Performance Analysis of Cup-Type Pipeline Pigs Passing through Slopes Based on CEL

During pipeline inspection, pipeline pigs often experience extrusion-induced deformation when passing through slopes, leading to cup seal failure and an increased risk of blockage. This can negatively impact subsequent inspection and cleaning efficiency. To investigate the passing performance of pipeline pigs on slopes, this study established a coupled Eulerian–Lagrangian (CEL) model for pipeline pigs and pipe, comparing non-fluid–structure interaction (non-FSI) models with fluid–structure interaction (FSI) models, and finding that the latter better represents the actual operating conditions of pigs inside pipelines. Based on this, a three-dimensional FSI simulation model using the Eulerian–Lagrangian method is established, focusing on a cup-type pig passing through a 135° sloped pipeline. The study examines the effects of cup structural parameters—such as the interference amount, cup thickness, and clamping ratio—on the pig’s passing performance. Through comparative analysis of simulation results, the optimal parameter combination is determined: an interference amount of 3.41%, a cup thickness of 18 mm, and a clamping ratio of 61.7%. This research provides a theoretical basis for improving the passing performance of pipeline pigs through slopes and ensuring the safety and efficiency of pig operations.