Dynamic Analysis of Pig through Two and Three Dimensional Gas Pipeline

This paper deals with the dynamic analysis and simulation of Pipeline Inspection Gage (PIG) through the two and three dimensional gas pipelines. Continuity, momentum and the state equations are employed to achieve the gas flow parameters like density, velocity and pressure along the pipeline since the dynamic behavior of the pig depends on the flow field characteristics. Also, a differential equation which governs the dynamic behavior of the pig is derived. The pig is assumed to be a small rigid body with a bypass hole in its body. The variation of the diameter of the bypass port, which is controlled by a valve, is considered in this research. The path of the pig or geometry of the pipeline is assumed to be 2D and 3D curve. 2D and 3D simulations of the pig motion are performed individually using Rung- Kutta method and a case has been solved and discussed for each of them. The simulation results show that the derived equations are valid and effective for online estimating of the position, velocity and forces acting on the pig in gas pipelines at any time of the motion.