The effect of orifices and blockages on unsteady pipe flows

Abstract

The unique unsteady behavior of flow system components causes a major obstacle to the development of a precise transient analysis model for a pipeline. This research investigates the dynamic characteristics of orifices and blockages. The dynamic flow behavior through a pipe restriction can be represented by three different energy loss factors, which include the irreversible energy loss by turbulent jet flow, the kinetic pressure difference represented by the instantaneous flow acceleration and deceleration, and pressure wave dispersion by eddy inertia of the jet flow. The study proposes instantaneous inertia and frequency-dependent models to describe the kinetic pressure difference. The traditional steady-state characteristics of an orifice are used to calculate the net pressure loss, and the wave dispersion by turbulent jet flow is considered by the wavespeed adjustment method. An experimental investigation has been carried out for the single pipeline system with various orifices and blockages. © 2007 ASCE.