摘 要

螺旋桨作为船舶的主要推进器，其具有复杂的曲面形状，加工难度较大，易产生加工误差，而加工误差会影响螺旋桨的水动力及低频线谱噪声性能，本文即针对加工误差对螺旋桨的水动力及低频线谱噪声性能的影响进行研究。

本文基于计算流体力学软件STAR-CCM 对螺旋桨的敞水性能进行了数值预报，并与实验值对比来验证计算方法的有效性。在此基础上，在均匀进流和非均匀进流两种条件下对主桨叶在六个自由度方向加工误差量的螺旋桨的水动力性能进行了计算，并据此系统分析了加工误差对螺旋桨轴承力的影响，探索了这一影响的初步规律。其主要工作如下：

（1）在均匀进流条件下，螺旋桨的轴承力大小随主桨叶沿各自由度方向加工误差量的增加呈线性增加的趋势，而主桨叶的加工误差不会在螺旋桨的轴向产生轴承力。主桨叶在直径、螺距方向的加工误差对螺旋桨轴承力影响较大，在轴毂长度方向的误差影响较小。

（2）在非均匀进流条件下，随着各自由度方向加工误差量的增加，垂向和横向轴频轴承力呈现线性增加的趋势，尤其是在直径、螺距方向的误差对其影响较大。主桨叶沿直径方向改变约1%D时产生的轴频轴承力为伴流产生的一阶叶频轴承力的3.3倍。主桨叶沿螺距角方向改变约2^o时产生的轴频轴承力为伴流产生的一阶叶频轴承力的7.5倍。

（3）以几种典型工况为例计算并分析了加工误差对螺旋桨低频线谱噪声的影响。通过计算发现，在均匀进流条件下，随着螺旋桨主桨叶在螺距角方向加工误差量的增加，桨盘面径向各点的叶频噪声有微小的增加，同时产生轴频噪声，且轴频噪声的增加幅度远大于叶频噪声。随着声压级监测点到桨盘面中心距离的增加，轴频噪声桨逐渐超过叶频噪声。据此认为,螺旋桨的加工误差对其低频线谱噪声存在明显影响。

本文通过数值模拟的方法探索了加工误差对螺旋桨水动力及低频线谱噪声性能影响的初步规律。了解这些规律对于准确预报螺旋桨性能具有重要意义，同时也有助于为螺旋桨的加工精度提出更详细的规范和准则。

关键词：螺旋桨；加工误差；计算流体动力学；轴承力；噪声

Abstract

The propeller which is main propulsion of the ship has complicated surface shape and difficult processing,and it is prone to machining error.The machining error will affect the propeller hydrodynamics and low-frequency line-spectrum noise performance,and the propeller hydrodynamics and low-frequency line spectrum performance influenced by the machining error was studied by this paper.

The open water performance was predicted numerically based on the CFD software STAR-CCM ,and the validity of the numerical method was verified by comparing with the experimental value. Then the influence of mismachining error for propeller bearing force was calculated and analyzed by changing propeller blade in six degrees of freedom in uniform and non-uniform flow condition in order to explore the preliminary rule which mismachining error influenced the bearing force of propeller.The main work of paper are below:

(1)The bearing force of propeller is linear increasing with the increase of the mismachining error along the various degree of freedom and the mismachining error of blade will not generate axial bearing force in uniform flow condition.The mismachining error of main blade in the direction of the diameter and pitch has a relatively large influence on bearing force of propeller,and The mismachining error of main blade in the direction of the hub has a relatively small influence on bearing force of propeller,

(2)Vertical and transverse axis frequency bearing force has a linear increase with the increase of the mismachining error in the direction of six degrees of freedom in non-uniform flow condition,and ,the mismachining error of main blade in the direction of the diameter and pitch has a especially large influence on bearing force of propeller;The axis frequency bearing force produced by the main blade which has a mismachining error about 1%D along diameter direction is 3.3 times than the first-oreder blade frequency bearing force produced by the wake; The axis frequency bearing force produced by the main blade which has a mismachining error about 2^o along pitch angle direction is 7.5 times than the first-oreder blade frequency bearing force produced by the wake.

(3)the mismachining tolerance influence of low-frequency line-spectrum noise of the propeller was calculated and analyzed in certain kinds of typical conditions in a limited time. We cailculated that with the increasing mismachining error of the main blade in pitch angle direction

, the blade frequency noise has a small increase in various radius of the propeller disk of radial direction and shaft frequency noise was produced at the same time,and the propeller shaft frequency noise has a larger increse than the propeller balde frequency noise.With the increse of distance about the monitoring point of the sound pressure level to the propeller disk,the axial frequency noise gradually surpass the propeller blade frequency noise. Accordingly,the machining error of propeller has an obvious influence on the low frequency line-spectrum noise.

This paper analyzed the preliminary rule which mismachining error influenced the propeller hydrodynamics and low-frequency line-spectrum noise performance by numerical method.Grasping these rules is of great significance for predicting propeller performance accurately and contributes to put forward more detailed specifications and standards for machining precision of propeller.

Key words:propeller; mismachining error; CFD；bearing force;noise

目录

摘要 I

Abstract II

第1章 绪论 1

1.1研究背景 1

1.2国内外研究现状 2

1.2.1 CFD在螺旋桨敞水性能方面的研究进展 2

1.2.2 CFD在螺旋桨轴承力方面的研究进展 3

1.2.3 CFD在螺旋桨噪声方面的研究进展 3

1.3本文主要工作 3

第2章 基于CFD的敞水螺旋桨数值模拟 5

2.1 CFD简介 5

2.1.1RANS方法 5

2.1.2湍流模型介绍 7

2.1.3 STAR-CCM 简介 8

2.2螺旋桨计算模型的建立 9

2.2.1 螺旋桨几何建模 9

2.2.2计算域及其网格 13

2.2.3计算设置 14

2.3敞水性能计算结果 14

2.3.1外特性 14

2.3.2流场分析 15

2.4本章小结 19

第3章均匀进流时加工误差对轴承力影响的计算 20

3.1轴承力谐调分析方法 20

3.2计算方法 23

3.3加工误差对轴承力的影响 23

3.3.1概述 23

3.3.2计算结果 24

3.4本章小结 29

第4章 非均匀进流时加工误差对轴承力影响的计算 30

4.1艇尾伴流场计算 30

4.1.1计算对象 30

4.1.2 边界条件及网格 33

4.1.3计算结果 35

4.2计算方法 37

4.2.1 概述 37

4.2.2数值方法和网格划分 37

4.2.3可靠性验证 44

4.3计算结果 46

4.4本章小结 53

第5章加工误差对螺旋桨低频线谱噪声影响的数值预报 55

5.1螺旋桨流噪声计算理论基础 55

5.1.1引言 55

5.1.2 Ffowcs Williams -Hawkings方程 55

5.2螺旋桨流噪声计算过程 56

5.3加工误差对低频线谱噪声影响的数值预报 58

5.3.1数值模型 58

5.3.2可靠性验证 58

5.3.3加工误差对低频线谱噪声影响的数值预报 59

5.4本章小结 60

第6章 结论 61

6.1小结 61

6.2展望 61

参考文献 63

致谢 65

附录A 4119螺旋桨详细参数 66

附录B 傅里叶变换程序 67