Numerical modeling transient flow in plastic pipes

N Achak,K Gueraoui,B Bahrar,S Aniss

doi:10.1051/matecconf/201928607001

Abstract

We present a numerical code for calculating transient flow in plastic pipes, especially in the polyethylene pipe, to analysis effect of material viscoelasticity on water hammer phenomena. The set partial differential equations to be solved is obtained using conservation laws and behavior for the fluid and the pipe wall, associated with constitutive equations of the two media, and relationships compatibility of interfaces on velocities and stresses. A global digital processing is achieved using the method of characteristics. The results obtained are in good agreement with those found in the literature.

Highlights

Water hammer, or hydraulic transient, refers to pressure fluctuations caused by a sudden increase or decrease in flow velocity
In the field of plastic materials, the pioneering studies appear to be those of Tison in 1958 [4], who had noticed the influence of viscoelasticity on the transient flow behavior associated with the valve opening
The interest of this study is the use of increasingly growing plastic tubes (PVC, polyethylene,...) in different industries and service life compared to traditional piping materials

Summary

Introduction

Hydraulic transient, refers to pressure fluctuations caused by a sudden increase or decrease in flow velocity In this way, many theoretical and experimental studies have, usually, conducted assuming linear elastic behaviour of the pipe wall without mass [1, 2, 3], that is means, time scales of inertia of pipe wall is negligible. The interest of this study is the use of increasingly growing plastic tubes (PVC, polyethylene,...) in different industries and service life compared to traditional piping materials. This leads us to examine the influence of the viscoelastic behavior of these materials on hydraulic transient flows. A comparison and validation of our code is done with the measurement results conducted by Güney [8], at INSA Lyon

Assumptions and basic equations

Initial and boundary conditions

Numerical solution

Application and results

Conclusion