基于主动声学的管道球形内检测器示踪定位方法

Tracing and localization method of spherical inner detector for pipelines based on active acoustics

针对球形内检测器示踪定位难题,提出了一种由内检测器主动发声、在管道外壁远距离实时侦听导波脉冲从而计算内检测器与监测点距离的方法。在分析了该方法定位原理的基础上,通过有限元仿真和实验明确了其实施要点,证明了其有效性。研究表明:内检测器的聚氨酯减振层会严重抑制声波发射,在聚氨酯上开孔使铝球壳与水接触,可以保证足够大的发声强度;快慢两种模态的导波均有明确的起始特征和稳定的传播速度,可用于计算导波传播距离并对内检测器进行定位;但慢波幅值远远大于快波幅值,实际应用时应该使用慢波。最后在Φ219 mm充水钢管中开展了声速测量实验和内检测器定位实验,实验中测得的时延具有极好的重复性,极差不超过80μs,同时实验证明该方法能够实时定位内检测器并监视其远离和靠近监测点的过程。

Aiming at the difficulty of tracing and localization of spherical inner detector, this paper proposes a method of calculating the distance between the detector and the monitoring points through actively emitting sound with the detector and remotely listening to the guided wave pulses in real time on the outer surface of the pipeline. Based on analyzing the localization principle, the implementation key points are clarified and the effectiveness of this method is demonstrated through finite element simulations and experiments. Study demonstrates that polyurethane vibration-damping layer of the detector can severely suppress the acoustic emission, and opening a hole on the polyurethane and making the aluminum sphere shell contact with water can ensure sufficient emitted sound intensity;the guided waves in both fast and slow modes have clear start characteristics and stable propagation speed, which can be used to calculate the guided wave propagation distance and locate the inner detector. The amplitude of the slow wave is much larger than that of the fast wave and the slow wave should be used in practical applications. Finally, sound velocity measurement experiment and inner detector localization experiment were carried out in a Φ219 mm water-filled steel pipe. In the experiments the measured delay has excellent repeatability, its range is not more than 80 μs. The experiments also demonstrate that the method can locate the spherical inner detector in real time and monitor the process of departing from and approaching to the monitoring point.