Research On Ship Pipeline Leakage Detection Method Based On Bond Graph

Under the background of "Industry 4.0" and "Made in China 2025",ship intelligence has become an inevitable trend in the development of today’s shipping industry,which also puts forward higher requirements for the safety and reliability of ship systems and equipment.Among them,the ship pipeline system is the link of ship equipment,is the key component of the ship’s systems,and most of them are in the harsh working environment of vibration,corrosion,high temperature,and high pressure,leakage accidents often occur,and its good working condition is the guarantee of ship operation safety.Therefore,from the aspect of improving the reliability and safety of the system,it is of great significance to conduct leak detection research on ship pipelines.Focusing on the operating characteristics of the ship pipeline system and combining the physical modeling theory of bonding diagram,this thesis studies the leakage detection method of the ship pipeline system,aiming to improve the accuracy of ship pipeline leakage detection.The main research work of this thesis is as follows:(1)Modeling and analysis of pipeline system characteristics and bonding diagramAccording to the type division and operation characteristics of the ship pipeline system,the factors affecting the modeling accuracy of the pipeline system were analyzed,and the bonding diagram model level of the pipeline system was divided according to different operating conditions and modeling requirements,and the model level of the experimental bench pipeline system was clarified by taking the ship seawater pipeline system as an example.The structure and function of the test bench were analyzed,and the bonding diagram model of the pipeline system of the test bench was established by combining the construction rules of the bonding diagram model of the pipeline system,and the accuracy of the bonding diagram model was verified in the simulation environment.(2)Interval adaptive threshold constructionFirstly,by analyzing the structural characteristics and energy transfer laws of the pipeline system,the dynamic characteristics of the pipeline are mapped in the bonding diagram model,so as to derive the analytical redundancy relationship.Secondly,considering the objective existence of model parameter uncertainty,the uncertainty bonding diagram model of the experimental bench system is established by linear fractional transformation.Finally,combined with the interval mathematical analysis method,the interval analytical redundancy relationship of the system is derived on the basis of the uncertainty system bonding diagram,and then the interval adaptive threshold is derived,and the interval adaptive threshold can effectively avoid the threshold interval expansion problem when the uncertainty interval is asymmetric.(3)Experimental research on leakage detection of ship pipelinesBy setting multiple groups of leakage percentages at the same pipeline position,the accuracy of adaptive threshold and interval adaptive threshold leakage detection under leakage with different valve openings is verified,and the residual response results under experimental conditions are compared,when the uncertainty interval of the parameter is asymmetric,the experimental results show that when the uncertainty interval of the parameter is asymmetric,the interval adaptive threshold can accurately capture the occurrence of more sensitive faults,which can effectively avoid the problem of missed diagnosis and improve the accuracy of leakage detection.