大空间机房的声场分析和降噪方案优化

发布时间：2019-01-05 04:58

【摘要】：厂房或机房内设备工作时产生的噪声很大，当人们长时间工作在高分贝噪声环境下时，会产生精神紧张、注意力分散等问题，影响人们身心健康和正常的工作效率，设备工作的同时也会将振动传递到楼板及围护，令其受迫振动产生二次噪音，，楼板等围护结构产生的振声耦合对建筑安全存在影响。目前，大空间声场计算精度较低，导致噪声治理方案难以优化，治理效果不够理想。本课题通过收集噪声信号，运用盲源分离算法有效精确地分离大空间内主要设备的噪声信号，根据噪声信号频谱特性优化降噪方案，并计入围护结构和主要机械设备的振声耦合，达到更好的减振降噪目的。首先比较不同的盲源分离算法，考虑不同算法的优点以及噪声信号特性，选取计算量小、复杂程度低，且能有效抵抗干扰的盲源分离算法，通过仿真实验结果确定基于高阶统计量的盲源分离算法分离精度更高。为了更好地评价盲源分离精度，本文选取适合空间内噪声信号特性的串音误差方法，由于串音误差方法对于某些特殊的全局矩阵不能做出精确评价，因此优化了传统的串音误差方法，引入全局矩阵中各元素的方差和相关系数，提高了串音误差方法对于特殊矩阵的评价准确度，从而能排除空间内强干扰信号的影响，使噪声场计算精度更高。在此基础上，在实验室中采集真实的混合噪声信号，分离出不同的噪声信号，运用优化的串音误差方法评价分离结果，证明盲源分离算法的分离效果。最后，采集某大型超市地下水源热泵机房的真实混合噪声，分离不同设备产生的噪声信号，针对提取的声信号特性，分别采用了组合式吸声体和管道减振的方法对其进行减振降噪综合治理。优化了影响吸声体吸声系数的穿孔板孔径、穿孔率和厚度结构参数。同时，分离信号中含有热泵机组对楼板振动产生的二次噪音成份，建立机房振声耦合模型，计入振声耦合对声场的影响根据数值模拟计算结果，认为二级减振器中间质量块对减振效果影响最大，优化了减振器中间质量块参数为200kg。经测试可知，优化参数后的减振器对楼板的振动影响明显减弱，热泵机房噪声值降低了14.6dB，振动幅值从4mm/s降低为0.7mm/s，取得了良好的减振降噪效果，课题的研究提高了多设备空间内噪声信号分离的精度，为噪声治理方案优化提供理论依据。
[Abstract]:When people work in a high decibel noise environment for a long time, they will produce problems such as mental tension and distraction, which will affect people's physical and mental health and normal working efficiency. At the same time, the vibration will be transferred to the floor and enclosure, which will make the forced vibration produce secondary noise. The vibration and acoustic coupling produced by the floor structure will have an impact on the safety of the building. At present, the accuracy of large space acoustic field calculation is low, resulting in the noise control scheme is difficult to optimize, the treatment effect is not ideal. By collecting noise signals, the blind source separation algorithm is used to effectively and accurately separate the noise signals of the main equipment in large space, and the noise reduction scheme is optimized according to the spectrum characteristics of the noise signals. The vibration and acoustic coupling of the envelope structure and the main mechanical equipment is taken into account to achieve better vibration and noise reduction. First of all, comparing different blind source separation algorithms, considering the advantages of different algorithms as well as the characteristics of noise signal, the blind source separation algorithm is selected, which has the advantages of small computation, low complexity, and can effectively resist interference. The simulation results show that the blind source separation algorithm based on high order statistics is more accurate. In order to evaluate the accuracy of blind source separation better, the crosstalk error method suitable for noise signal characteristics in space is selected in this paper. Because the crosstalk error method can not accurately evaluate some special global matrices. Therefore, the traditional crosstalk error method is optimized, the variance and correlation coefficient of each element in the global matrix are introduced, the accuracy of the crosstalk error method for the special matrix is improved, and the influence of the strong interference signal in the space can be eliminated. The accuracy of noise field calculation is higher. On this basis, the real mixed noise signals are collected in the laboratory, and different noise signals are separated. The optimized crosstalk error method is used to evaluate the separation results, and the separation effect of the blind source separation algorithm is proved. Finally, the real mixed noise of a large supermarket underground water source heat pump machine room is collected, and the noise signals produced by different equipments are separated. The combined sound absorber and pipeline are adopted to reduce vibration and noise respectively. The hole diameter, perforation rate and thickness structure parameters affecting the sound absorption coefficient of the sound absorber were optimized. At the same time, the separation signal contains the secondary noise produced by the heat pump unit to the floor vibration, and the vibration-acoustic coupling model of the machine room is established, and the effect of the vibration-acoustic coupling on the sound field is taken into account according to the numerical simulation results. It is considered that the intermediate mass block of the two stage absorber has the greatest influence on the damping effect, and the parameter of the intermediate mass block of the damper is optimized to be 200 kg. The test results show that the vibration of floor slab is obviously weakened by the vibration absorber with optimized parameters, the noise value of heat pump room is reduced by 14.6 dB, the vibration amplitude is reduced from 4mm/s to 0.7 mm / s, and good vibration and noise reduction effect is achieved. The research improves the accuracy of noise signal separation in multi-equipment space and provides the theoretical basis for the optimization of noise control scheme.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB535

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