PIPING FLUID TRANSIENTS MADE SIMPLE: Part Ⅱ APPLICATION OF THE SSFFC METHODS

摘要

Piping systems transporting fluid between plant components are subjected to a variety of anticipated and/or postulated flow changes that disturb their steady state operations. These changes cause the fluid flow to accelerate and/or decelerate. However, consideration of fluid elasticity transforms these disturbances into weak and/or strong propagating sound waves, depending upon the abruptness level of the fluid state change. This generates dynamic forces on the pipe segments of the piping system. A simple concept for understanding the piping fluid transient phenomenon from its physical perspective is presented. The piping system consists of several pipe segments, each segment having a constant cross-sectional flow area. The pipe segment is further divided into a consecutive series of zones. Each zone comprises two or three sub-zones of quasi steady state flow. The sub-zones are separated by interface fronts into which the jump in fluid pressure and velocity occurs across them. These fronts propagate and clash with each other to create the next temporal set of sub-zones quasi steady state flow. This method is denoted in this paper as steady state flow fronts clashing 'SSFFC'. Clashing between the incident, transmitted and/or reflected wave fronts within the zone are introduced. As a follow-up to the first part of this two-part publication, this paper demonstrates two sample applications of SSFFC method utilizing the proposed wave front bookkeeping technique.