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Pharmaceutical water systems: a thermal-fluid analysis of pipe dead-legs

Austen, Benjamin L. (2005) Pharmaceutical water systems: a thermal-fluid analysis of pipe dead-legs. Master of Engineering thesis, Dublin City University.

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The most commonly used technique for flow exchange, fluid isolation and removal in pharmaceutical water systems, is the installation of a branch tee with a conventional two-way outlet port valve. This however can create a stagnant or “dead-leg” zone, which is particularly hazardous as bacteria can accumulate and contaminate the entire water system. This project has involved the study of the thermal and fluid dynamics considerations within pipe dead-legs and their impact on high purity water systems. A detailed literature review of the technology surrounding pharmaceutical water systems was carried out to set the background for the analysis of pipe dead-legs. An experimental test rig was designed and constructed to represent a typical single loop water system incorporating a dead-leg test section. Results were obtained for a 6d, 4d and 2d branch tee configuration under dead-leg flow conditions. The effect of the main pipe loop velocity and temperature on the dead-leg end temperature was investigated. Determination of the temperature distribution along the axis of the dead-leg branch under steady state conditions was also investigated. It was shown that the maximum dead-leg end temperature increased for an increase in loop velocity for each configuration. Reducing the dead-leg length from a 6d to a 4d and 2d configuration respectively was shown to significantly increase the dead-leg end temperature. It was found that a zone of uniform temperature and a temperature decay region were present in each branch configuration respectively. It was shown that stagnant fluid was present at the end o f the dead-leg for the 6d and 4d configurations. The 2d dead-leg was found to be the most effective configuration to achieve full loop temperature penetration and mixing of the dead-leg fluid. The 6d rule was shown to be inadequate for both fluid mixing and loop temperature penetration.

Item Type:Thesis (Master of Engineering)
Date of Award:2005
Supervisor(s):Corcoran, Brian
Uncontrolled Keywords:flow; stagnant zones; dead legs; thermal dynmics
Subjects:Engineering > Computational fluid dynamics
DCU Faculties and Centres:DCU Faculties and Schools > Faculty of Engineering and Computing > School of Mechanical and Manufacturing Engineering
Use License:This item is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 3.0 License. View License
ID Code:17237
Deposited On:21 Aug 2012 14:40 by Fran Callaghan. Last Modified 21 Aug 2012 14:40

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