Effect of rubber washers on leak location for assembled pressurized liquid pipeline based on negative pressure wave method

Leakage in pressurized pipelines is a serious problem in petrochemical plants because it might cause a fire or an explosion. The negative pressure wave (NPW) method is a practical method of locating leaks in a pipeline, and it has been used widely in the energy distribution industry. However, it is difficult to obtain the pressure wave velocity accurately and to localize leakage by using NPW method because of the complexity of real pipeline components, especially in assembled pipeline. Thus, in this study, the influence of assembly rubber washer on pressure wave velocity is analyzed; in addition, considering the effect of the rubber washer, a numerical method for calculating the velocity of pressure wave propagation in liquid pipelines is proposed. Then, the propagation velocity of NPWs is measured experimentally to verify the feasibility of the improved method on a self-made pipeline leak detection test platform. The results show that the presence of rubber washers in an assembled pipeline decreases the propagation velocity of NPWs and that the correction model established in this study can adequately modify the propagation velocity of NPWs. The improved method containing the modified formula can improve the accuracy of leak localization for assembled pressurized liquid pipelines.