Application Of Electrical Resistance Tomography System And Cross-correlation Technique In Two-phase Flows Measurement

Two-phase flow exists widely in nature and industrial processes. To measuretwo-phase flow, researchers around the world introduced many technologies into thisfield, in which ERT (Electrical Resistance Tomography) technique andcross-correlation measurement both are paid more attention. In this paper, ERT systemand cross-correlation measurement method of two-phase flows are mainly presented.The specific work that the author has finished in this paper is as follows:1. The system structures of several generations of ERT prototypes developed by thesubject group and the difference between them are presented. The progress of thesine wave signal generator, the improvement of VCCS and the evolution ofdemodulation method are introduced.2. The characteristic of improved-ERT system using DSP as the system core isintroduced. The design of CPLD module in novel ERT system is carried out. Thedesign procedure and the performance index of this module are introduced. Thismodule can implement the logical functions required by system, which is provedby the debugging results.3. The structure and characteristics of the dual-plane ERT system for correlationmeasurement are discussed. The slug flow and bubble flow experiments operatedin simulation pipeline using the system are achieved.4. The correlation measurement methods that using variance, mean and square rootof variance-mean quadratic sum extracted from boundary voltage variation aseigenvalue signals is proposed and the physical significance of these parametersin two-phase flow process is explained.5. The measured data of slug flow and bubble flow are processed according to threeeigenvalue-extraction methods proposed, and the processed results are analyzed.The results demonstrate that the uniform results are obtained by correlating thethree eigenvalues. The difference between the correlation velocity and themeasured velocity is small.