Research On The Gas/solid Two-phase Online Monitor Of Electrical Capacitance Tomography

Two-phase stream (heterogeneous stream) system relates to range in giving birth to a child in industry and agriculture very broad, if gas in reaction device/ strengthens the two-phase stream midstream melt bed oil/ gas, two-phase stream of oil/ water, chemical industry in oil industry.Process topographic imaging technology, a recently appeared novel technique, applies Computerized Tomography of medical engineering to multiphase process measurement. It can measure the parameters of multiphase flow according to the phase distribution image of the cross section of multiphase. Compared with other multiphase flow measurement technologies, it can provide instantaneous microcosmic information of the parts of multiphase;Electrical capacitance tomography (ECT) is a kind of flow tomography techniques that are widely studied. 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. The topics of this dissertation are small capacitance measurement that is a key part in ECT designs and ECT applications, high-speed data acquisition system design .The main works are listed as follows:1. It is pointed out that multi-phase flow parameter detection is very important for research and industry production.2. The principle of the capacitance tomography and structure of the system are analysed and basic characters and statuses in quo are introduced, the small capacitance measuring circuit for ECT based on the charge amplification principle was deeply analyzed;3. Because ECT has strict demand for capacitance measurement, the design of capacitance/voltage converting circuit which is used to measuring capacitance becomes a nodus. Through studying some kinds of capacitance measurement circuit, a practical one is given. The static characteristic indexes are give ninth is dissertation after some experiments have been done; 4. It puts forward and designs a digitalized system of electrical capacitance tomography. The designed system is based on the high speed digital signal processing to provide a new digitalized system of electrical capacitance tomography, which includes the digital filtering and the digital demodulating algorithm on t he basis of the AD536.5. The go along rebuilding an algorithm to several kinds ECT at present in common use image studies in a deepgoing way, the comparatively various algorithmic characteristic of imaging and applicability, analyse the major factor affecting the mass rebuilding an images,Measure, reach thereby the call for designing that by simulating carrying out imaging comparison on different algorithm;6. Have developed the systematic tester of ECT, the static characteristic , sensitiveness , linearity and pragmatism having been in progress to system have done and large amount of experiment , the analysis being in progress , have reached that system being able to satisfy the call for designing demand.