1178. 急拡大を伴う鉛直円管内空気―水系気泡流に対する1次元2流体モデルの適用性

Abstract

Experiment and numerical calculation were made on the multi-dimensional behavior of upward gas-liquid bubbly flow in a vertical pipe with an axisymmetric sudden expansion. The variation of the void fraction distribution in the sudden expansion was measured at the different axial and radial positions using a point-electrode resistivity probe for various gas and liquid flow conditions. Based on the measured void fraction distribution in the sudden expansion, the axial profiles for the phase distribution parameters were evaluated in the sudden expansion. Numerical calculations were carried out to predict the cross-sectional averaged void fractions along the flow direction by using the one-dimensional two-fluid model considering the phase distribution parameter to verify the applicability of the computations. From these results, it concretely pointed out that some multi-dimensional modeling or modifications for numerical simulation would be needed and the distribution parameter was one of the most important parameters for one-dimensional two-fluid model to evaluate accurately the void fraction distriblltions affected by the multi-dimensional channel geometry.