The Model and the Methods for Numerical Simulation of Wave Action of Real Working Fluids in Pipelines

The conservation laws and the equations of state for quasi-1D motion of compressible fluid in pipeline are formulated in general form, along with the conservative monotone methods suitable for real (multi-component, multiphase) working fluids. The objective is to present a concise approach to construct a general purpose model of pipeline flow for the applied software package, and to present some validation results. The known achievements on higher order monotone schemes for the hyperbolic conservation laws are applied to solve generalized problems of flow in pipes. Specifically, characteristic-based reconstruction and approximate solution to Riemann problem in Godunov-type schemes are used to incorporate real working fluids' equations of state into explicit numerical schemes. Preliminary validation of the model and the computer code is done for equation of state of perfect gas as a special case. Shown are the solutions to problems for 2 validation cases: (a) Riemann problem (compared with exact solution) and (b) problem of wave action (compared with the experimental data obtained on a single-cycle installation). The results encourage further generalization and testing the model applied to real and multiphase fluids and for compliant pipes.