Research On Piezoelectric Vibration Sensor For Oil Pipeline Condition Monitoring

Pipeline transportation is widely used in the transportation of oil and gas and other resources.The safety of oil pipeline is related to the safety of national strategic resources.All kinds of safety accidents of pipeline rupture and oil leakage caused by abnormal vibration of oil pipeline,as well as illegal drilling and oil stealing incidents,not only threaten the national economic security,but also cause long-term harm to the surrounding ecological environment.Therefore,it is necessary to monitor the operation status of oil pipeline.This subject comes from the project of Sinopec: "development of piezoelectric and eddy current vibration sensors".Based on the requirements of oil pipeline vibration measurement,this paper designs a piezoelectric vibration sensor for pipeline condition detection,and applies the sensor to the oil pipeline.The genetic algorithm and support vector machine combined algorithm are used to realize the classification of different operation states of the pipeline.This paper first analyzes the working mechanism of piezoelectric vibration sensor,establishes the force transfer model from external vibration to piezoelectric ceramic vibration,the sensing mechanism model of piezoelectric ceramic vibration causing charge on its surface,and the signal conditioning model of charge signal converted into voltage signal for output,which provides model basis and design basis for subsequent vibration sensor body and circuit design.Secondly,the body design of the piezoelectric vibration sensor is completed from the aspects of the sensitive element design,structure design and signal conditioning circuit design.In the part of sensitive element design,the compression structure is used;In the part of structure design,the appropriate mechanical structure and fixed structure are selected to design the structure of the sensor;In the part of signal conditioning circuit,the charge conversion circuit,conditioning amplifier circuit,filter circuit,output amplifier circuit and regulated power supply are designed.Thirdly,for the needs of pipeline state recognition,the piezoelectric vibration sensor is used in the vibration measurement of oil pipeline,and the support vector machine is introduced for the classification of different operation states of pipeline,which lays the method foundation for the subsequent classification of oil pipeline operation states according to the vibration data samples of oil pipeline measured by the vibration sensor.Finally,an experimental system is built to test the linearity,sensitivity,repeatability error,bandwidth and other indicators of the designed piezoelectric vibration sensor.The piezoelectric vibration sensors are arranged at three positions of the oil pipeline to obtain the measurement results under different operation states of the pipeline.The support vector machine is used to train the operation state classification model,and the genetic algorithm is used to optimize the relevant parameters.Finally,the test set is used to test the model.