The Design And Application Of Electrical Capacitance Tomography Technique Systems

Two-phase stream (heterogeneous stream) system is applied broadly in industry and agriculture. Process topographic imaging technology as a recently appeared novel technique just developed from this. Compared with other multiphase flow measurement technologies, it can provide instantaneous microcosmic information of the parts of multiphase.Electrical capacitance tomography (ECT) is a research spot on the flow tomography techniques. ECT is fast, non-invasive, low cost, safe and widely applicable. It has become one of important techniques for two-phase flow parameter measurement. But there are some problems and difficulties in ECT designs and ECT applications. This paper researched a set of high-speed ECT system considering some restrictions such as weak capacitance measurement and the speed of data acquisition. The main works are listed as follows:1. Multi-phase flow parameter detection is very important in scientific research and industry, this paper analyzed its development history and actuality, introduced the characteristics,development actuality and working theory of ECT;2. The paper discusses the structure of ECT system, we also introduced the composing and the structure of ECT sensor, then we optimized the sensor in ECT system;3. We emphasize on the capacitance measurement in system's sensor. Through comparing many kinds of capacitance measurement circuits, we put forward one kind of applied and high-speed capacitance/voltage converting circuit. Experiments indicated that this circuit has a good static characteristic;4. It puts forward the digital project about ECT system, we designed a digital ECT system based on the high-speed DSP processor through AD536 which realized AC/DC voltage conversion;5. We introduced some kinds of ECT rebuilding algorithms which are in use, their characteristics and scopes are also included. We especially analyse the major factor affecting the rebuilding images. We aslo did some cyber- simulation on those rebuilding images algorithms,we finally choose the iterative algorithm by comparison in order to satisfy the system design;6. We made a set of ECT tester and did many experiments on the static characteristic , sensitiveness , linearity and practicability. The results indicate that this ECT system can satisfy the design;...