基于电导法水平管环状流液膜厚度测量系统设计

发布时间：2018-08-13 11:25

【摘要】：水平管气液两相环状流是工程中非常重要和最常见的流型之一,广泛存在于石油、化工、管道运输、核反应堆等工业领域。水平管内气液两相环状流流动中,由于气流速度较高,液膜界面出现波动,伴随着波动的演化不断有液膜以液滴形式被卷吸到气核中;同时伴有液滴不断飞溅沉降回液膜,并引起二次夹带,因而水平管环状流液膜结构及其动态特性表现出很强的随机性、快速性、复杂性。因此,对水平管环状流液膜的深入研究,构建准确可靠的液膜参数测量系统十分重要。液膜厚度是液膜的重要参数,测量液膜厚度十分关键。本文主要内容是基于电导法水平管环状流液膜厚度测量系统的研究,主要工作如下:1.在单区平均液膜厚度预测模型的基础上引入夹带液滴对气核密度变化的影响,并利用该模型在实验室条件下对水平管环状流平均液膜厚度值进行预测。通过预测水平管环状流周向液膜厚度分布理论模型得出周向不对称参数,即平均液膜厚度与底部液膜厚度的关系,进而估算水平管气液两相环状流底部液膜厚度。2.总结液膜厚度实验测量方法,对电学法测量进行研究。采用电学法中的电导法进行传感器设计,设计出同轴圆环传感器。并用COMSOL软件仿真探究,从尺寸和电极大小两个方面优化,确定传感器结构。3.设计并构建基于电导法液膜厚度测量系统,测量系统包括三个部分同轴圆环传感器、基于FPGA的电导测量系统和静态实验测量装置。进行液膜厚度测量静态实验,分析实验结果。
[Abstract]:Horizontal pipe gas-liquid two-phase annular flow is one of the most important and common flow patterns in engineering. It is widely used in the fields of petroleum, chemical industry, pipeline transportation, nuclear reactor and so on. In the gas-liquid two-phase annular flow in a horizontal pipe, due to the high velocity of the gas flow, the interface of the liquid film fluctuates. With the evolution of the fluctuation, the liquid film is continuously absorbed into the gas core in the form of droplets, and the liquid droplets are splashed back into the liquid film. As a result of secondary entrainment, the structure and dynamic characteristics of horizontal tubular annular liquid membrane show strong randomness, rapidity and complexity. Therefore, it is very important to construct an accurate and reliable measurement system of liquid membrane parameters for horizontal tube annular flow film. The thickness of liquid film is an important parameter of liquid film, and it is very important to measure the thickness of liquid film. The main content of this paper is the research of liquid film thickness measurement system based on conductance method for horizontal tube annular flow. The main work is as follows: 1. Based on the single zone average liquid film thickness prediction model, the influence of entrainment droplets on the change of gas core density was introduced, and the average liquid film thickness of horizontal annular flow was predicted under laboratory conditions. Based on the theoretical model of predicting the thickness distribution of circumferential liquid film in annular flow of horizontal tube, the relationship between the average thickness of liquid film and the thickness of bottom liquid film is obtained, and the thickness of liquid film at bottom of gas-liquid two-phase annular flow in horizontal tube is estimated. The experimental measurement method of liquid film thickness was summarized and the electrical method was studied. The sensor is designed by the conductance method and the coaxial ring sensor is designed. The sensor structure. 3. 3 is determined by optimizing the size and electrode size of the sensor by COMSOL software simulation. A measuring system of liquid film thickness based on conductance method is designed and constructed. The measuring system includes three parts of coaxial ring sensor, a conductance measurement system based on FPGA and a static experimental measuring device. The static experiment of measuring the thickness of liquid film was carried out and the experimental results were analyzed.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH71

【相似文献】