Accurate water hammer pressure modeling for automatic modification of stress distribution along multi-segment pipelines

摘要

In this study, automatic modification of stresses in rigid parts of a pipe line system is modelednusing the trial results of a second-order explicit Finite Volume (FV) Godunov type scheme fornone-dimensional transient flow in pipes. The developed model for numerical analysis of transientnpressure is based on Riemann solution of continuity equation coupled with the momentumnEquation (including convective term). The implementation of boundary conditions such asnreservoirs, valves, and pipe junctions in the Godunov approach is similar to that of the methodnof characteristics (MOC) approach. The computed pressure waves are compared with analyticalnsolution as well as laboratory measurements for single pipes. The model is applied on two classicnproblems (systems consisting of a reservoir, a pipe and a valve). The second-order Godunovnscheme is stable for Courant number less than or equal to unity, and therefore, can be appliednfor the problems with variable mesh spacing. In order to show the ability of the developed modelnto deal with such cases, the computed maximum pressure distribution along a pipeline with variablensegment coordinates are used for trial modification of pipe thickness and stress distribution.