天然气集输站场流噪声研究

发布时间：2018-03-28 21:01

本文选题：流噪声　切入点：大涡模拟　出处：《西南石油大学》2015年硕士论文

【摘要】：天然气集输站场在调压计量、分输时,由于管内介质流动状态产生变化,涡流扰动随之形成,伴随着与管道壁面之间的摩擦,最终产生了流体动力性噪声,即流噪声。天然气集输站场的流噪声主要来源于钢质弯管、三通等部件以及汇管、调压阀、过滤分离器等设备。针对天然气集输站场流噪声超标问题,以大涡模拟与FW-H声比拟理论相结合的理论分析方法,开展站场不同弯头及汇管流噪声的形成机理与影响因素分析。引入小孔消声技术,建立相应的分析模型,结合流噪声计算结果,分析小孔消声器的有效性和适应性,并提出合理、有效的天然气集输站场流噪声防控措施,具体内容如下： (1)基于大涡模拟与FW-H声比拟理论相结合的天然气集输站场流噪声研究。通过对站场弯头、汇管流噪声的模拟分析,及其影响因素的讨论,验证了LES与FW-H声比拟理论相结合的分析方法在天然气集输站场流噪声研究方面的有效性。 (2)针对天然气集输站场常用弯头和汇管的流噪声问题,建立弯头、汇管流噪声计算模型,利用ANSYS Flu ent软件进行计算,分析流噪声声压级分布规律。计算分析结果表明：站场弯头内流噪声声压级最高为100dB、汇管内流噪声声压级高达110dB,均超出了国家规定的环境噪声等级(70dB)；弯头、汇管流噪声声压级所对应的频率分布范围较宽,各个频率都存在一定的声波能量,是一种宽频噪声。 (3)根据弯头流噪声声压级分布情况,建立不同结构的弯头模型,基于声场分析软件,对不同工况条件下的声压级变化进行研究。研究表明：弯头流噪声的发声机理主要是弯头处二次流以及涡流的作用,而随着弯头角度的减小或弯曲半径的增大,急变流的影响逐渐减小,能够有效控制弯头处的流噪声等级;伴随着压力每提升0.1MPa,弯头管段壁面附近的声压级提高1dB～3dB。 (4)对站场汇管进出气管相对或者错开两种不同连接方式的流噪声声压级的分布情况进行模拟计算,分析不同连接形式对声压级的影响。分析结果表明：汇管进出气管相错开连接时,随着进气管管径的减小,进气管末端的流噪声声能量逐渐增强、声压级逐渐增加,且增加幅度越来越大；汇管进出气管相对连接时,进气管末端喷射出流对汇管壁面的损害较低,且造成的冲击噪声更小。 (5)在合理确定天然气集输站场流噪声超标问题的基础上,建立汇管小孔消声器模型,设计了对应条件下的小孔消声器,其参数为：小孔孔径为3mm,小孔数量为480个,消声器管径与长度分别为60mm和650mm。在汇管进气管内安装小孔消声器,分析小孔消声器的降噪效果。结果表明：小孔消声器能够有效降低汇管内的流噪声声压级,对低频段声压级,降噪效果最高可达37.4dB,平均降噪20.9dB。
[Abstract]:In the pressure regulation and metering of natural gas gathering and transportation station, due to the change of the flow state of the medium in the pipe, the eddy current disturbance is formed, and with the friction between the pipeline wall and the wall of the pipeline, the fluid dynamic noise is finally produced. Flow noise. The flow noise of natural gas gathering and transportation station mainly comes from steel bend pipe, three-way connection and other equipment, such as sink pipe, pressure regulating valve, filter separator and so on. In view of the problem of excessive flow noise in natural gas gathering and transportation station, the formation mechanism and influencing factors of noise at different bends and sinks of station yard are analyzed by combining large eddy simulation with FW-H sound analogy theory, and the small hole silencing technique is introduced. This paper establishes the corresponding analysis model, analyzes the effectiveness and adaptability of the small hole muffler, and puts forward reasonable and effective measures to prevent and control the flow noise in the natural gas gathering and transportation station. The specific contents are as follows:. 1) based on the theory of large eddy simulation and FW-H acoustic analogy, the flow noise of natural gas gathering and transportation station is studied. It is verified that the analysis method combined with LES and FW-H acoustic analogy theory is effective in the research of flow noise in natural gas gathering and transportation station. 2) aiming at the flow noise problem of bends and sinks in natural gas gathering and transportation station, the calculation model of elbow and manifold noise is established, and the calculation is carried out by ANSYS Flu ent software. Analysis of the distribution of flow noise sound pressure level. The results show that the maximum noise sound pressure level of the elbow in the station yard is 100 dB, and the noise sound pressure level in the sink pipe reaches 110 dB, which exceeds the environmental noise level of 70 dB specified by the state. The frequency distribution range corresponding to the noise pressure level of manifold flow is relatively wide, and there is a certain acoustic energy in each frequency, so it is a kind of wide-band noise. According to the distribution of noise-sound pressure level of elbow flow, the bend model with different structure is established, and the sound field analysis software is used. The change of sound pressure level under different working conditions is studied. The results show that the sound mechanism of elbow flow noise is mainly due to the secondary flow at the bend and the effect of eddy current, but with the decrease of the angle of the elbow or the increase of the bending radius, The effect of sudden change gradually decreases and the noise level at the elbow can be effectively controlled, and the sound pressure level near the wall of the bend pipe increases by 1 dB with the pressure rising at 0.1 MPa. (4) simulating the distribution of the flow noise sound pressure level in the inlet and outlet pipes of the station yard, either relative to or staggered by two kinds of connection modes, The influence of different connection forms on the sound pressure level is analyzed. The results show that with the decrease of inlet pipe diameter, the flow noise sound energy at the end of the inlet pipe increases gradually, and the sound pressure level increases gradually when the inlet tube is staggered in and out of the pipe. When the inlet tube is connected with the inlet and outlet trachea, the ejection flow at the end of the inlet pipe causes less damage to the wall of the inlet tube and causes less impact noise. On the basis of reasonably determining the problem that the flow noise of natural gas gathering and transportation station exceeds the standard, the model of sink tube small hole muffler is established, and the small hole muffler under corresponding conditions is designed. The parameters are as follows: the aperture of small hole is 3 mm, the number of small hole is 480, The diameter and length of the muffler are 60mm and 650mm. the noise reduction effect of the muffler is analyzed by installing a small hole muffler in the intake pipe of the sink. The results show that the noise pressure level of the flow noise in the sink tube can be effectively reduced by the small hole muffler, and the sound pressure level in the low frequency band can be effectively reduced by the muffler. The highest noise reduction effect was 37.4 dB, and the average noise reduction was 20.9 dB.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE86;TB53

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