【作者】 周建会；

【导师】 韩焱；

【作者基本信息】 中北大学 ， 信号与信息处理， 2011， 硕士

【摘要】 随着工业技术的不断发展,两相/多相流检测需求不断增加,高精度实时的多相流参数检测一直是工程和科研领域尚未有效解决的问题。借助电阻层析成像(ERT)技术可以完成以导电介质为连续相的多相流内部参数可视化测量。目前,ERT技术中检测精度和实时性之间的矛盾,是影响该技术工业化应用的主要原因。本文从ERT技术基本原理出发,研究高精度实时ERT测量系统,以满足实际工业应用需求。首先,本文在总结目前电阻层析成像国内外研究现状的基础上,介绍了本课题的研究背景、意义、基本思想和论文的章节安排。其次,在分析电阻层析成像原理、影响系统测量精度和实时性的各方面因素基础上,从硬件和软件设计两个方面详细介绍了电阻成像实时测量系统的基本思路与实现途径。系统采用单电极双极性脉冲电流激励模式设计16电极的电阻层析成像系统,提出采用微控器直接控制高速高精度DAC芯片产生系统激励信号的设计方法,该方法可节省传统的数据同步采集检测模块,简化系统设计。此外,采用程控放大电路和高精度数据采集电路完成系统数据调理与采集,采用串口模式进行实时数据传输。基于Labwindows/CVI开发环境设计了包含串口通信、有限元生成、数据实时成像和测量等功能的上位机处理平台。最后,给出了系统性能测试结果和进一步改进的方向。从传感器形状、数据采集重复精度和实时成像效果等方面测试了系统实时性与精度。测试结果表明,采用DAC芯片产生激励信号的方法有利于简化系统设计;设计的电阻层析成像系统在满足信号激励、数据采集和软件成像的实时性基础上,测量和成像精度均达到了课题要求。更多还原

【Abstract】 With the continuous development of industrial technology, the demand for measuring the two-phase/multiphase flow is increasing, but high precision and real-time parameter measurement of multiphase flow has not been resolved effectively in engineering and scientific fields yet. By using the electrical resistance tomography (ERT) technology we can measure the internal parameters of the multiphase flow which has conductive medium as the continuous phase. At present, the main reason for affecting the industrial application of the ERT system is the contradiction of the real-time and nicety in detecting. To meet the needs of the actual industrial applications, we analyze real-time and high precision ERT measurement based on the basic principle of the ERT system.Firstly, we introduce the research background, research meaning, basic idea of this subject based on the contents and main results of the ERT research.Secondly, on the basis of analysising on ERT imaging principle, the various factors which influencing the accuracy and real-time, we introduce in detail the basic thoughts and the realize way of the real-time ERT measurement system from both hardware and software design. We use the excitation model of single electrode bi-directional pulse current to design the 16 electrodes ERT system. Under the control of microcontroller, using the DAC chip to generate the excitation source, the design can be simplified and the control module for synchronous data sampling can be not needed. Furthermore we use programmable amplifying circuit and high-precision data acquisition circuit to complete the signal processing and data acquisition, and use the serial mode to transmit the data in real-time. Based on the development environment of the Labwindows/CVI, we design the software processing platform which contains the function of serial communication, FEM mesh generation, the real-time data imaging and measurement.Finally, the performance test results and the further development trends are be offered. Based on the experiment of the sensor shape, the repeat precision of the data acquisition and the effect of real-time imaging, we test the real time and accuracy of the system. The test result indicates that by using the DAC chip to generate excitation signal, the ERT system can be simplied. On the basis of satisfying the real-time of signal excitation, data acquisition and software imaging, the designed system can reach the requirement of the subject in precision of imaging and measurement.更多还原