Single- phase flow instabilities: Effect of pressure waves in a pump–pipe–plenum–choke system

Abstract

To determine whether or not an equilibrium solution of a system of differential equations is stable, usually two methodologies are used: local linearization analysis and transient simulation. The first approach is based on local linearization around the equilibrium solution in order to develop simple analytical criteria. Although represented by easy inequalities that depend on steady-state parameters, these criteria provide only limited information about the problem and due to simplifying assumptions, the criteria may misrepresent the physical reality. The second approach, transient simulation, seems to be the method that leads to results that are closer to reality. This work presents a review regarding instability of dynamic systems and its application to a pump-pipe-plenum-choke liquid-single-phase flow system. The validity of such criteria is discussed and comparisons with incompressible and compressible transient simulations are made. Effects of pump performance curve, use of check-valve, choke size and pressure waves in the system (compressible model) are discussed along the work.