用于气液两相流参数测量的新型非接触式电阻抗传感器

发布时间：2018-03-23 00:20

本文选题：电阻抗测量　切入点：气液两相流　出处：《浙江大学》2017年硕士论文　论文类型：学位论文

【摘要】：气液两相流在自然界以及石油、化工、能源等工业领域广泛存在,其参数测量具有重要的意义但同时也面临极大的困难。基于气液两相流等效电导特性的两相流参数测量方法以其结构简单,成本低,响应快且安全性高等优点而备受关注。然而传统的电导检测多采用接触式的测量方法,存在电极极化以及电化学腐蚀等问题。近年来提出的电容耦合式非接触电导检测技术(C4D)提供了一种有效的解决途径,但是,现有的C4D传感器在气液两相流测量应用中仅以获得待测流体等效电导信息为目的,即仅获得和利用流体电阻抗信息的实部或幅值,对于气液两相流而言,则测量信息的获取和利用不完整。本文以获取气液两相流电阻抗信息为目的,在C4D技术的基础上,研发了一种新型的非接触式电阻抗传感器,并将其应用于气液两相流流型辨识和相含率测量。本文主要内容和贡献如下:(1)提出了一种基于径向两电极传感器的非接触式流体电阻抗测量方法,用于获取气液两相流截面电阻抗信息。该方法为消除耦合电容的影响,准确获取流体电阻抗信息,引入串联电感,利用其产生的感抗来消除测量电路中耦合电容产生的容抗。同时,利用相敏解调技术实现待测流体电阻抗实部和虚部信息的测量,从而获得完整的电阻抗信息。(2)对上述电阻抗测量方法中应用的新型径向两电极结构电阻抗传感器几何尺寸参数进行了优化设计。仿真和实验结果表明当电极长度为管道外径1.5倍,电极张角为120°时传感器灵敏度最优。(3)基于所获得的优化设计参数研制了新型非接触电阻抗传感器,并分别进行了模拟阻抗测量实验和实际电导测量实验以验证其性能。实验结果表明,模拟阻抗测量的实验以及不同浓度的KC1溶液下的电导测量实验相对误差均不超过5%,所提出的非接触电阻抗测量方法是有效的,研发的电阻抗传感器是成功的。(4)将所研制的新型非接触式电阻抗传感器应用于气液两相流流型辨识,结合K-means聚类算法提出了气液两相流流型辨识的新方法。分别在三种不同内径(3.5 mm,5.5 mm和8.2 mm)的管道内进行了动态实验,实验结果表明所提出的流型辨识方法是有效的,实验结果同时表明,对比单独利用实部、虚部或幅值信息的辨识结果,利用完整电阻抗信息的辨识准确度有明显提高。由所获得的电阻抗实部、虚部和幅值信号的均值、方差和傅立叶变换得到的频率特征构成特征向量,并利用K-means聚类算法实现四种典型流型(环状流、泡状流、段塞流、层状流)的流型辨识准确率分别高于88%、97%、90%、90%。(5)将所研制的新型非接触式电阻抗传感器初步应用于气液两相流相含率的测量研究,并提出了一种气液两相流相含率测量新方法。该方法建立了不同流型下的相含率测量模型,根据流型辨识的结果,选择相应的相含率测量模型实现相含率的测量。在两个不同管径(5.5 mm和8.2 mm)下进行了相含率测量实验,实验结果表明,所提出的气液两相流相含率测量方法是有效的,测量的绝对误差不超过7%,对比单独利用实部、虚部或幅值信息测量误差有所降低。综上所述,本文所提出的非接触式电阻抗测量方法是可行的,基于该方法研制的电阻抗测量传感器可同时获得两相流体完整的电阻抗信息(包括实部,虚部和幅值),在气液两相流典型流型的流型辨识中取得了较好的效果并成功应用于相含率的测量,为气液两相流参数测量提供了借鉴。
[Abstract]:The gas-liquid two-phase flow in nature, petroleum, chemical, energy and other industries widely exist, the parameter measurement has important significance but also faces great difficulties. The parameters of two-phase equivalent conductance characteristics of gas-liquid two-phase flow measurement method based on its simple structure, low cost, quick response and high security concern. However, the traditional conductivity detection using contact measurement method, existence of electrode polarization and electrochemical corrosion problems. Contactless conductivity detection technology capacitive proposed in recent years (C4D) provides a way to solve effectively, however, the existing C4D sensors in the measurement of gas-liquid two-phase flow in the application only to get to the measured fluid equivalent conductance information for the purpose, is the only access to and use of fluid resistance information of the real or the amplitude for gas-liquid two-phase flow, obtaining measurement information and the use of Complete. This paper for gas-liquid two-phase flow electrical impedance information for the purpose, based on the C4D technology, developed a new anti non-contact resistance sensor and its application in gas-liquid two-phase flow pattern identification and phase holdup measurement. The main contents and contributions of this paper are as follows: (1) a resistance measurement non contact type fluid resistance two radial electrode sensor is presented based on the gas-liquid two-phase flow is used to obtain the impedance information section. The method to eliminate the influence of the coupling capacitor, to obtain accurate fluid resistance information, the introduction of the series inductance capacitance coupled to eliminate the capacitance in the measurement circuit using the inductance. At the same time, the use of phase sensitive demodulation technique to measure the fluid resistance of the real and imaginary parts of information, so as to obtain complete impedance information. (2) a new radial measurement method in the application of anti resistance two electrode structure The impedance sensor geometry parameters are optimized. The simulation and experimental results show that when the electrode length is 1.5 times the pipe diameter, electrode angle is 120 degrees. The optimal sensitivity of the sensor (3) to optimize the design parameters obtained by the development of a new non contact resistance based on the sensor, and carries out the simulation experiment and impedance measurement the actual conductance measurement experiment to verify its performance. The experimental results show that the conductance measurement experiment simulation of impedance measurement and different concentration of KC1 solution and the relative error was less than 5%, the proposed anti non contact resistance measurement method is effective, development of resistance sensor is successful. (4) a new non contact the research of anti resistance type sensor used in the gas-liquid two-phase flow pattern identification, combined with the K-means clustering algorithm and put forward a new method to identify the flow pattern of gas-liquid two-phase flow in three different. The diameter (3.5 mm, 5.5 mm and 8.2 mm) in pipeline of dynamic experiments, the experimental results show that the proposed method of flow pattern identification is effective. The results also show that compared to separate by the real part, the imaginary part of the identification results or amplitude information, identification information by using the complete anti resistance accuracy is obviously improved by the resistance obtained against the real part, the imaginary part of the signal amplitude and mean frequency, feature variance and Fu Liye transform to form feature vectors, and using K-means clustering algorithm to achieve the four typical flow patterns (annular flow, bubble flow, slug flow, stratified flow) flow regime identification accuracy rate was higher than 88%. 97%, 90%, 90%. (5) measurement of new non contact resistance will be developed by the anti sensor applied in gas-liquid two-phase flow phase holdup, and proposed a gas-liquid two-phase flow phase holdup measurement method. The method is established under different flow patterns Phase holdup measurement model based on the flow pattern identification results, select the phase holdup measurement model for phase holdup measurement accordingly. In two different diameters (5.5 mm and 8.2 mm) for phase holdup measurement experiments, the experimental results show that the proposed two-phase flow phase holdup measurement method to be effective, absolute error of measurement is less than 7%, compared to separate by the real part, the imaginary part of the amplitude information or measurement error is reduced. In summary, non contact resistance the resistance measurement method is feasible, the method developed anti resistance measurement sensor can simultaneously obtain the complete anti phase fluid resistance based on the information (including the real part, the imaginary part and amplitude), flow pattern identification in typical flow regimes of gas-liquid two-phase flow has good effect and is successfully applied to the measurement of phase content, provide a reference for the gas-liquid two-phase flow parameter measurement.

【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212

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