Experimental and numerical investigation on hyperelastic sealing disc contact behavior in pipeline, a comparison between fluid-driven and pull-through approaches

Abstract

Pipelines are widely recognized as the safest and most efficient means of fluid transportation. Pipeline pigging, a secure and reliable technique, is employed for both cleaning and sealing pipelines to optimize efficiency. Since pigging operation requires differential pressure ($\Delta p$) to facilitate pig movement, this pressure must correspond to the pipeline’s operational conditions. Consequently, studying the required $\Delta p$ for sealing discs, which serve as primary sealing elements of pigs, is crucial. The primary focus of this study is to examine the difference between pulling the pig using a cable and propelling it with fluid. Furthermore, the main novelty of this research is to experimentally investigate a single sealing disc and conduct fluid-driven tests on it. To study more precisely, three sealing discs with various thicknesses and the same hardness have been launched into a 6-inch spool test, containing five pipes with different wall thicknesses, resulting in multiple oversize ratios (%Osz). In the experimental study, both fluid-driven and pull-through tests were conducted. The range of discrepancy between two methods varies from 15% to 26% for different oversize ratios which is considerable. Additionally, A 2-D axisymmetric nonlinear numerical simulation was conducted in a finite element software ABAQUS in order to study the behavior of sealing discs. Using a pressure-dependent friction coefficient with the proper hyperelastic model was key to achieving simulations that have good agreements with experimental results, with discrepancy of less than 10% in all extracted pressures.