Process tomography technology based on the principle of electrical sensitivity is a new technology for cross-sectional information measurement developed in recent years. Among them, electrical resistance tomography (ERT) is paid attention to by two-phase / multiphase flow researchers due to its advantages of visualization, non-invasive, no radiation, and low cost. The tomographic imaging technology is used to measure the distribution information of the pipeline section, and the image reconstruction method can realize online flow pattern recognition, and can observe the distribution relationship between the two phases, but the accuracy of image reconstruction has a certain degree of accuracy in the flow pattern recognition. influences. On the basis of a lot of previous research work, the ERT technology is used to further process the pipeline boundary measurement data using the principal component analysis method, extracting useful information that can reflect the cross-sectional phase distribution, and applying pattern recognition technology to achieve online flow pattern recognition under experimental conditions . Experimental program According to the requirements of the ERT to identify the two-phase flow pattern research, in the experiment, the air / water two-phase vertical ascending tube flow was used as the research object, and the ERT system prototype was used to collect five typical flow patterns of simulated flow conditions: single-phase flow (water is full Tube), bubbly flow, elastic flow, multi-bubbly flow, and annular flow data analysis and identification. The experimental device is a plastic transparent pipe with a diameter of 100 mm and gas phase models of different shapes and volumes processed with nylon materials. The simulated flow state mentioned here is not the real flow of the medium in the pipeline during the experiment, but when the liquid phase is stationary, the gas model rises at a uniform speed of 0.5m / s. When the gas model flows, the ERT system continues Collect data to get a data array containing cross-section information. Characterizing a flow feature with three consecutive pieces of data can represent the three-dimensional information of the flow pattern to a certain extent, and improve the accuracy of recognition. Experimental results and analysis Collect single-bubble flow, elastic flow, multi-bubble flow, and annular flow data according to the above scheme, and draw a graph in comparison with the unidirectional flow data. The X axis indicates collecting 4 pieces of data, and the first piece is single-phase flow data The other three pieces of data are collected at the same flow pattern at intervals of 25mm; the Y axis represents 208 points per piece of data; the Z axis represents the measured voltage value. The establishment of the sample database must first establish the classification information database, that is, the sample data that characterizes the flow pattern information before the distance discrimination. For each type of stream sample data, the number of samples must be greater than the number of variables it includes. Since each flow pattern collects three pieces of data with an interval of 25 mm, that is, the number of variables included in the sample is 3, which requires that the number of samples for one flow pattern is not less than 3. Find the Euclidean distance between each measurement data and standard single-phase flow data to obtain sample data of different flow patterns. Did you know that children learn basic principles of physics that are an important component of developmental milestones through play? Seesaws are the perfect example of simple levers at work, and they encourage children to work together by rewarding them with a rollicking ride once they establish a successful rhythm. Seesaw Playground,Kids Playground Seesaw ,Seesaw Playground Equipment,Wooden Playground Seesaw Shenyang Golden Childhood playground equipment CO.,LTD , https://www.outdoor-playground.com
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Analysis of data characteristics of different flow types in pipelines