Measurement Of Two-phase Flow Based On Cross-section Measurement Technology And V-cone Flow Meter

Two-phase flow widely existes in nature and industry processes. Gas/liquid two-phase flow, as an important part of two-phase flow, plays an important role in industry and daily life. Beacause of the existence of relative movement and variable interfaces between the two phases, the real time paramaters measurement of two-phase flow becomes a difficult issue in the field of engineering and science.A multi-sensor system which is consisted of Cross-section information system, V-cone flow meter, pressure sensor and temperature sensor has been put forward. Mutli-sensor fusion technique is introduced into the research area of multi-phase flow. This technique has been widely used in the field of military and robot but just comes to a start in multi-phase flow measurement. It could provide us with multi-demension data from multiple aspects of time and space, and consequently achieves improved accuracies and more specific inferences that could be achieved by the use of a single sensor.The physics fundamental of cross-section information detecting technique based on resistance information is that different medium has different conductivity. It has the advantages of non-invasion, non-radiation snd so on. V-cone is a new type flow meter which appears in 1980s, with the advatages of small pressure drop, high repeatability, good linear ability, wide measurement scale and so on. It has received more and more attention from the reseachers worldwide. The final regime recognition result is achieved by using the combination rule of D-S evidence theory, and the mean success rate is 90%.The main achievements in this paper are as follows:1. The experiment of gas/liquid two-phase flow in horizontal pipe with multi-sensor system is carried out in the oil/gas/water three-phase flow laboratory of schoole of electrical engeneering and automation in Tianjin University.2. D-S evidence theory is adopted to make the flow regime recognition based on the cross-section measured voltage. Feature extraction is put forward to reduce data dimension, then primary evidence is obtained from the features according to relative rules.3. Due to mass flow rate accuracy varies by V-cone meter with different differential pressure (DP) models under different flow regime, a comparison of typical DP models based on the correct flow regime recognition. The optimum DP model which achieves the smallest experiment error has been used in the corresponding flow regime. The experiment error is droped effectively under this method.4. Time fusion between the data from cross section information system and V-cone flow meter is put forward in the mass flow rate measurement of plug flow. The real-time data of gas plug and liquid plug have been distinguished and put into corresponding DP models which are suitable for them respectively. The mean experiment error is 4%, which is smaller than result of the directly used of DP model.