Traveling ability of pipeline inspection gauge (PIG) in elbow under different friction coefficients by 3D FEM

Abstract

Pipeline inspection gauge (PIG) applied for dewatering and cleaning operation frequently suffers from blockage risk, especially in elbow section. Definitive solution to the blockage problems does not currently exist in literature. In this research, the concept of traveling ability is introduced to describe the performance of blockage avoidance, and it is defined by three influencing factors: sealing performance, which is expressed by the leak area ratio of the PIG cups; driving performance, which is evaluated by the necessary driving pressure, and collision possibility, which is described by the minimum distance between the PIG head or tail and the pipeline inner wall during pigging. The 3D finite element model (FEM) is adopted in this work and is verified by a custom–built experimental setup. Then, the FE model of the PIG running in elbow is established, and the effect of friction coefficients on the influencing factors is discussed. The results indicate that the traveling ability of the PIG will be obviously weakened under the condition with the higher friction coefficients. When the friction coefficient increases from 0.1 to 0.5, the sealing performance decreases by 27.7%; the driving performance decreases by 80% and the collision possibility increases by 94%. The researches of this work are beneficial for improving the PIG designment and avoiding the blockage risk.