Identification of slug flow in underwater compressed gas energy storage pipeline using pressure signals

Underwater compressed gas energy storage (UWCGES) is a promising marine energy storage technology. In UWCGES systems, the gas transmission pipeline is an important link that connects the upstream gas generation station and downstream gas storage accumulators. Liquid accumulation is generally inevitable in deep-water pipelines. Slug flow tends to emerge with the increasing liquid accumulation in pipelines. This will seriously threaten the efficiency and operating safety of the whole system. Therefore, the effective identification of slug flow in pipelines is an important approach to ensure the normal operation of the UWCGES system. In this study, experiments and simulations are conducted to identify the slug flow in pipelines. The pressure signal on the test pipe and the visual image of the flow pattern in the pipe are analyzed. The multiphase flow simulation software OLGA is used for simulating the experimental pipeline. The mapping relationship between the pressure signal at the inlet of the gas pipeline and the slug flow is obtained. Then, the identification of slug flow by measuring the pressure signal in a single upstream point is realized. Based on this proven method, various deployments of pipelines in UWCGES systems are also simulated, therefore, the effectiveness of the proposed method is further confirmed. The research results can be used for remote monitoring and identification of slug flow in the actual UWCGES systems.