A Dual-modal Tomography System For Oil/Water Two Phase Flow

Electrical Tomography (ET) is a new measurement technique based on the theoryof Electric-magnetic field. Due to the advantages of non-radiant, non-intrusive, rapidresponse and low cost, ET has the attractive developing potential in the field ofindustrial application and clinical diagnosis.Electrical capacitance tomography and electrical resistance tomography are thetwo most developed ET methods nowadays. ERT is suitable to measure the two-phaseflow in which conductive medium is taken as the continuous phase, while ECT issuitable to measure the two-phase flow in which non-conducting medium is taken asthe continuous phase. In order to broaden the measurement range, generally combingthe both ECT and ERT modalities to form an ECT/ERT dual-modal system is used.Therefore, this paper presents a novel unified sensor which can operate in both ECTand ERT modality and a series of experiments for oil-water two phase flowmeasurement are studied based on this dual-modal sensor with the inner electrode,.The main work and results in this paper are as follows:1. Based on the analysis software COMSOL with MATLAB, the numericalsimulations and the optimum design of3-dimensional dual-mode system arestudied. Then, a novel unified dual-modal sensor with the inner electrode isbuilt in this paper.2. This paper analyzes the model of motivation and measurement inECT and ERT system and their hardware circuit, especially pay attention tothe C/V and R/V measurement circuit. Then, a unified hardwaremeasurement system is achieved.3. Combined with the designed hardware circuit, A novel16-electrodedigitized dual-mode system based on FPGA and DSP is designed andimplemented.Then, the modular system programming design is constructed.4. A series of experiments including the research on the measurement range ofECT are studied based on this dual-modal system. The experiments showthat the ECT system can measure the media of high dielectric permittivityand also can be used to measure the media with weak conductive ability. The experiments about oil-water two phase flow show that this dual-modalsystem can operate stably, flexibly, and expand the measurement range.At the end of this paper, some ideas to improve the dual-modal system arepresented.