管道泄漏检测的主动式压力波激发膜片特性研究

Research on the Diaphragm Characteristics of the Active Pressure Wave Excitation for Pipeline Leak Detection

设计了主动式压力波发生器,利用压缩空气冲击膜片可以在管道中激发幅值和波形稳定的压力波,从而用于主动式压力波泄漏检测。文章通过实验探究了膜片种类、厚度及预变形对压力波激发特性的影响。实验结果表明,线弹性材料膜片在回弹时会产生很强的负压波,且当进气时间为80 ms及100 ms时,其压力波幅值远低于非线弹性的橡胶膜片;当进气时间为100 ms时,用不同种类橡胶膜片激发的压力波幅值仅相差20 kPa。橡胶膜片厚度对压力波幅值的影响较小,但增加膜片厚度可以避免水侧和气侧压力曲线发生分离。膜片施加预变形可以略微提高压力波幅值,同时使水侧和气侧压力曲线不会分离。因此,压力波激发应当选用橡胶作为膜片材料,适当提高膜片厚度且施加预变形。

In this paper,an active pressure wave generator is designed for leak detection,which can generate pressure waves by using compressed air to impacting the diaphragm.The effects of diaphragm type,thickness and pre-deformation on the excitation characteristics of pressure waves are investigated through experiments.The experimental results show that the linear elastic diaphragm will produce a strong negative pressure wave,and its amplitude is much lower than that of the rubber diaphragm.When the inflation time is 100 ms,the amplitude of pressure wave generated by different kinds of rubber diaphragms has a litter difference(20 kPa).The thickness of rubber diaphragm has little influence on the amplitude of pressure wave,but increasing the thickness of rubber diaphragm can avoid the separation of pressure curve.The pre-deformation can slightly increase the amplitude of the pressure wave.Therefore,the performance of pressure wave excitation can be effectively improved by using rubber diaphragm,appropriately increasing the thickness of the diaphragm and applying pre-deformation.