论文总字数：25108字

摘 要

近年来，随着多相流泵的应用越来越广泛，人们逐渐发现：多相流泵的噪声要远大于单相流情况下的噪声。所以，离心泵内气液两相流动噪声已经成为一个大家十分关心的问题。为了研究不同进口含气率（IGVF）对离心泵内流动诱导噪声的影响，本文主要基于CFX软件对离心泵内低转速工况下的气液两相流进行了数值计算，并且还对额定转速工况下的气液两相流动诱导噪声进行了数值预测。研究得到的结果对降低气液两相流泵内流动诱导噪声具有一定的参考价值。

本文的主要内容及结论如下：

（1）简述了本课题的研究背景、研究内容以及发展趋势，详细地介绍了流体流动数值模拟和声学数值模拟的具体方法。在研究具体针对诱导噪声的求解方法时，提出了声学边界元法是一种典型的针对噪声的求解方法，并阐述了声学模型的选择和网格的划分。

（2）研究了不同含气率对离心泵外特性的影响，分析和比较了离心泵内不同含气率时的气体分布图、速度云图及流场图、湍动能分布图和压力脉动频域分析图。探讨了模型泵内压力脉动变化的规律，结果表明：随着含气率增加，泵内扬程呈下降趋势，模型泵的工作能力也会随之降低。

（3）研究计算了离心泵流动噪声内声场及声振耦合外声场的计算，分析了蜗壳结构体模型及其模态的求解方法，探讨了声振耦合的计算方法，并对其计算结果做了总结分析。结果表明：在气液两相流动下，作用于模型泵壳体的激振力机理更为复杂；模型泵内流动诱导辐射噪声会在纯水状态中表现出一定的由于模型泵内动静干涉效应引起的特征。

关键词：含气率；离心泵；数值模拟；声振耦合；声场

Abstract

In recent years, with the application of multiphase flow pump more and more widely, people have gradually found that the noise of multiphase flow pump is much higher than that of single-phase flow. Therefore, the gas liquid two phase flow noise in centrifugal pump has become a very concerned problem. In order to study the influence of IGVF on flow induced noise in the centrifugal pump, this dissertation carried out numerical calculation of gas-liquid two-phase flow in the centrifugal pump at low speed based on CFX software, and carried out numerical prediction of gas-liquid two-phase flow induced noise at rated speed. The results of the study have some reference value for reducing the flow-induced noise in the gas-liquid two-phase flow pump.

The main contents and conclusions of this dissertation are as follows:

(1) The research background, research content and development trend of this subject were briefly introduced, and the specific methods of fluid flow numerical simulation and acoustic numerical simulation were introduced in detail. The acoustic boundary element method was a typical method for solving induced noise, and the selection of acoustic model and the division of mesh were discussed.

(2) The influence of different gas holdup rates on the characteristics outside the centrifugal pump was studied, and the gas distribution diagram, velocity cloud diagram, flow field diagram, turbulent kinetic energy distribution diagram and pressure pulsation frequency domain analysis diagram of different gas holdup rates in the centrifugal pump were analyzed and compared. The law of pressure pulsation in the model pump was discussed .The results show that with the increase of gas hold up, the head of the pump decreases and the working capacity of the model pump decreases.

(3) The calculation of internal sound field and external sound field coupled with flow noise of centrifugal pump was studied and calculated. The calculation method of volute structure model and its mode was analyzed. The calculation method of acoustic coupling was discussed. The calculation results were summarized and analyzed. The results show that the mechanism of excitation force acting on the model pump shell is more complex under the condition of gas-liquid two-phase flow. In the pure water state, the fluid-induced radiation noise in the model pump will show some characteristics caused by the rotor-stator interference effect in the model pump.

Keywords: Gas rate; Centrifugal pump; Numerical simulation; Acoustic coupling; Sound field

目 录

摘 要 I

Abstract II

第一章 绪论 1

1.1 本课题的研究背景 1

1.2 本课题的研究意义 1

1.3 本课题的研究现状 3

1.4 本课题的研究内容 4

1.5 本课题采用的研究方法 4

第二章 泵内气液两相流动非定常数值模拟方法 6

2.1 流体流动数值模拟方法 6

2.1.1 流体域的三维建模 6

2.1.2 流体域的网格划分 6

2.1.3 控制方程 8

2.1.4 计算方法 9

2.1.5 初始条件 9

2.1.6 监测点的设置 10

2.2 声学数值模拟方法 10

2.2.1 噪声声源 11

2.2.2 噪声的求解方法 12

2.2.3 声学模型的选择 12

2.2.4 网格的划分与声源的设置 13

2.3 本章小结 13

第三章 气液两相流动数值计算结果分析 14

3.1 含气率对离心泵外特性的影响 14

3.2 模型泵内气体分布 14

3.3 速度云图及流场 15

3.4 湍动能分布 16

3.5 压力脉动频域分析 17

3.6 本章小结 19

第四章 离心泵流动噪声内声场及声振耦合外声场计算 20

4.1 蜗壳偶极子源内声场计算 20

4.2 声振耦合计算外场辐射声压 21

4.2.1 蜗壳结构体模型及模态求解 21

4.2.2 声振耦合计算结果及分析 22

4.3 本章小结 24

第五章 结论与展望 25

5.1 结论 25

5.2 展望 26

第六章 经济性评估 27

参考文献 28

致谢 31

第一章 绪论

1.1 本课题的研究背景

泵作为一种广泛使用的机械，我们几乎可以认为：凡是有液体流动的地方都离不开离心泵的工作^[1]。更加具体地来说，泵的使用范围已经广泛涉及到人民群众的日常生活。大到排洪抢险救灾，到我国的大型国民经济命脉的工作场合，如南水北调；小到家庭用水，如农业灌溉。从这里可以看出，泵与人们的生活息息相关，并且在这些活动过程中扮演着不可或缺的角色。它早已经和经济发展、人们的生活紧密联系在一起。但是根据不同的需要，泵也有着不同的类型。在众多类型的泵之中，离心泵是应用最广泛的一种，尤其是在化工生产中。这是因为离心泵具有应用范围广、体积小、结构简单、操作方便、流量均匀、故障少、使用寿命长、采购和运行成本低等突出优点。

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