Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X51520191222Interdependence of Hydraulic Parameters in Transient Induced Contaminant Intrusion in a PipelineInterdependence of Hydraulic Parameters in Transient Induced Contaminant Intrusion in a Pipeline10171032303610.22060/ceej.2018.14486.5670FAMiladPayestehMsc graduated in Civil Engineering, Jundi-Shapur University of Technology, Dezful, IranAlirezaKeramatFaculty of Civil Engineering, Jondi Shapur University of Technology, Dezful, Iran0000-0002-6280-4931Journal Article20180523Contaminant intrusion during transients in pipelines is a remarkable mechanism which usually leads to declining the quality of the contained water. When rarefaction waves of water hammer reach a leakage, the negative pressure can suddenly suck pollution from surrounding area of leakage to the main pipe flow, thus deteriorating water quality. In this research, numerical and mathematical modeling of a reservoir-pipe-valve system with a leakage has been used to study the effect of hydraulic situations on the volume of contamination intruded into the pipeline during a waterhammer. Eulerian method of characteristics was employed to model the transient flow. The total Volume of Contaminant Parcel (VCPt) penetrating through the leakage is evaluated by Lagrangian solution of the advection equation and then it is established the criteria to compare various transient scenarios and the interconnection between key parameters. In order to elucidate this phenomenon in real pipe systems, the amount of contaminant intrusion is estimated for 72 different cases. They include two lengths of pipeline (say short and long), three different leakage locations, three different fluid velocities, two leak diameters and two pipeline materials (elastic and viscoelastic). The results indicate that the amount of intrusion in viscoelastic pipes is clearly less than that in elastic pipes especially in long pipelines: the ratio of intrusion in viscoelastic to elastic pipes on average is 0.027 and 0.496 in 2300m and 540m pipe, respectively. The critical zone of high intrusion risk is placed close to the downstream valve for small leak sizes, nevertheless, it is hard to estimate this zone in case of big leaks due to significant valve-leak-reservoir induced reflection waves.Contaminant intrusion during transients in pipelines is a remarkable mechanism which usually leads to declining the quality of the contained water. When rarefaction waves of water hammer reach a leakage, the negative pressure can suddenly suck pollution from surrounding area of leakage to the main pipe flow, thus deteriorating water quality. In this research, numerical and mathematical modeling of a reservoir-pipe-valve system with a leakage has been used to study the effect of hydraulic situations on the volume of contamination intruded into the pipeline during a waterhammer. Eulerian method of characteristics was employed to model the transient flow. The total Volume of Contaminant Parcel (VCPt) penetrating through the leakage is evaluated by Lagrangian solution of the advection equation and then it is established the criteria to compare various transient scenarios and the interconnection between key parameters. In order to elucidate this phenomenon in real pipe systems, the amount of contaminant intrusion is estimated for 72 different cases. They include two lengths of pipeline (say short and long), three different leakage locations, three different fluid velocities, two leak diameters and two pipeline materials (elastic and viscoelastic). The results indicate that the amount of intrusion in viscoelastic pipes is clearly less than that in elastic pipes especially in long pipelines: the ratio of intrusion in viscoelastic to elastic pipes on average is 0.027 and 0.496 in 2300m and 540m pipe, respectively. The critical zone of high intrusion risk is placed close to the downstream valve for small leak sizes, nevertheless, it is hard to estimate this zone in case of big leaks due to significant valve-leak-reservoir induced reflection waves.https://ceej.aut.ac.ir/article_3036_3a946b8af342e6fe9b18e53dce7adedc.pdf