Research Of Flow Parameters Detection Methods In Gas Solid Two-Phase Flow

With the development of science and technology, gas-solid two-phase flow systems are more and more widely applied in modern industrial and agricultural production. For example, power plant, ferrous metallurgical and fluid bed reactor, their productive process almost involve material pneumatic conveying which belongs to gas-solid two-phase flow systems. The gas-solid two-phase flow parameters'accurate measurement and real-time monitoring are very important for the stable operation of the production process and product quality. Because of gas-solid two-phase flow belongs to the complex flow system, its flow parameter's detection method is a technical difficulty for a long time.This paper selected electrical capacitance tomography technology as an entry point because of there are some technological merit.Such as noncontact; visualization; and so on. The main contributions and works are as follows:Firstly, this thesis made a statistical research on the electrical capacitance tomography technology, also, established the 2-D and 3-D model, and got the capacitance quickly by means of ANSYS software. Compared with the method by MATLAB or VC, the improved method by ANSYS can greatly save the time and reduce the cost of development.Secondly, this paper simulated a typical eight-electrode sensor and analyzed it which is used in ECT system. The experiment gave the sensitivity distribution of this sensor. The paper reconstructioned pipe internal material distribution image using the neural network. The result indicated that the eight-electrodes sensor doesn't have uniform sensitivity field distribution and higher sensitivity, and it brings difficulties to image reconstruction.Lastly, in order to solve the problem mentioned in the preceding part of the paper, the author simulated and analyzed the coaxial capacitance sensor and spiral capacitance sensor. Experiment result indicates that the coaxial capacitance sensor and spiral capacitance sensor have uniform sensitivity field distribution and higher sensitivity. And their capacitance value of this sensor has nothing to do with flow pattern which is only related to solid concentration change. Therefore, capacitance value can reflect solid concentration directly and avoid the step that got the solid concentration by image reconstruction.Based on what is researched above, the coaxial capacitance sensor and spiral capacitance sensor can measure concentration and speed parameters on-line in air/liquid, liquid/liquid two-phase flow combined with cross-correlation technologies and they have a broad application prospect.