气田井口节流管道气动噪声及降噪研究

发布时间：2018-02-12 12:16

本文关键词： 井口节流管道气动噪声声振耦合辐射噪声降噪　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：四川磨溪气田在开采过程中,存在噪声严重超标的问题,噪声最高达110dB,远远超过国家标准中规定的噪声排放值。高噪声环境不仅影响井场周边工人的正常工作,同时还会给生产安全造成严重危害。对井场噪声进行深入研究,不仅具有非常重要的理论和实际意义,而且具有较为明显的经济效益和社会效益。本文以气田井口节流管道为研究对象,通过对其进行气动噪声和声振耦合的数值模拟分析,研究不同结构和不同工况下对节流管道气动噪声和节流管道声辐射的影响;并在此基础上,提出了合理、有效的降噪方案,并应用于现场取得了很好的降噪效果。本文主要从以下几个方面开展研究工作:(1)弯管和变径管气动噪声的产生机理。以大涡模拟和Lighthill声学类比相结合的方法为基础,分析弯管和变径管气动噪声的产生机理。弯管段气动噪声产生的主要原因是由于二次流和涡流的存在,而变径管噪声产生的主要原因是由于涡流的存在。并且弯管和变径管的气动噪声都是一种没有明显主频且在很多频率下都有声波能量的一种宽频噪声。(2)管道结构和工况对气动噪声的影响规律。通过分析弯管弯曲半径、弯曲角度以及运行工况对弯管气动噪声的影响规律,可以得到,增大弯曲半径和减小弯曲角度,能够减小弯管内气动噪声值。弯管半径由R=D增加到R=3D时,总声压级最大下降8.98dB,弯管角度由90°增大至150°时,总声压级最大下降4.79dB。弯管内压力对噪声的影响较小,而弯管内速度对声压级影响较大,可通过降低管内流速来控制噪声,管内流速尽量控制在10m/s以下。针对变径管气动噪声的分析可以得到,变径管中可通过减小变径管圆锥角来降低噪声。(3)节流管道气动噪声的声辐射规律。通过建立管道内部声腔—管壁结构—外部声场的声振耦合模型,可以得到,在声学载荷的激励下管道在117Hz附近与声腔发生共振。管壁厚度每增加1mm,最大振幅平均减少约0.02mm,最大声压级减小6.7dB,平均声压级减小5.07dB,最大声辐射功率级减小7.54dB,平均声辐射功率级减小6.31dB;弯曲半径每增加0.5D,最大振幅平均减少约0.02mm,最大声压级减小7.94dB,平均声压级减小5.97dB,最大声辐射功率级减小8.30dB,声辐射功率级减小6.70dB;增加管道约束可以提高管道刚度,大幅降低管道振动位移,减小噪声辐射。(4)结合第三章和第四章的研究内容,提出降噪方案并应用于现场。针对井场提出主动降噪和被动降噪两种降噪方案,并应用于现场,取得了很好的降噪效果,验证了方案的可行性。
[Abstract]:In the production process of Moxi gas field in Sichuan Province, there is the problem of serious noise exceeding the standard. The maximum noise is 110 dB, which far exceeds the noise emission value stipulated in the national standard. The high noise environment not only affects the normal work of the workers around the well site, At the same time, it will also cause serious harm to production safety. It is not only of great theoretical and practical significance to conduct in-depth research on well site noise, And it has obvious economic and social benefits. In this paper, the well head throttling pipeline in gas field is taken as the research object, and the numerical simulation analysis of the coupling of pneumatic noise and acoustic vibration is carried out. The effects of different structures and working conditions on the aerodynamic noise and acoustic radiation of throttling pipes are studied, and a reasonable and effective noise reduction scheme is proposed. In this paper, the mechanism of aerodynamic noise in the bend tube and the variable diameter tube is studied from the following aspects. Based on the method of large eddy simulation and Lighthill acoustics analogy, This paper analyzes the mechanism of aerodynamic noise in curved pipe and variable diameter tube. The main cause of aerodynamic noise in bend pipe is the existence of secondary flow and eddy current. The main reason for the noise of variable diameter tube is the existence of eddy current, and the aerodynamic noise of curved tube and variable diameter tube is a kind of wide band noise with no obvious main frequency and sound wave energy at many frequencies. By analyzing the bending radius of bends, The influence of bending angle and operating condition on the aerodynamic noise of the bend tube can be obtained by increasing the bending radius and decreasing the bending angle, which can reduce the aerodynamic noise value in the bend pipe. When the total sound pressure level is decreased by 8.98 dB and the angle of the elbow is increased from 90 掳to 150 掳, the maximum total sound pressure level decreases by 4.79 dB. The pressure in the bend tube has little effect on the noise, while the velocity in the bend tube has a great effect on the sound pressure level, so the noise can be controlled by reducing the velocity of flow in the pipe. The velocity of flow in the tube is controlled below 10 m / s. The analysis of the aerodynamic noise of the variable diameter tube can be obtained. In the variable diameter tube, the acoustic radiation law of the aerodynamic noise of the throttle pipe can be reduced by reducing the tapered angle of the variable diameter tube. By establishing the acoustic-vibration coupling model of the inner cavity, the structure of the pipe wall and the external sound field, it can be obtained. The tube resonates with the cavity in the vicinity of 117Hz under the excitation of acoustic load. When the thickness of the tube wall increases by 1 mm, the maximum amplitude decreases by about 0.02 mm, the maximum sound pressure level decreases by 6.7 dB, the average sound pressure level decreases by 5.07 dB, the maximum sound radiation power level decreases by 7.54 dB, and the average maximum acoustic radiation power level decreases by 7.54 dB. The maximum amplitude decreases about 0.02mm, the maximum sound pressure level decreases 7.94 dB, the average sound pressure level decreases 5.97 dB, the maximum sound radiation power level decreases 8.30 dB, and the acoustic radiation power level decreases 6.70 dB for every 0.5 Dd of bending radius. To increase the stiffness of the pipe, According to the research contents of Chapter 3 and Chapter 4th, the noise reduction scheme is put forward and applied to the field. Two kinds of noise reduction schemes, active noise reduction and passive noise reduction, are put forward for well field, and they are applied in the field. A good noise reduction effect is obtained and the feasibility of the scheme is verified.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB535;TE931.1

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