Pipeline leakage monitoring experiments based on evaporation‐enhanced FBG temperature sensing technology

Abstract

The water distribution systems in utility tunnel are considered as the lifeline projects. The leakage monitoring of water supply and drainage pipelines is closely related to the overall operation and safety of the utility tunnel. However, conventional pipeline leakage monitoring methods are difficult to realize the monitoring of ordinary temperature liquid and small leakage. Moreover, they also have problems with noise interference, high false alarm rate, and high cost. In order to overcome the shortcomings of the conventional methods, the evaporation-enhanced Fiber Bragg Grating (FBG) temperature sensing (EETS-FBG) method was proposed as a new type of leakage monitoring solution according to the principle of the psychrometer. This method utilizes the evaporative cooling characteristics of water-absorbing porous materials and the FBG temperature sensors to realize leakage monitoring. On the basis of experiments, the feasibility of this method is explored, and the effects of wind speed, liquid temperature, and leakage volume on monitoring results are analyzed. The experimental results show that the EETS-FBG method can monitor the temperature difference of 0.97–8.55°C in the humidity of 51.0–90.8%RH, and the measured values are in good agreement with the theoretical values, which shows that the method has good feasibility. In addition, the measured temperature difference increases with the ambient wind speed, while the leakage volume and water temperature have no obvious effect on the temperature difference, which shows that the method has good reliability and universal applicability. This method has outstanding advantages for normal temperature liquid and small leakage monitoring and is worthy of application and promotion.