论文总字数：31684字

摘 要

离心泵是指靠叶轮旋转时产生的离心力来输送液体的泵，在工业生产和日常生活中应用极为广泛。随着经济的不断发展，输送单一介质的离心泵已经无法满足生产需求，因此，对两相流泵的研究成为流体机械领域的一大热点。为了研究离心泵吸水管内气液两相流动的特点，本文以离心泵两相流的可视化试验为基础，采用摄像技术对吸水管内的流型进行拍摄，研究了离心泵吸水管内气液两相流动的规律。

本文的主要研究内容和结论如下：

（1）开展了离心泵吸水管内气液两相流动可视化试验，并采用摄像机对离心泵吸水管内的流动进行拍摄，通过观察和比较对吸水管内的流型进行分析。离心泵吸水管内气液两相流型可分为：螺旋泡状流、稳态泡状流、脉动泡状流，螺旋塞状流、稳态塞状流、脉动塞状流，螺旋层状流、稳态层状流、脉动层状流。

（2）对不同工况下所拍摄的流型图片进行分类整理，采用控制变量法，研究了离心泵吸水管内流型变化的影响因素。研究结果表明：影响吸水管内流型的因素主要有液体流量Q_l、气体流量Q_g、泵转速n。其中，液体流量Q_l和气体流量Q_g对流型变化的影响较大，而泵转速n的影响较小，在液体流量较大的工况下，转速对吸水管内流型几乎没有影响。

（3）对不同工况下的气泡大小和数量进行了统计，并通过绘图进行了分析。结果表明：在不同的液体流量工况下，随着气体流量的改变，气泡尺寸和数量的变化规律不同。

（4）采用控制变量法，分析了气泡螺旋长度的影响因素以及螺旋流出现的条件。结果表明：影响气泡螺旋长度的因素主要有液体流量Q_l、气体流量Q_g、泵转速n，在气体流量一定时，转速越高，对应出现螺旋流的液体流量越大。

关键词：离心泵 吸水管 气液两相流 流型 可视化试验

ABSTRACT

Centrifugal pump is a kind of pump that transports liquid through centrifugal force generated by impeller rotation. It is widely used in industrial production and daily life. With the continuous development of the economy, the centrifugal pump that conveyed a single medium has been unable to meet the demand of production. Therefore, the study of two phase flow pump has become a hot spot in the field of fluid machinery. In order to study the characteristics of gas-liquid two phase flow in the suction pipe of a centrifugal pump, based on the visualization test of the two phase flow in centrifugal pump, the flow pattern in the suction pipe was photographed by camera technology and the gas-liquid two phase flow laws in the suction pipe of the centrifugal pump were studied.

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

(1) The visualization test of gas-liquid two phase flow in the suction pipe of a centrifugal pump was carried out, and the flow pattern in the suction pipe of the centrifugal pump was photographed with two cameras. The flow pattern in the suction pipe was obtained through observation, analysis and comparison. The gas-liquid two phase flow patterns in the suction pipe of a centrifugal pump can be divided into spiral bubbly flow, steady bubbly flow, pulsating bubbly flow, spiral plug flow, steady plug flow, pulsating plug flow, spiral stratified flow, steady stratified flow and pulsating stratified flow.

(2) The flow pattern pictures under different working conditions were classified. The influencing factors of flow pattern in the suction pipe of centrifugal pump were studied by using the control variable method. The research results show that the main factors affecting the flow pattern of suction pipe include liquid flow rate Q_l, gas flow rate Q_g and pump speed n. The effect of liquid flow Q_l and gas flow Q_g on the flow pattern is large, and the effect of the pump rotational speed n is small. In the case of large liquid flow rate, the speed has little influence on the flow pattern of the suction pipe and even almost no effect.

(3) The size and number of bubbles under different working conditions were statistically analyzed and plotting was carried out. The results show that, with the change of gas flow, the size and quantity of bubbles are different under different liquid flow conditions.

(4) The factors affecting the spiral length of bubbles and the conditions of spiral flow were analyzed by the control variable method. The results show that the main factors affecting the spiral length of the bubble are liquid flow Q_l, gas flow Q_g and pump speed n. When the gas flow rate is constant, the higher the rotational speed, the greater the liquid flow corresponding to the spiral flow.

KEYWORDS: Centrifugal pump; Suction pipe; Gas-liquid two phase flow; Flow pattern; Visualization test

目 录

摘 要 I

ABSTRACT II

第一章 绪论 1

1.1 气液两相流泵研究的背景和意义 1

1.1.1 研究背景 1

1.1.2 研究意义 2

1.2 气液两相流泵的研究现状和发展趋势 3

1.2.1 研究现状 3

1.2.2 发展趋势 6

第二章 离心泵吸水管内气液两相流试验装置 7

2.1 离心泵试验台 7

2.1.1 试验台的组成 7

2.1.2 试验装置的工作原理 9

2.1.3 试验装置重要仪器简介 10

2.2 模型泵 11

2.2.1 模型泵简介 11

2.2.2 模型泵水力性能分析 12

2.2.3模型泵可拍摄性能分析 13

2.3 本章小结 13

第三章 离心泵吸水管内气液两相流试验内容和方法 14

3.1 试验内容 14

3.1.1 拍摄取样 14

3.1.2 分析流型变化规律 14

3.1.3 气泡螺旋长度的影响因素 15

3.2 试验步骤 15

3.2.1 输送纯水时的试验步骤 15

3.2.2 可视化试验步骤 15

3.2.3 操作中的注意事项 15

3.3 采用的摄像方法 16

3.3.1 摄像机的选择 16

3.3.2 摄像机的拍摄区域和布置 16

3.4 试验误差分析 17

3.4.1 试验仪器带来的误差 17

3.4.2 统计和测量误差 18

3.4.3 减少试验误差的方法 18

3.5 本章小结 19

第四章 离心泵吸水管内气液两相流试验结果与分析 20

4.1 不同工况下吸水管内的流型 20

4.1.1 流型随液体流量Q_l的变化 20

4.1.2 流型随气体流量Q_g的变化 23

4.1.3 流型随泵转速n的变化 27

4.1.4 吸水管内流型图谱 29

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