Research On Ultrasonic Phased Array Inspection Method Of Pipeline

Oil and gas pipeline is one of the main means of transportation of oil and natural gas.In-service pipeline is easy to cause corrosion,cracks and other defects due to various reasons,resulting in leakage of transportation materials,reducing transportation efficiency,causing environmental pollution,causing economic losses,even explosion and other hazards.Up to now,there are many methods of pipeline defect detection,such as magnetic flux leakage,ultrasonic and eddy current.The ultrasonic phased array detection technology can control the deflection and focus of ultrasonic beam to detect the defects of the pipeline.The detection results are imaged and displayed on the upper computer,with fast detection speed,high sensitivity and multi-directional detection.According to the ultrasonic phased array pipeline inspection method,the propagation characteristics of the ultrasonic phased array transducer are studied.The one-dimensional linear array is simulated by MATLAB,and the influence of transducer parameters on the sound field is analyzed.Combined with the characteristics of ultrasonic phased array,such as beam deflection and beam focusing,and based on the propagation characteristics of ultrasonic in the pipeline,this paper analyzes the detection method in the pipeline of the ring ultrasonic phased array,analyzes the transducer parameters,scanning mode and detection mode of the ring ultrasonic phased array,and calculates the focusing delay rule of the ring ultrasonic phased array combined with the acoustic path and deflection angle of each element Then.In the experiment,a 128 element ring ultrasonic phased array is used to detect the ?168 pipeline.The method of acoustic beam focusing and arc rotation scanning is used to verify the validity of the delay rule,and analyze the relationship between the number of working elements and the detection effect.In the experiment,defects of ?168 pipeline with corrosion defects are detected,set up different number of working elements and different focal length,analyze the echo signal amplitude of the detection depth of the ring ultrasonic phased array,compare the detection results with the actual defect depth,verify the detection ability of the ring ultrasonic phased array,and analyze the relationship between the number of elements,focal length and detection effect.The results show that the detection effect in the focusing mode is better than that in the unfocused mode when the delay rule is adopted for the ring ultrasonic phased array.With the increase of the number of working elements,the amplitude of echo signal increases first,and then decreases irregularly.For the detection results of pipeline corrosion defects,with the increase of focal length,the detection error shows a trend of decreasing first and then increasing.The number of working elements and focal length in a certain range can get good detection results.It provides a theoretical basis and available scheme for the use of ultrasonic phased array in the internal inspection of pipelines.