数值模拟烟囱噪声是十分有必要的。在邮轮的设计过程中针对其烟囱声学舒适性来进行设计,可避免在邮轮整体建造完成后由于疏忽烟囱噪声控制而导致噪声超标,无法通过相关审核进而造成经济和人力等多方面的巨大损失。

本文以邮轮烟囱的空气辐射噪声为研究对象,针对其典型结构特征,将采取简化其模型为柱壳体结构,然后研究该结构的振动噪声特性的研究方案。研究方法方面,本文选取数值模拟计算,系统地来对简化后的典型邮轮烟囱结构进行振动声辐射特性等方面的分析。通过搜集整理国内外相关行业研究的试验数据,选取与本文研究目标模型相近的部分,将两者结果对比,通过分析误差,来判断本文所选取的研究方法的可靠性是十分之高的。

通过资料搜集,了解工业用烟囱和船舶用烟囱的大概典型结构特征后,对邮轮烟囱模型进行简化,将实际烟囱模型简化为截面为椭圆并且内部均匀分布环肋骨的柱壳体。针对振动特性的分析中,建立模型是第一步;然后导入到有限元软件中,建立典型柱壳体结构的数值模型,确定该模型结构在内部激励下的振动特性及边界振动情况。在针对噪声特性的分析中,利用边界元软件建立典型结构的声学模型,将中计算得到的结果导入建立边界元数值模型并设置为边界条件,针对其内部振动激励源的声学特性进行数值分析计算,以此来完成对邮轮烟囱典型柱壳体结构的振动噪声特性分析。

此外,本文通过控制变量法,对邮轮烟囱的典型柱壳体进行多个特征的变量研究,对比分析计算数据,总结该特征对于烟囱典型模型振动噪声特性的影响,此结论对之后邮轮烟囱结构的设计和振动噪声的控制能够提供十分准确和专业的指导,对提高邮轮的舒适性和提升经济效益也具有重要的意义。

关键词:大型邮轮;烟囱;振动噪声;有限元;边界元

Abstract

When the large-scale cruise ship is operating normally at sea, the hull structure will generate overall vibration and local vibration. The number of excitation sources is not only large and the causes are complex. They stimulate the hull vibration and radiate noise to the surrounding environment, such as air and water. In the normal navigation process of the cruise ship, the noise generated by the chimney mainly comes from two aspects: one is the fluid vibration flowing in the chimney directly generates noise; the other is that when the chimney works, the internal discharge fluid stimulates the chimney structure, generates vibration and radiates noise to the surrounding environment. The vibration and noise produced by the ship chimney structure will seriously affect the surrounding environment, especially the comfort of people in the deck public area around the chimney outlet. It shows that analyzing the noise source of the cruise ship chimney and simulating the noise of the chimney is necessary. In the design process of the cruise ship, the acoustic comfort of its chimneys is designed to avoid the excessive noise caused by the negligence of the noise control of the chimneys after the completion of the overall construction of the cruise ship, and the failure to pass the relevant audit, resulting in huge economic and human losses.

In this paper, taking the air radiation noise of the cruise ship chimney as the research object, aiming at its typical structural characteristics, the simplified model will be adopted as the cylindrical shell structure, and then the research scheme of the vibration and noise characteristics of the structure will be studied. In terms of research methods, this paper selects numerical simulation to systematically analyze the vibration and sound radiation characteristics of the simplified typical ship chimney structure. By gathering and organizing the experimental data of domestic and foreign related industry research, selecting the part that is similar to the research target model of this article, comparing the results of the two, analyzing the errors, and judging the reliability of the research method selected in this paper by calculating the comparison error, it is very high.

Based on the data collection and the understanding of the typical structural characteristics of industrial and marine chimneys, the cruise ship chimney model is simplified, and the actual chimney model is simplified as a cylindrical shell with elliptical section and evenly distributed ring ribs inside. In the analysis of the vibration characteristics, model building is the first step, and then it is imported into the software to build the model of the typical cylindrical shell structure to determine the vibration characteristics and boundary vibration of the model structure under the internal excitation. In noise part, the acoustic model of typical structure is built by using the boundary element software, and the results from the calculation are imported into the boundary element numerical model and set as the boundary conditions. The analysis are accomplished for the acoustic characteristics of the internal vibration excitation source, so as to complete the vibration and noise characteristics analysis of the typical cylinder shell structure of the cruise chimney.

In addition, through the control variable method, this paper studies several characteristics of the typical cylinder shell of the cruise ship chimney, compares and analyzes the calculation data, summarizes the influence of the characteristics on the vibration and noise characteristics of the typical model of the chimney, and from this conclusion very accurate and professional guidance can be put forward for the design of the structure of the cruise ship chimney and the control of the vibration and noise, and can improve the comfort and promotion of the cruise ship Economic benefits are also of great significance.

Key words:Cruise ship;Chimney;Vibration and noise;Finite element;Boundary element

目 录

摘 要 I

Abstract I

第1章 绪论 1

1.1 引言 1

1.2 研究背景及其意义 1

1.3 国内外研究进展 3

1.3.1 类烟囱的振动与声辐射特性 3

1.3.2 壳体结构的振动与声辐射特性 4

1.4 本文的主要研究内容 7

第2章 壳体结构的振动与声辐射理论 8

2.1 引言 8

2.2 研究方法 8

2.3 结构的振动与声辐射理论 9

2.3.1 结构的振动与声耦合 9

2.3.2 壳体结构的振动与声辐射 11

2.4 本章小结 12

第3章 声振数值计算的可靠性 14

3.1 引言 14

3.2 参考文献详细资料 14

3.2.1 文献模型参数 14

3.2.2 文献试验结果 15

3.3 验证数值计算 15

3.3.1 建立数值模型 15

3.3.2 提取计算结果 17

3.3.3 验证数值计算 19

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