To analyze the transient characteristics of the severe slugging in piping systems, an inclined pipelinevertical piping system was chosen as a modeling object, and a onedimensional numerical model was proposed to simulate the gasliquid twophase severe slugging. According to the stratified flow and the separated phase theories and based on this theoretical model, the four stagesof the severe slugging—slug formation, slug production, blowout and liquid fallback were modelled respectively. The relative error of the model between the calculated results and the experimental data in published papers is less than 10%, which validates the efficacy of the theoretical model. On this basis, the numerical simulation on the severe slugging phenomenon was conducted, and then the influence of the gasliquid inflow superficial velocities on the transient characteristics of the severe slugging was analyzed. The results show that the severe slugging phenomenon is obviously periodical in the inclined pipelinevertical piping system. With the increase of the gas superficial velocity, the period of the severe slugging decreases, while the pressure fluctuation at the bottom of the vertical pipe increases. The research results can be a reference for the system design and vibration prevention of piping systems.
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