Local flow regime analysis in vertical co-current downward two-phase flow

In this work, both global and local flow regimes in two-phase downward flow in a 50.8 mm internal diameter pipe in adiabatic conditions have been identified. The bubble chord length distributions measured simultaneously with three double-sensor conductivity probes have been used along with a self-organized neural network for classification. The flow regime identification results show a reasonable agreement with published models. However, only the local flow regimes measured in the center of the pipe agree with the global ones. The local flow regimes combinations found, corresponding to eight different global flow regime configurations, are analyzed and compared with the combinations obtained for upward flow in a previous work.

► Global and local flow regime maps have been obtained for downward two-phase flow.
► CPDFs of bubble chord lengths used as flow regime indicators and ANNs as classifiers.
► Identification results agree with Usui model [15].
► LFR combinations found in upward and downward flow conditions have been compared.
► LFR combinations allow to identify between Falling Film and Drop Annular flow regimes.