Experimental investigation of model-based IMC control of severe slugging

Abstract Severe slugging formation has been investigated experimentally in a two-phase flow-loop composed of a downwardly inclined pipe and a vertical riser. In this study, a bifurcation diagram was made to more clearly identify which flow the current system has at each valve opening. A model was made by inputting the dimensions of the flow loop using OLGA, a multiphase flow simulation program, to compare the experimental results. The model-based control logic was constructed by estimating the transfer function utilizing the OLGA model. The estimated transfer function is used to tune the gain of the PI controller, using the method called the Internal Model Control (IMC). Through this method, PI gain can be easily obtained through only one tuning parameter. When the PI controller gain is obtained through the transfer function of the flow loop system, mitigation of severe slugging was achieved while increasing the flow rate than the case with manual choking.