﻿ 基于流固耦合的桨轴系统横向振动特性研究
 舰船科学技术  2022, Vol. 44 Issue (1): 34-38    DOI: 10.3404/j.issn.1672-7649.2022.01.007 PDF

1. 中国舰船研究设计中心 船舶振动噪声重点实验室，湖北 武汉 430060;
2. 武汉理工大学 能源动力学院，湖北 武汉 430063

Research on the lateral vibration characteristics of propeller-shaft system based on fluid-solid coupling
SHEN Li-jiao1, JIN Yong2
1. National Key Laboratory on Ship Vibraion and Noise, China Ship Development and Design Center, Wuhan 430060, China;
2. School of Energy and Power Engineering, Wuhan University of Technology, Wuhan 430063, China
Abstract: With the development of large-scale and high-speed ships, the working load of propeller-shaft system becomes more massive, and the dimension increases, the Lubrication State of the tail bearing will change the supporting characteristics of shaft system. The lateral vibration, which is sensitive to the support system, is more easily affected. In this paper, the solid model of tail bearing is established, and the lubrication characteristic model of water-lubricated bearing is established by using multi-support. Compared with the traditional single-point support, the lateral vibration characteristic of the shaft system based on the fluid-solid coupling is calculated, and the fluid-solid coupling model can reflect closely the natural vibration characteristics of the shafting.
Key words: propeller-shaft system     FSI     water-lubricated stern bearing     lateral vibration
0 引　言

1 横向振动分析 1.1 传统方法

 图 1 某长轴系单点虚拟支撑振动分析模型 Fig. 1 Vibration analysis model of a long shafting system with single point virtual support

1.2 基于流固耦合的计算模型

 图 2 某长轴系尾轴承实体振动分析模型 Fig. 2 Vibration analysis model of a long shafting system with solid stern bearing

1）尾轴承的液膜压力分布

 图 3 水润滑轴承液膜压力分布计算 Fig. 3 Calculation of pressure distribution of liquid film in water-lubricated bearings

2）添加水膜压力

 图 4 轴颈处水膜压力 Fig. 4 Water film pressure at journal

3）液膜动态刚度

 $K_{x x}=\frac{\partial F_{x}}{\partial x} , K_{x y}=\frac{\partial F_{x}}{\partial y} , K_{y x}=\frac{\partial F_{y}}{\partial x} , K_{y y}=\frac{\partial F_{y}}{\partial y} \text{。}$ (1)

2 有限元数值计算 2.1 模型参数

 图 5 长轴系示意图 Fig. 5 Diagram of a long shafting

2.2 仿真分析结果与讨论

 图 6 虚拟单点支撑有效弯曲模态振型图 Fig. 6 Effective bending mode shape diagram with single point virtual support

 图 7 实体轴承模式有效弯曲模态振型图 Fig. 7 Effective bending mode shape diagram with solid bearing

 图 8 固有频率随转速的变化曲线 Fig. 8 The curve of natural frequency as a function of rotational speed

3 结　语

1）轴系转速变化，支撑特性也会变化，而基于流固耦合的轴系振动计算模型能得出这种固有频率的变化趋势，因此，流固耦合实体模型的处理方式更能反映出真实的轴系振动特性。

2）在流固耦合的实体模型下，应力强化作用以及液膜动态刚度都使得轴系的弯曲振动固有频率提高。

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