船舶管路气动噪声数值模拟及优化设计

发布时间：2019-05-06 08:12

【摘要】：现代舰船内部分布着众多保证船舶正常工作的管路系统,这些管路系统在正常工作的同时,也带来了不容忽略的噪声问题,对工作在船上的人员造成了困扰。而这其中通风管路由于直接与船上的生活舱室相连通,由此而来的气动噪声问题就显得格外重要。船上的管路形式多样,包括圆管、方管,直管、弯管以及直角弯管、圆角弯管。由于船舶管路长度长、分布广且形式复杂的特点,一直以来对船上管路气动噪声的预测都是一个难点。本文首先对船上复杂的管路系统的特点进行了归纳,抽象出了几种船上常见的管路模型；然后应用计算流体力学的方法,使用大型流体仿真软件Fluent对通气管路模型内部流场进行了瞬态计算,得到了时域下管壁内部的脉动压力分布,然后将得到了时域结果导入声学计算软件LMS Virtual.Lab Acoustics进行声学有限元计算,得到管路声压云图及出口监测点处的气动噪声声压级曲线。并对不同的管路模型进行对比分析,得到管路气动噪声规律以及更加优化的船舶管路形式,可为船舶舱室噪声的计算提供通气管路气动噪声数据。计算结果表明,对于船上通气管路,圆管的气动噪声水平要低于方管,因此圆管的气动噪声特性要好于方管；圆角弯的气动噪声水平要低于直角弯,且随圆角弯管的弯角半径增大,气动噪声降低。因此船上管路设计应尽可能使气流的流动均匀,应避免急转弯,尽量采用圆角弯头代替直角弯头。降低船舶管道内气动噪声的最主要措施是限制管道内的风速,根据本文计算,管道内风速增大一倍,出口监测点处气动噪声声压级增大14—15分贝。由于根据相关规范,主管内的风速一般应不大于10m/s,对噪声要求严格的管路系统中主管道内的风速可控制在5m/s左右。
[Abstract]:There are many pipeline systems to ensure the normal operation of ships in modern ships. These piping systems also bring about noise problems which can not be ignored, and cause trouble to the personnel working on the ship. Because of the direct connection between the ventilation pipe and the cabin of the ship, the aerodynamic noise problem becomes more and more important. There are various types of pipeline on board, including round pipe, square pipe, straight pipe, bend pipe and right-angle pipe, and round-fillet pipe. Because of the long length, wide distribution and complicated form of ship pipeline, it is difficult to predict the aerodynamic noise of ship pipeline. In this paper, the characteristics of complex pipeline system on board are summarized, and several common pipeline models on board are abstracted. Then using the method of computational fluid dynamics (CFD) and using the large-scale fluid simulation software Fluent, the transient flow field in the ventilation pipeline model is calculated, and the fluctuating pressure distribution in the pipe wall in the time domain is obtained. Then the time-domain results are imported into the acoustic calculation software LMS Virtual.Lab Acoustics for acoustic finite element calculation, and the sound pressure cloud map of the pipeline and the pressure level curve of aerodynamic noise at the outlet monitoring point are obtained. By comparing and analyzing the different pipeline models, the aerodynamic noise law of the pipeline and the more optimized form of the ship pipeline can be obtained, which can provide the aerodynamic noise data of the ventilated pipeline for the calculation of the cabin noise of the ship. The results show that the aerodynamic noise level of the circular tube is lower than that of the square tube, so the aerodynamic noise characteristic of the circular tube is better than that of the square tube. The aerodynamic noise level of the fillet bend is lower than that of the right corner bend, and the aerodynamic noise decreases with the increase of the fillet radius of the fillet bend. Therefore, the pipeline design of the ship should make the flow of air flow uniform as far as possible, avoid sharp turning, and adopt the round corner elbow instead of the right angle elbow as far as possible. The most important measure to reduce the aerodynamic noise in the ship pipeline is to limit the wind velocity in the pipeline. According to the calculation in this paper, the wind speed in the pipeline is doubled and the sound pressure level of aerodynamic noise at the outlet monitoring point is increased by 14 ~ 15 decibels. According to the relevant specifications, the wind speed in the main pipe should not be more than 10 mm2, and the wind speed in the main pipe can be controlled to about 5m/s when the noise requirement is strict.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U661.44;U664.84

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