A Half-Ring Conductance Probe For Measuring Phase Volume Fraction Of Two Phase Flow

Two-phase flow dynamics are highly complex, and the accurate measurement and nonlinear dynamics analysis of two-phase flow are increasingly dependent on high resolution signals. The study of high resolution sensor may lead to a deeper insight in two-phase flow dynamics. In the project, the research object is a half-ring conductance probe for measuring phase volume fraction of two phase flow. To conduct a systematic research, first of all, the geometry structure optimization was finished using the ANSYS finite element analysis. Second, the size of test ball in the model was changed considering the different size of oil bubbles in two-phase flow, and the optimal structure of the sensor was given based on the results. Third, a comparative analysis was conducted between sensors with guard electrodes and without electrodes. The results showed that, the sensor got best performance when the size of test ball was in accordance with the height of the electrodes. Following was the water-gas two-phase flow dynamic experiment and oil-water two-phase flow dynamic experiment in vertical upward channel. It is found that the spatial resolution was improved through the structure optimization.Then an improved visibility graph method was proposed, i.e., limited penetrable visibility graph, for establishing complex network from time series. Through evaluating the degree distributions of three visibility algorithms (visibility graph, horizontal visibility graph, limited penetrable visibility graph), it was found that the horizontal visibility graph can not distinguish signals from periodic, fractal, and chaotic systems; For fractal signal, the degree distributions obtained from visibility graph and limited penetrable visibility all can be well fitted with a power-law (scale-free distribution), but the anti-noise ability are not good; For periodic and chaotic signals, the limited penetrable visibility graph shows better anti-noise ability than visibility graph. In this regard, the limited penetrable visibility graph was used to extract the network degree distribution parameters from conductance fluctuating signals measured from gas-water two-phase flow and oil-gas-water three-phase flow test. The results indicate that combination parameters of network degree distribution can be used to classify the typical phase flow patterns.