Study on Leakage Acoustic Signal in Natural Gas Pipeline

The leakage is a serious threat to safety in natural gas transportation pipeline system. When the leakage is happening, the acoustic signal is generated by high-speed jet flow from inter pipelines. Leakage acoustic signal propagates within pipelines, and it can be collected by sensors. Leakage can be detected and located by leakage acoustic signal. The mechanisms of leakage acoustic signal is considerably complex, meanwhile, collecting signal includes much noise, which reduces the accuracy of leakage identification and location. This paper builds a numerical simulation model and analyzes frequency characteristics of leak acoustic signal by CFD (computational fluid dynamics) software. Calculation results of typical chaotic characteristic parameters demonstrate that leakage acoustic signals have chaos. Linear noise reduction methods are not suitable to leakage acoustic signal. Compared to noise reduction effect of wavelet packing and local projection, the latter method can effectively separate noise components and remain high frequency contents. Indoor simulation experimental results indicate that local projection method is suitable for leakage acoustic series noise reduction.