An Indirect Flow Pattern Identification Method Via Detecting The Inflection Characteristics Of Performance Curves Of The Centrifugal Pump With Experimental Validation

This paper aims at the characteristics and transition mechanism of gas-liquid twophase flow through a rotating centrifugal pump.With the hydraulic performance tests and visualization experiments of the gas-liquid flow inside the rotating impeller,the gas-phase transportation features and flow pattern transition mechanism can be theoretically analyzed.Based on the inflections on H-Q performance curves of the centrifugal pump under gas-liquid two-phase flow,a novel indirect flow pattern recognition method is proposed.The non-linear decline trend of the centrifugal pump performance that is affected by the gas/liquid flow rates or intake gas volumetric fraction(GVF)is studied,from which the two-phase flow pattern maps at varying rotational speeds are obtained.Then,the gas-liquid two-phase flow pattern characteristics and the transition mechanism can be revealed.By CFD simulation and dynamic mode decomposition(DMD),the internal gas distribution of the centrifugal impeller is explained analytically.The effect of different modes on the two-phase flow field is investigated by corresponding cohesive structures of the flow field.Finally,the applicability and accuracy of applying DMD approach to the reconstruction of gas-liquid two-phase flow field within the rotating centrifugal pump can be verified.