Analysis of the Trafficability of Spherical InternalDetectors in Pipelines

This study aims to enhance the motion stability of a spherical internal detector within a flow field, thereby preventing jamming or deviations during the inspection process. Firstly, a fluid-structure interaction model of a spherical detector in a pipeline was built, and flow field calculations were performed for a straight pipe and a 60° elbow with a 600 mm diameter, examining various ball-to-pipe diameter ratios. The analysis, including the flow field and pressure distribution characteristics of the spherical internal detector within the pipe configurations, was supplemented by experimental verification. The findings reveal that the thrust generated by the spherical internal detector correlates positively with the ball-to-pipe diameter ratio. However, an excessively high ratio 0.8 led to a rapid decrease in fluid velocity in the wake region and an increase in the radial region. Significantly, when the spherical internal detector navigates through a 60° pipe elbow, its angular velocity triples compared to that in a straight pipe section, potentially reducing the detector’s service life. For 600 mm diameter pipes, it is recommended that the optimal condition is achieved with a ball-to-pipe diameter ratio of 0.6 and an initial fluid flow velocity of 1.5 m/s to exte