﻿ 基于FEM/BEM的船用水泵流动诱发振动噪声计算分析
 舰船科学技术  2016, Vol. 38 Issue (5): 49-55 PDF

FEM/BEM analysis for flow induced noise and vibration of a centrifugal pump
WU Jiang-hai, HE Tao, YIN Zhi-yong
China Ship Scientific Research Center, National Key Laboratory on Ship Vibration and Noise, Wuxi 214082, China
Abstract: Centrifugal pumps are important fluid machinery on ship, widely used in cooling system, bilge ballast system, circulating water systems, fire systems, etc. Centrifugal pump is also one noise source of ship pipeline, affecting the comfort and safety of the ship runtime environment. In this paper, Fluent is used to calculate the impeller suffered temporal fluctuation pressure during the unsteady flow period. The pressure load as an excitation source is applied to the pump motor finite element model and an implicit finite element method is used to calculate surface vibration and acceleration of the machine, and pump vibration intensity can be estimated. By importing the finite element vibration velocity into Virtual.Lab, using acoustic BEM air radiated noise of pump is calculated. The results show that: the noise of the outlet and the foot of pump is large and hence noise reduction technology is necessary.
Key words: centrifugal pump     vibration and noise     indirect BEM     acoustic radiation
0 引言

1 数值计算 1.1 水动力计算

 图 1 离心泵流场计算模型 Fig. 1 Numerical model of pump for hydrodynamic calculation

 图 2 离心泵原方案与优化方案静压分布 Fig. 2 Static pressure of antitype and advanced pumps

 图 3 离心泵原方案与优化方案湍动能分布 Fig. 3 Turbulent kinetic energy of antitype and advanced pumps

 图 4 离心泵原方案与优化方案叶轮流体三向激励力与力矩 Fig. 4 Time series of forces and moments on impeller of antitype and advanced pumps
1.2 水泵振动计算与模型

 图 5 泵组有限元模型 Fig. 5 Assembling of pump

 图 6 泵组模态计算 Fig. 6 Mode analysis of pump

 图 7 泵组机脚振动加速度 Fig. 7 Numercial results of acceleration on pump

 图 8 左上机脚振动速度 Fig. 8 Velocity of left upper point of pump

 ${{v}_{rms}}=\sqrt{\frac{1}{n}(v_{1}^{2}+v_{2}^{2}+v_{3}^{2}+.....+v_{n}^{2})}.$

2 边界元声辐射计算

 ${{\nabla }^{2}}p=\frac{1}{{{c}^{2}}}\frac{{{\partial }^{2}}p}{\partial {{t}^{2}}}.$

 ${{\nabla }^{2}}p+{{k}^{2}}p=0.$

 图 9 场点声压云图 Fig. 9 Pressure of field

1） 在 100 Hz 时，辐射球场上靠近离心水泵的出水口处的声压较大，这与前面模态计算中，出水处的振动最为剧烈而相吻合。

2） 在 300 Hz 时，辐射球场上靠近水泵机脚接地处的声压较大，对应于前面模态分析中出现的水泵支座的局部振动。

3） 在 500 Hz 时，辐射球场上对应出水口与支座处的声压值都很大，只有水泵左右两侧的声压还处于较小水平。

4） 在 640 Hz 时，辐射球场上整个声压值达到最大值，为 51.5 dB，整体舱内的声压都处于比较大的情况。

3 结语

1） 泵内汽蚀性能和流体脉动压力为流动诱发噪声和振动的主要来源，其汽蚀性能的优化和流体脉动压力的降低是低振动噪声水泵优化的目标；

2） 泵体在振动中，出口法兰处与电机机脚处的振动最为剧烈，应加强隔振器的刚度以及泵组安装的平稳性；

3） 泵组产生的噪声主要在几个频率点上，应当调整泵体的机械结构，避免与上述频率产生共振，从而加大泵体声辐射。

 [1] 高新民, 陈冰, 吕敬高, 等. 船用离心泵减振降噪分析[J]. 流体机械 , 2011, 39 (9) :50–53. GAO Xin-min, CHEN Bing, LV Jing-gao, et al. Analysis on reducing vibration and noise of centrifugal pump using in ships[J]. Fluid Machinery , 2011, 39 (9) :50–53. [2] 何涛, 尹志勇, 孙玉东. 离心泵流动诱发振动特性数值计算分析[J]. 振动与冲击 , 2012, 31 (12) :96–102. HE Tao, YIN Zhi-yong, SUN Yu-dong. Numerical analysis for flow induced vibration of a centrifugal pump[J]. Journal of Vi-bration and Shock , 2012, 31 (12) :96–102. [3] 黄国富, 常煜, 张海民. 低振动噪声船用离心泵的水力设计[J]. 船舶力学 , 2009, 13 (2) :313–318. HUANG Guo-fu, CHANG Yu, ZHNAG Hai-min. Hydraulic redesign on a marine centrifugal pump for hydro-borne vibration and noise reduction[J]. Journal of Ship Mechanics , 2009, 13 (2) :313–318. [4] BOLTON N. Noise generation in pumps[M]//Noise in fluid machinery[M]. London, UK:I Mech E Seminar Publication, 1999. [5] GüLICH J F. Centrifugal pumps[M]. Berlin Heidelberg: Springer, 2010 . [6] 叶建平.离心泵振动噪声分析及声优化设计研究[D].武汉:武汉理工大学, 2006. YE Jian-ping. Research on optimization of vibration and structural noise of centrifugal pump[D]. Wuhan:Wuhan University of Technology, 2006. [7] 黄国富, 常煜, 张海民. 基于CFD的船用离心泵流体动力振动噪声源分析[J]. 水泵技术 , 2008 (3) :20–24. HUANG Guo-fu, CHANG Yu, ZHNAG Hai-min. Analysis on vibration and noise of centrifugal pump based on fluent[J]. Pump Technology , 2008 (3) :20–24. [8] LANGTHJEM M A, OLHOFF N. A numerical study of flow-induced noise in a two-dimensional centrifugal pump. Part II. Hydroacoustics[J]. Journal of Fluids and Structures , 2014, 19 (3) :369–386.