Design Of DSP-based ERT System And Its Application Research For Parameter Measurement Of Two-phase Flows

In recent years, the electrical resistance tomography (ERT) technology has gradually put into industrial pratical research, and there are many successful applications in geological exploration, industrial process and environmental monitoring, etc. In the actual industrial environment, the gas/liquid two-phase flow is of high flowing speed. However, the current imaging speed of electrical resistance tomography system is very difficult to meet the industrial speed requirements. Therefore, in order to solve this problem, the thesis has untertaken an in-depth research and detailed experiments.Starting from improving the real-time of data acquisition circuit, this thesis focuses on the design of the experimental ERT system. Ultimately, this thesis completes the ERT imaging system platform research based on DSP and the primary measurement research of gas/liquid two-phase flow.The main study work is as follows:(1) Untertaken a detailed study of the principles and development of the process tomoagraphy technology and made a comparison of the characteristics of current technologies. Then, the thesis had a summary of the technical difficulties in realizing the system.(2) Based on a full understanding of the thought of hardware system design, and through analysis and comparison, the author modified the signal acquisition circuit. As a result, this method shortened the response time to signal. Futhermore, the research established a set of real-time, stable hardware platform of ERT system. Now, the system is designed to work in 20KHz incentive signal.(3) Fully undersood the related knowledge of DSP embedded system, including the DSP hardware, CCS software. Develop DSP software platform of ERT system, the research has realized the initialization of peripheral devices, control of the signal acquisition process, real-time reconstruct imagines as well as control of the USB device to send images.(4) Analyzed the traditional image reconstruction algorithm and made improvements. By applying a kind of algorithm based on off-line iterative to ERT system, and through experimental comparison, this algorithm has been verified to be a good comprehensive performance.(5) Designed and produced the gas/liquid two phase flow experimental equipment, and carried out experiments to bubbly flow. Finally, the research verified the feasibility of monitoring bubble behavior using ERT system.