ICONE15-10338 FLOW REGIME IDENTIFICATION AND ANALYSIS IN ADIABATIC UPWARD TWO-PHASE FLOW IN AN ANNULUS GEOMETRY

抄録

The main objective of this work is to identify and analyze two-phase flow regimes in adiabatic upward flow conditions in an concentric annulus geometry with an inner diameter of 19.1 mm and an outer diameter of 38.1 mm, at three axial locations (z/D_H: 51.5, 148.8, 229.9). In this regard, both Global Flow Regimes (GFRs) and Local Flow Regimes (LFRs) have been identified. In both cases, neural networks techniques have been used to obtain objective identification results. However, the flow regime indicator will be different depending on the type of flow regime: the cumulative probability distribution function (CPDF) of the area averaged void fraction obtained by impedance meters in the case of GFRs and the CPDF of the bubble chord length measured by a four-sensor conductivity probe in the case of LFRs. The GFRs maps have been compared with those obtained in previous research works and flow regime transitions existing correlations. The LFRs have been identified in five radial locations. The LFRs combinations maps have been compared with the GFRs and those combinations obtained in round pipes.