Transient Cavitating Pipe Flow

Abstract

When a liquid column in a pipeline is pulled apart by the upstream velocity being less than the downstream velocity for a sufficient period of time, cavitating flow occurs over portions of the pipeline. The cavitating flow, with vapor pressure at its surface, is acted on by friction and by gravity (for sloping pipes). Analytical equations are developed which yield vaporous velocity and vapor fraction as functions of time and distance throughout the cavitating regions. These regions may be reduced only through consolidation caused by liquid impingement. Equations for the pressure rise across the shock face and for speed of consolidation are developed. A program which includes these concepts permits transients in piping systems to be calculated for several boundary conditions. Comparisons with experiment and with other methods are presented.