Negative pressure wave monitoring based leak detection method of multipath pipeline network

A negative pressure wave monitoring based leak detection method of a multipath pipeline network, wherein the method includes following steps:

• Step 1):
• analyzing a propagation velocity of a negative pressure wave in a single straight pipeline to obtain a calculated result of a sound velocity in a thin-walled pipe, the propagation velocity is calculated as below:
• a
• =
• K
• /
• ρ
• 1
• +
• K
• ⁢
• D
• E
• ⁢
• δ
• ⁢
• C
• 1
• ,
• (
• 1
• )
• wherein, a is the propagation velocity, K is an elastic coefficient of liquid in Pa;
• ρ is a density of the liquid in kg/m3;
• δ is a wall thickness of a pipeline in m;
• D is an inner diameter of the pipeline in m;
• E is elastic modulus of a pipe, and is about 2.0×1011 Pa for a steel pipe;
• and C1 is a constraint coefficient of the pipe, which depends on constraint conditions of the pipe, and wherein the calculated result is used for calculating a negative pressure wave propagation time;
• Step 2):
• disposing a plurality of pressure sensors at positions of the pipeline, and marking the pressure sensors at known disposing positions on a pipeline network map;
• Step 3):
• linearly interpolating position coordinates of nodes in the pipeline network to extend pipeline network information;
• resolving the time that a negative pressure wave signal generated by a leak propagates to each remote treatment units (RTUs) at each position in the pipeline network in sequence, to form a data column, and thus establishing a time delay standard library;
• and
• Step 4):
• simulating a leak situation, detecting a pipeline pressure waveform by using the RTUs in a current network, and after calculating a difference between the measured arrival time of the negative pressure wave at each position and the time delay standard library as a reference, determining a point corresponding to the data column closest to a measured propagation time delay in the time delay standard library as a leak point, and outputting the position of the leak point.