| Process tomography(PT) technique is a new technique developed rapidly in recent years, which has great developmental potential and wide industrial application prospect in solving the measurement problem of multiphase flow. It applies Computerized Tomography of medical engineering to multiphase flow measurement, which 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, having many distinct advantages such as low cost, wide application field, simple structure, non-invade and better safety, Electrical Capacitance Tomography(ECT) has being the most popular research direction and the main development in flow imaging technique. There is still a lot of work to be done before practical use of the technique.This dissertation is based on the study of 12-electrode electrical capacitance tomography system for oil-water two-phase measurement. The topics studied are something around data acquisition system for electrical capacitance tomography. The main problems researched in the dissertation and achievements are as follows: The important meaning of multiphase flow measurement to the science research and industry production is briefly explained. Process tomography based on various sensing technique is introduced. It analyzes the current status and developing trend of the future Process tomography. The principle and constitution of electrical capacitance tomography system is analyzed. The problem of capacitance measurement is analyzed. Studying some kinds of capacitance measurement circuit and methods of stray capacitance elimination, a practical circuit is given. A DSP based data acquisition system of ECT has been develop and the main software has been designed. Two kind of means of communication, which adopts Universal Aerial Bus(USB) and Controller Area Network(CAN) Bus methods, and data acquisition and image reconstruction based on DSP are analyzed. |
PDF Full Text Request