供热循环泵系统振动噪声分析及其控制技术研究

发布时间：2018-02-04 05:35

本文关键词： 声振耦合隔振降噪自由阻尼约束阻尼低频振动　出处：《沈阳工业大学》2014年博士论文　论文类型：学位论文

【摘要】：随着人们生活的发展，水泵系统已经成为人们生活中所必不可少的一部分。水泵系统运转时产生的振动和噪音已经成为人们生活中一种新的污染。尤其是随着建筑结构趋向于简洁化、轻薄化，将系统产生的振动及噪音去除至达到人们的要求显得越来越困难。本文引入并推导了声振耦合理论，针对实践中难以解决的低频振动与低频噪声问题进行分析，将声振耦合理论应用于供热循环泵系统实际工况中，定性并定量地分析了振动与声场之间的相互影响。本文将声振耦合效应分两方向进行讨论，即声场环境对系统振动特性的影响以及系统振动对声场分布情况的影响。此外，鉴于水泵管道系统振动信号的复杂性，为了更准确地从复杂复合信号中提取出水泵管道系统振动信号，提出了基于噪声辅助集合的门限自回归模型延拓经验模式分解算法(E-TAR-EMD)分析提取振动特征，以便于进一步的声振耦合分析。首先，应用声振耦合有限元理论推导并计算声场对振动模态的影响，使用有限元软件Patran结合Virtual lab分析软件仿真计算噪声声场环境对水泵常见管路的振动模态的影响情况，并搭建模仿实际工况下的供热循环泵系统的实验台，以该实验台运转情况为例进行实验验证。理论分析与实验验证结果表明，噪声声场会对处于其中的管路的振动模态有较大影响，引起振动峰值频率的偏移。在不同频率下，由声场附加载荷引起管路的附加位移相差很多。声振强耦合频率段主要集中在300Hz中频段，这一点实际测量与理论推导基本相符，对改进隔振措施有指导意义。之后，本文以实际工程为背景，采用声振耦合边界元理论分析楼板振动对通过楼板后的声场的影响。针对实际工程中难以解决的噪声通过楼板后在某些频段存在非正常峰值的问题进行了分析与讨论，并指出此问题原因在于室内声场与机组运行将振动传递给楼板，而楼板振动的同时辐射声波与透过楼板的声波产生叠加，从而影响了楼板的投射声场分布。为准确获取楼板振动信号用于进一步分析，本文应用基于噪声辅助集合的门限自回归模型延拓经验模式分解算法(E-TAR-EMD)对采集到的复杂复合信号进行提取，从而获得了较准确的楼板振动特性。在此基础上，分别计算楼板透射声波与楼板振动辐射声波的传递规律与声场分布情况，并将两种声波传递规律进行叠加，，对声场分布情况进行耦合计算，得到不同频段下测点附近的声压级云图。将运算结果与实际测量结果对比，符合程度良好，从而证明了楼板振动对测点附近声场的影响，解释了某些频段声音难以消除的原因。最后，针对实际工程中普遍存在的管道低频振动噪声问题，建立了数学模型，分析了传统弹簧隔振措施不能够完善解决管道低频振动噪声问题的原因，提出采用阻尼措施来吸收振动能量，实现减振与降噪的方案。提出自由阻尼与约束阻尼两种阻尼措施，在微观角度分别推导了两种阻尼措施的耗能机理与隔振效果，对两种不同机理的阻尼措施进行了参数化分析。在理论分析的基础上，以阻尼变形量为目标函数进行了参数优化实验验证。理论分析与实验验证结果表明，在同等条件下，约束阻尼措施的总体隔振效果要优于自由阻尼措施，不同材料参数对隔振效果有较大影响，对今后的阻尼措施及其优化具有重要的参考价值，对水泵系统振动噪声治理手段的发展具有重大意义。
[Abstract]:With the development of people's life, the water pump system has become a part of the indispensable to people's life. The noise and vibration caused by the operation of the water pump system has become a new pollution in people's lives. Especially with the building structure tend to be simple, lightweight, vibration and noise will be generated to reach people removal system the requirement is more and more difficult. This paper introduces and deduces the acoustic coupling theory, according to the analysis of low frequency vibration and noise problems are difficult to solve in practice, the acoustic coupling theory is applied to the actual working condition of heating circulating pump system, the relationship between vibration and sound field of the qualitative and quantitative analysis. This paper will sound vibration in two direction are discussed, the sound environmental impact on the vibration characteristics of the system and the influence of system vibration on the sound field distribution. In addition, in view of the pump pipe The complexity of vibration signal of the system, in order to accurately extract the signal from the complex vibration signals of pump pipeline system, put forward the noise assisted set threshold auto regression model based on extension of empirical mode decomposition (E-TAR-EMD) algorithm to extract the features of vibration analysis, in order to facilitate the acoustic coupling of further analysis.
First of all, influence of the application of acoustic coupling finite element theory and field calculation of vibration mode, influence the use of finite element software Patran combining with Virtual lab analysis and calculation of noise environment on the pump vibration mode of common pipeline simulation software, and set up the experimental platform to imitate the heating circulating pump system of actual working conditions, in the experiment Taiwan operation experiments were carried out as an example. Theoretical analysis and experimental results show that the noise will have great influence on the vibration mode in the pipeline, caused by vibration of the peak frequency offset. Under different frequencies, the additional displacement of the pipeline caused by sound additional loads a lot of difference. The acoustic vibration frequency is mainly concentrated in strong coupling in the 300Hz band, a practical measurement is consistent with the basic theory, guiding significance to the improvement of isolation measures.
After that, this paper takes the actual project as the background, using the coupled boundary element theory of sound and vibration analysis of influence of floor vibration through the floor after the noise in the sound field. It is difficult to solve in practical engineering through the floor after the non normal peak problem in certain frequency band are analyzed and discussed, and pointed out that the cause of this issue lies in the operating room sound field with the unit to transmit the vibration to the floor, and the floor vibration and radiation of acoustic waves and sound waves through the floor of the stack, thus affecting the projection field distribution. In order to obtain the floor slab vibration signal for further analysis, the application of noise assisted set threshold auto regression model based on extension of empirical mode decomposition algorithm (E-TAR-EMD) complex of the collected signals were extracted to obtain the floor vibration characteristics accurately. On this basis, calculate the acoustic transmission and the floor Transfer law and sound field distribution of acoustic radiation floor vibration, and two kinds of acoustic transmission rules were superimposed, coupling calculation on acoustic field distribution, obtained under different frequency bands measured sound pressure level near the point cloud. The operation results and actual measurement results, good agreement, which proves the influence of floor vibration measuring points near field, explains why some band sound difficult to eliminate.
Finally, aiming at the pipeline exists in practical engineering of low frequency vibration noise problem, a mathematical model is established, the analysis of the traditional spring vibration isolation measures can not improve the reason and solve the problems of vibration and noise of pipeline frequency, the damping measures to absorb vibration energy, reduce vibration and noise reduction scheme. Put forward two kinds of free damping and constrained damping the damping measures in microcosmic angle are deduced the energy dissipation mechanism of two kinds of damping measures and the effect of vibration isolation, damping mechanism of two different measures of parametric analysis. On the basis of theoretical analysis, the deformation of the damping parameter optimization experiment for the objective function. The theoretical analysis and experimental results show that the and under the same conditions, the overall measure of constrained damping vibration isolation effect is better than that of free damping measures, different material parameters have great influence on the effect of vibration isolation, damping for the future The measures and its optimization have important reference value, and it is of great significance to the development of the vibration and noise control methods of the pump system.

【学位授予单位】：沈阳工业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TH38

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