Research On The Gas Leaking Real Time Detection And Location Of The Pressure Vessel

With the application of gas pressure vessel and high pressure gas transmission pipeline becoming more widespread,meanwhile,some specific application environment(like in-orbit spacecraft operation)occurs,the pressure system stably and safely operated under the high pressure has become the focus of increasing concern.While,gas leakage is one of the main and the fatal factors to threaten its safe operation.When the high pressure vessel leaks due to its own defects or external force factor(such as impact,corrosion),the structure will be damaged and might cause great financial losses.When severe,it could threaten people’s lives and properties.Thus,how to fast and accurate locate the leakage source of pressure vessel has a great and practical meaning.Generally,the pressure vessel leakage can be divided into two types,which are accident leakage and continue leakage.The existing mature real time locating technique is used to locate the accident signal(such as AE signal).In practical,it has been applied to locate impact point,structure breaking point,and the location of the corrosion,etc.But those methods cannot directly estimate the status of the vessel leakage(like whether the system has been leaked,the size of the leaking hole,etc),and cannot locate the existing leakage source either.For the continue signal source which is generated by the existing leakage,the current locating technique is generally needed the manual intervention,and the detecting range is small and time is long,it cannot real time detect the huge vessel.Thus both of these methods don’t meet the requirement of the real time detecting and locating.Therefore,this paper researches on the propagation rule of the acoustic wave(generated by the leakage source)propagates in the vessel skin,and presents a real time leakage detecting and locating technique which based on the acoustic signal.A huge number of relative experiments have been done,then many great research achievements have been obtained.The main content can be summarized as below:(1)The generating mechanism and propagation characteristic of acoustic wave generated by the leakage source have been researched,the experimental platform of the simulated leakage has been set up,and the time-space domain characteristic of leakage signal has been analyzed.Meanwhile,the time domain propagation diagram of the acoustic wave propagates in the vessel skin has been obtained through the Finite Element simulation and the Laser Doppler Vibrometer experiment platform.Besides,under different structures and different medium conditions,the propagation characteristic has been researched.(2)For normal structure of the vessel skin,a method of gas leakage source real time locating based on the ultrasonic signal time-space domain correlation has been proposed.Through introducing the dispersion and multiple modes characteristic when the ultrasonic guided-wave is propagating,the correlation level between time-space domain of the collected signal in a small range relative to leakage source position in the vessel wall are derived.Besides,the leakage source real time accurate locating is also accomplished.(3)The stiffener structure has a strong impact on the ultrasonic propagation.The mathematical model of the influence of the specific stiffener structure to the leakage signal time-frequency domain has been established.Based on the analysis of the acoustic wave characteristics with the stiffener structure,the expression of the relationaship between the correlation level of the time-space domain and leakage source location has been derived.Moreover,it achieves the real time accurate locating of gas leakage source under this structure.(4)For the practical application,the software system has been developed independently to analyze the experimental data,and the validity of the method has been verified by a large number of experiments.