Effect of pipematerials on water hammer

摘要

Water hammer is a transient flow in pipes that were made by quickly change in speed in pipes. This phenomenon can cause genuine positive and negative pressures in pipes and frequently with hazards in pipelines. Generally, water hammer makes by closing valves quickly and has one of the most dangerous hydrodynamic phenomena in pressurized pipelines. In this paper, governing equations about water hammer is numerically fathomed by utilizing MATLAB programing language based on the method of characteristic (MOC), and then the pressure variations have been studied by changing some effective variables such as pipes elastic modulus and Poisson's ratio for four pipe materials. The numerical method is based on the method of characteristic lines. The present results showed that the normalized piezometric head which is calculated in 4 statuses (pipe's full length, pipe's 3/4 length, pipe's 1/2 length, and pipe's 1/4 length) is directly change with the change of elastic modulus and Poisson's ratio based on the pipe material,. The novelty of this study is to show how the materials with less elastic modulus are less likely to occur the water hammer than the high elastic modulus for the same operation condition.