Research on liquid pipeline blockage based on quasi-distributed FBG

The blockage of liquid pipelines greatly affects the safe operation of pipelines, while it is rarely discussed in the previous studies. In this paper, the Fiber Bragg Grating (FBG) sensor is used to monitor the blockage state of liquid pipeline system, and the wavelength shift characteristics of FBG under different degrees of front blockage and rear blockage are discussed. The experimental results have shown that the liquid flow velocity is affected when the inner liquid pipeline is blocked, and the wavelength shifts of different FBGs show the significant differences. Specifically speaking, when the pipeline is blocked, the FBG sensor before and after the blockage point will show the opposite wavelength shifts. The FBG center wavelength shows the red-shift when it located before the blockage point, while the blue-shift occurs when it located after the blockage point. The wavelength shift range is closely related to the relative position between the FBG and the blockage point. Besides, the wavelength shift of FBG caused by rear blockage is significantly greater than that of the front blockage. Based on the above results, an effective method to detect the pipeline blockage can be summarized. These research results provide important theoretical support and technical guidance for real-time monitoring of pipeline health status and prevention of pipeline blockage.