叶片数及叶轮流道形状对离心泵流动激励力与诱导噪声的影响

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摘要

离心泵在运行的过程当中，由于水泵的机械结构以及内部的流体运动均能使激

励力改变，从而产生振动和噪声，对周围环境造成影响。按照噪声产生机理可以

分为机械结构振动噪声和流体激励产生的噪声。其中机械噪声主要由水泵叶轮及

轴的不对称和不对中引起的；而流体激励产生的噪声则与离心泵内非定常流动引

起的叶片表面、蜗室内表面的压强脉动及泵内涡流密切相关。叶轮作为离心泵的

核心工作部件，其叶片数及叶轮子午流道形状对离心泵的性能及非定常流场脉动

有着重要影响，从而影响离心泵的流动激励及其诱导的噪声。本文基于混合数值

模拟方法研究上述因素对离心泵内流动激励力与噪声的影响。混合数值模拟方法

是目前进行声场预测的常用方法，该方法忽略声场对流场的反作用，首先采用计

算流体力学方法获得非定常流场的数值解，提取流场内的脉动压强为声源，然后

通过求解声学方程获得声场。为了考虑非定常流场激励引起的离心泵结构振动与

声场的相互耦合作用，本文在声场的求解过程中，采用 LMS Virtual.Lab 的声振耦

合模块进行声场求解。主要研究内容如下：

1. 采用 RNG K-ε和大涡模拟模型对离心泵内三维粘性定常和非定常流场进行计

算，并依据离心泵的性能曲线和蜗室内的压强信号对离心泵定常流场与非定常

流场数值解的网格无关性进行了讨论。

2. 在原模型的基础上，保证蜗室、叶轮出口直径、宽度不变，利用水泵相似原理

设计了与原模型额定工况相同的离心泵，两个离心泵的叶轮流道、叶型、叶片

数均不相同，分别为 5和6；然后根据原始水泵模型，令叶片数分别为 6和7，

获得两款新的离心泵。本文对上述四个离心泵模型的性能、非定常流场以及流

动激励引起的声场进行了数值模拟，结果表明：对于叶轮参数相同的离心泵，

叶片数为 7的离心泵扬程较叶片数等于 6和5的离心泵高约 0.5m 和2m 左右。

其蜗壳壁面监测点的压力脉动较后两个模型提高 8.54%和21.14%。同时在叶频

下随叶片数增加蜗壳振动加速度逐渐增大，然而在其他频率下不明显，这是由

于外场辐射噪声与壳体的结构模态关系密切。

3. 利用数值模拟方法对叶轮前盖板转角半径 RT/D2分别为 0.1、0.15 和0.2 的三个

离心泵流场与声场进行计算，数值计算结果表明：随着 RT/D2逐渐变大，离心

泵蜗室内压强脉动和叶轮受到流动激励力先增加后减小。RT/D2等于 0.2 的离

心泵模型蜗舌监测点压力脉动较等于 RT/D2=0.1 离心泵高出 1.2%。在叶频和第

三阶谐频下，RT/D2最大的离心泵壳体振动最剧烈，导致辐射噪声提高，该离

心泵出口处位置在叶频下的辐射噪声为 49dB。

4. 本文在蜗室及叶轮其他参数不变的条件下，对三个具有不同叶片前缘起始位置

的离心泵流场和声场进行计算，获得了离心泵的性能、泵内非定常激励力以及

流动激励诱导的振动与噪声。结果表明：随着叶片前缘位置逐渐远离水泵进口，

离心泵蜗室内压强脉动逐渐减弱而叶轮受到流动激励却逐渐升高。叶片前缘位

置距离心泵进口最远的水泵模型叶轮受到的径向力脉动较最近的水泵高出

2.41%。由声场分析可知，距离心泵进口最远的离心泵模型在前三阶频率下蜗

壳振动加速度最大，在叶频下，90°~120°方向上其辐射噪声达到 50dB。

关键词：离心泵压力脉动流动激励力振动加速度流动诱导噪声

Abstract

The vibration and noise are caused by pressure fluctuation of the fluid in centrifugal

pump as working, which affect the environment. Therefore, it’s essential to study the

flow exciting force to reduce and control the vibration and noise of the centrifugal

pumps. According to the mechanism of noise generation, the noise can be divided into

mechanical and flow-induced noises. The mechanical noises are generated by the

asymmetry and misalignment of impeller and shaft, while the flow-induced noises

almost come from the unsteady flow, which is closely relate to pressure fluctuation

acting on the blade and volute. Impeller is the most important part of the centrifugal

pump, blade numbers and the meridional channels of which impact significantly on the

pressure fluctuations of centrifugal pump. The factors affecting the flow exciting force

and noise in centrifugal pumps are researched based on a hybrid numerical approach in

the thesis. Hybrid numerical simulation approach is widely used for the prediction of

the sound field, which ignores the action of the sound field on the flow. Firstly, the

numerical solution of the unsteady flow field should be obtained by computational fluid

dynamics method. Then, the pressure fluctuations on the volute and blades are extracted

as the sound source, and the noise radiation is calculated by solving the acoustic

equation. The acoustic coupling module of LMS Virtual. Lab is applied in this paper to

simulated the coupling effect of the structure vibration and the sound field. The work

and results of this thesis are listed as follows:

1. RNG K-εand Large eddy simulations are employed to calculate the steady and

unsteady flow respectively. The flow field of centrifugal pump is calculated with

different grid cells to analyze the influence of computational grid number on the

numerical solution.

2. A centrifugal pump with a six-blade impeller is chosen as the prototype pump, a

new pump with five-blade impeller is designed at the same performance parameters

and the volutes . Then two other centrifugal pumps with six and seven blades

impellers are chosen which have the same blade type and meridional channel as the

prototype pump. The hydraulic performance, unsteady flow performance and the

radiate noise of the four centrifugal pumps are analyzed. The results show that the

head of pump with seven blades is higher than that with six and five blades about

0.5m and 2m respectively for the case of the same impeller shape. The pressure

fluctuation is also higher about 8.54% and 21.14% respectively. The acceleration of

volute is gradually increase at blade frequency, but the result at other frequencies is

not obvious. This is closed related to the radiated noise and the structure of shell.

3. The numerical simulation method is adopted to analysis the flow and sound field of

three centrifugal pumps, the front shroud corner radius RT/D2 of which are 0.1, 0.15

and 0.2 respectively. The results show that the pressure fluctuation and the

components force of impellers are irregularity with the increase of RT/D2. The

pressure fluctuation of the pump with RT/D2equals 0.2 is higher than that pump with

RT/D2equals 0.1 about 1.2%. The pump with the highest RT/D2 whose casing

vibration is the most dramatic which lead to the radiation noise improve at the first

and third frequency. The radiation noise is 49dB at the outlet of this centrifugal

pump under the blade frequency.

4. Three centrifugal pumps with different location of blade inlet which have the same

volute and impeller geometry shape. In order to obtain the hydraulic performance,

unsteady flow exciting force and radiate noise of centrifugal pumps, the numerical

simulation of three-dimensional viscous flow and acoustic field is calculated. The

results show that the pressure fluctuation of volute is decrease while the components

force of impellers are opposite with the position of the leading edge of blade

gradually away from the inlet of centrifugal pump. The fluctuation of the radial

force of the pump which the blade leading edge located the furthest away from the

inlet is 2.41% higher than the nearest one. At the same time, the pump with the

farthest distances to the pump inlet whose vibration acceleration is the largest at the

first three frequencies. Its radiate noise is 50dB in the direction of 90°~120°at blade

frequency.

Key words: Centrifugal pump, Pressure Fluctuation, Flow exciting

force, Vibration acceleration, Flow-induced noise

摘要

Abstract

第一章绪论 .................................................................................................................... 1

1.1 研究背景及意义 ................................................................................................ 1

1.2 离心泵流动激励诱导噪声与振动的研究现状 ................................................ 2

1.2.1 实验研究 .................................................................................................. 2

1.2.2 数值研究 .................................................................................................. 3

1.3 本文主要研究内容 ............................................................................................ 5

第二章数值模拟方法及离心泵网格无关性验证 ........................................................ 7

2.1 数值模拟方法 .................................................................................................... 7

2.1.1 流场数值计算方法 .................................................................................. 7

2.1.2 声场数值计算方法 .................................................................................. 9

2.2 计算模型介绍 ................................................................................................... 11

2.3 计算模型网格的划分 ...................................................................................... 14

2.4 网格无关性的验证 .......................................................................................... 16

2.5 本章小结 .......................................................................................................... 20

第三章叶片数对离心泵流场及声场的影响 .............................................................. 21

3.1 叶片数对离心泵定常流场的影响 .................................................................. 21

3.1.1 离心泵水力性能对比分析 .................................................................... 21

3.1.2 离心泵定常流场特性对比分析 ............................................................ 22

3.2 叶片数对离心泵非定常流场的影响 .............................................................. 26

3.2.1 蜗室内表面的压强分布 ......................................................................... 26

3.2.2 叶片数对叶轮流动激励力的影响 ........................................................ 29

3.2.3 叶片数对不同时刻叶轮涡量的影响 ..................................................... 31

3.3 叶片数对离心泵流动诱导噪声的影响 .......................................................... 33

3.4 本章小结 .......................................................................................................... 38

第四章 RT/D2对离心泵流场及声场的影响 ................................................................ 39

4.1 RT/D2对离心泵定常流场的影响 ..................................................................... 39

4.2 RT/D2对离心泵非定常流场影响 ..................................................................... 41

4.2.1 蜗室内表面的压强分布 ........................................................................ 41

4.2.2 RT/D2对叶轮流动激励力的影响 ........................................................... 43

4.2.3 RT/D2对不同时刻叶轮涡量的影响 ....................................................... 45

4.3 RT/D2对离心泵振动噪声的影响 ..................................................................... 47

4.4 本章小结 .......................................................................................................... 51

第五章叶片前缘位置对离心泵流场及声场的影响 .................................................. 52

5.1 叶片前缘位置对离心泵定常流场的影响 ...................................................... 52

5.2 叶片前缘位置对离心泵非定常流场的影响 .................................................. 55

5.2.1 蜗室内表面压强分布 ............................................................................ 55

5.2.2 叶片前缘位置对叶轮流动激励力的影响 ............................................ 57

5.2.3 叶片前缘位置对不同时刻叶轮涡量的影响 ........................................ 59

5.3 叶片前缘位置对离心泵流动诱导噪声的影响 .............................................. 61

5.4 本章小结 .......................................................................................................... 64

第六章结论与展望 ...................................................................................................... 66

6.1 研究工作总结 .................................................................................................. 66

6.2 研究展望 .......................................................................................................... 66

参考文献 ........................................................................................................................ 68

在读期间公开发表论文和承担科研项目及取得成果 ................................................ 72

致谢 ................................................................................................................................ 73

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摘要：

摘要离心泵在运行的过程当中，由于水泵的机械结构以及内部的流体运动均能使激励力改变，从而产生振动和噪声，对周围环境造成影响。按照噪声产生机理可以分为机械结构振动噪声和流体激励产生的噪声。其中机械噪声主要由水泵叶轮及轴的不对称和不对中引起的；而流体激励产生的噪声则与离心泵内非定常流动引起的叶片表面、蜗室内表面的压强脉动及泵内涡流密切相关。叶轮作为离心泵的核心工作部件，其叶片数及叶轮子午流道形状对离心泵的性能及非定常流场脉动有着重要影响，从而影响离心泵的流动激励及其诱导的噪声。本文基于混合数值模拟方法研究上述因素对离心泵内流动激励力与噪声的影响。混合数值模拟方法是目前进行声场预测的常用方法，该方法忽...

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