【作者】 苗利；

【导师】 刘存；

【作者基本信息】 沈阳工业大学 ， 测试计量技术及仪器， 2003， 硕士

【摘要】 近十几年发展起来的过程层析成象(PT)技术在两相流／多相流流动参数分布状况的测量方面取得了一定的进展，有可能成为解决两相流参数检测的有效手段，具有很大的潜力和广阔的工业应用前景。 电容层析成象技术(ECT)是过程层析成象技术中首先发展起来的，它具有系统成本低，成象速度快，适用范围广，非侵入式等优点，在PT中很有优势。因此，研究了一个交流检测组合式ECT系统。 1．在分析了电容传感器的结构特点之后，对传感器结构尺寸进行仿真计算，建立新型的16极板组合浮置式电容传感器。此传感器的提出使16极板电容传感器的被测电容增加，有利于信号的检测，降低了数据采集的要求。投影数据为104个，有利于提高图象重建的质量。 2．用可编程大规模芯片ispLSI 1032对系统的数字电路进行了集成化设计，达到既简化电路设计又提高系统稳定性、可靠性的目的。 3．开发了ECT系统实验装置。采用交流激励、软件实时补偿的方法提高了系统的稳定性。 4．数据采集系统采用锁相技术、同步检波的原理，降低了整个系统的成本，提高了灵敏度，并使得载波信号与调制信号完全达到同步。PCL-812PG采集卡的使用缩短了系统的开发时间，提高了系统的可靠性。 5．采用Visual Basic为编程语言对数据进行处理、发送与存储，使处理的数据能够直观的显示出来。 6．利用实验测得的数据通过线性反投影(LBP)法进行图象重建，进而验证了整个实验装置的可靠性，实现了在线实时测量。 7．最后对整个系统性能指标进行了评估，通过实验数据计算了系统的灵敏度与线性度，达到了预期的效果。更多还原

【Abstract】 Process Tomography (PT) techniques, which has been development rapidly in recent several ten years, have made certain progress in field of measurement of two-phase flow/multiphase flow parameter’s distribution status. It might become a means for two-phase flow measurement and could be widely applied in industry.Electrical Capacitance Tomography (ECT) is one of the techniques, which is firstly developed for PT. It has low-cost, high-speed, robust and non-intrusive. It has more advantages. So an ECT system of AC measurement combined has studied.1. After analyzing the structure and specialty of capacitance sensor, simulating and calculating the sensor’s size. Then construct a new style capacitance sensor with 16 electrodes combined and floated. Its presentation increases the measured capacitances, and benefits for the measured signals and decreases the requirement of data acquisition. 104 projections benefit for improving the quality of imaging reconstruction.2. System’s digital circuits are integrated into ispLSI (in system programmable large scale integrated chips) 1032 so as to simplify design and to develop the stability and reliability of the system.3. The ECT system experimental equipment is developed. The system instability is improved by using AC excite and soft compensation in real time.4. In data acquisition system, The application of phase-locked and synchronous detection reduce the cost of the whole system and improve the sensitivity. Carrier signal and modulation signal achieve entirely synchronous too. The utilization of PCL-812PG acquisition card has make the system’s developmental time less and improved the system’s reliability.5. Visual Basic programmable language is to process, send, and store the data, and then show them out directly.6. By the experimental result and linear back projection (LBP) algorithm to reconstruct the image, and then verify the credibility of the experiment device, realised measuring in time.7. At last, make an evaluation on the system’s capability guideline, calculate itssensitivity and linearity by the experimental data, results shows that it has achieved the demand.更多还原