Research On Pipeline Descaling Principles Based On Guided Ultrasonic Waves

Pipeline transportation,as an important way of energy transportation in modern industry,plays an important role in many fields.Removing fouling in time and effectively has been a vexing problem in industrial field for a long time.It's significant in industrial safety production,social and economic efficient and stable development.The application of guided ultrasonic wave in the field of fouling removal not only inherits the advantages of traditional ultrasonic cleaning,such as high efficiency and less damage,but also can remove long-distance and large-scale fouling in pipeline without stopping production.It can remove the fouling just by removing the minimum coating outside the pipeline,which greatly saves time and production cost.In this paper,the mechanism of guided ultrasonic wave for pipeline descaling is studied,and the factors which affect the descaling process are analyzed.An effective descaling method of liquid filled pipeline based on the cavitation effect of leaky ultrasonic guided wave is proposed and validated by experiments.The main work and conclusions are as follows:1.The mechanism of guided ultrasonic wave fouling removal based on the cavitation effect of leaky guided wave was proposed,and the frequency selection criterion based on cavitation acoustic pressure,displacement resonance,fatigue limit and uniformity of fouling removal was proposed too.2.A finite element analysis was used to simulate the propagation and leakage of guided ultrasonic wave in liquid-filled pipeline.According to the frequency selection criterion,the appropriate frequency of sensor was selected to provide guidance for the manufacture of sensor.3.In order to simulate the growth of fouling in an actual pipe,an integrated fouling preparation device was designed,which mainly focused calcium carbonate as the main component,and fouling growth was carried out in the experimental pipeline.4.Based on the results of finite element analysis,the sensor was manufactured and fouling removal experiments were carried out.The micro-structures of the inner wall of the pipeline before and after the experiment were observed under SEM,which proved the effectiveness of the guided ultrasonic wave cavitation effect.The fouling removal power was 60W,and the calcite crystal fouling with a thickness of 22-24 microns could be removed within 20 minutes within a range of at least 1 meter.5.In order to study the effect of ultrasonic high frequency vibration on fouling removal,the vibration scale removal experiment of pipeline without liquid filling was carried out.It was proved that the effect of guided ultrasonic wave cavitation was better than that of only high frequency vibration and cleaning.