Abstract
Deterioration of water-flow regime in a pipeline system has resulted in water-leak accidents due to damage accumulation in pipe materials. Evaluation of water-flow regime in pipeline system is currently in urgent demand. In this study, acoustic emission (AE) method is applied to the evaluation of water-flow regime in an existing PC pipeline, which was inspected and then repaired after water-leak accidents. At three conditions, experiments were conducted. First, a water leak phenomenon was investigated. Secondly, an evaluation of water-drained condition was made in the pipeline. Thirdly, experiments were carried out when the pipeline was filled with water after repairing the water-leak section. AE method was applied to detect signals of water-leak and flow under these conditions. The results show that water-leak in the pipeline system could be quantitatively evaluated by using AE hit activity as well as AE energy. AE hit rate was varied with the situation of the pipeline until the pipeline was filled with water. AE energy showed the same behavior as AE hit rate. When an AE sensor was installed on an air valve, AE energy dropped temporarily as the pipeline was being filled with water. However, when water was filled up to the air valve, the increase in AE energy was confirmed. Thus, it becomes clear that when a pipeline is being filled with water after the repair, the situation of water in the pipeline can be clearly identified through AE monitoring. Discharge evaluation of a damaged pipeline system can be conducted in a short time through AE monitoring.
