Application of higher-order TVD resolution for investigation of transients problems in natural gas pipelines

A higher-order numerical procedure is applied to simulate typical transient phenomena in natural gas transportation. Reliable modeling and prediction of transients features in transmission pipelines are desirable for optimal control of gas deliverability, design and implementation of active controls, and modeling of operational behavior of network peripheral equipment (e.g., chokes, valves, compressors, etc.). As an alternative to the Method of Characteristics (MOC) that is widely used presently, a higher-order Total Variation Diminishing (TVD) method is used to model some transient problems. This class of methods has the capability to capture fine-scale phenomena and provides a better resolution of frontal discontinuities. In this study, the TVD method is utilized in conjunction with upwind methods. Also, in order to ensure a stable time-stepping scheme over a wide range of Courant-Friedrich-Lewy (CFL) number, a special Runge-Kutta method is employed as the base solution algorithm to integrate the highly non-linear, hyperbolic equations which govern the transportation of natural gas in pipelines. The overall procedure is stable, robust and accurate when applied to solve practical problems with simulated pressure waves.