Analytical study of frictional interaction of elastic cleaning pig with pipeline wall

Cleaning pigs made of highly elastic materials are used to remove contaminants from industrial gas pipelines. To ensure the movement of the pig in normal operation and narrow sections of the pipeline, it is necessary to generate the required gas pressure in the pig space. The study aims to establish the analytical conditions for the movement of a deformable pig in a cylindrical channel without stopping.A one-dimensional quasi-static model has been developed to analyse the frictional interaction of a moving deformable rod with a cylindrical pipe wall under conditions of uniform radial tightness. The normal contact is assumed to be dense, with no interfacial gas flow along the pig.Based on the solution of the formulated contact problem, the influence of frontal resistance, tension, friction, modulus of elasticity of the material and geometric dimensions of the rod on its stress state and on the value of pressure behind the pig required for the pig to pass through the pipeline without stopping is investigated. It is shown that an increase in the value of each factor leads to an increase in the driving gas pressure in the space behind the pig.In the future, developing the proposed approach for the analytical modelling of pig motion in a pipe with variable narrowing is advisable.Recommendations for the design of deformable pigs for efficient gas pipeline cleaning are given.In analytical form, the dependences of the driving pressure on the key geometric and mechanical parameters of the process were found.